MAG TECH 1 Magnesium

GLOBAL WATCH MISSION REPORT

MAG TECH 1: Magnesiumalloys and processingtechnologies for lightweighttransport applications – a mission to Europe

SEPTEMBER / OCTOBER 2004

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MAG TECH 1: Magnesiumalloys and processing

technologies forlightweight transport

applications– a mission to Europe

REPORT OF A DTI GLOBAL WATCH MISSION SEPTEMBER/OCTOBER 2004

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MAG TECH 1: MAGNESIUM ALLOYS AND PROCESSING TECHNOLOGIES FOR LIGHTWEIGHT TRANSPORT APPLICATIONS – A MISSION TO EUROPE

CONTENTS

Acknowledgments 3

Foreword 4

Executive summary 5

1 Introduction 61.1 Background to mission 6

2 Objectives of mission 82.1 Specific objectives 82.2 Benefit to the UK 82.3 The mission 82.4 The mission team 9

3 Novel casting technologies 103.1 LKR – new rheocasting (NRC) 12

process3.2 RWTH Aachen – rheo-container 13

process (RCP)3.3 RWTH Aachen – rheocasting 14

using cooling channel3.4 RWTH Aachen – thixomoulding 14

of magnesium3.5 RWTH Aachen – thixocasting of 14

magnesium3.6 RWTH Aachen – investment 16

casting of magnesium3.7 Gravity casting 163.8 Sand casting 163.9 BCAST rheo-diecasting (RDC) 17

process3.10 Casting alloy development 183.11 High-pressure die-casting alloys 20

and key development drivers3.12 Gravity casting alloy 21

development3.13 Other casting technology 21

research3.14 Summary 23

4 Developments in processing 25and manufacture of componentsfrom wrought magnesium

4.1 Extruded magnesium profiles 254.1.1 ‘Take-Off’ (aerospace) project 274.1.2 VW 1-litre car 284.1.3 Formability 284.2 Sheet magnesium 284.2.1 Future development 31

requirements4.3 Forged magnesium 32

5 Joining technologies and 33integration

5.1 Laser welding 355.2 Friction stir welding (FSW) 365.3 Mechanical joining 365.4 Resistance spot welding (RSW) 375.5 Co-extrusion 375.6 Mechanical fasteners 38

6 Magnesium surface treatments 406.1 Mission objectives 41

(surface treatments)6.2 NANOMAG 416.2.1 PAPVD 436.2.2 PECVD 436.2.3 Sol-gel 436.2.4 Keronite (PEO) 436.3 Highlights 446.3.1 Industrial perspective 446.3.2 Academic and RTO perspective 456.3.3 Perceived technical/economic 47

barriers6.3.4 Current and future research 47

priorities6.4 Conclusions 48

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7 Potential future applications 49and techno-economic issues

7.1 Introduction 497.2 Magnesium supply and demand 49

in western Europe7.2.1 Magnesium supply 497.2.2 Magnesium demand in western 50

Europe7.2.3 Magnesium demand in the UK 517.3 Wrought alloys 517.4 Automotive applications 517.4.1 Powertrain 517.4.2 Structural castings 527.4.3 Other castings 527.4.4 Wrought applications 527.4.5 Beyond automotive applications 527.5 Conclusions 54

8 R&D funding and 55infrastructure

8.1 EU research projects 558.2 Additional projects 588.3 Summary and 59

recommendations

9 Industry perceptions and 61training and education

10 General conclusions 6210.1 Research 6210.2 Industry misconceptions 62

11 Key findings 63

12 Recommendations and 64follow-up actions

AppendicesA Host organisation profiles 65B Mission team details 69C List of exhibits 75D Glossary 77

ACKNOWLEDGMENTS

The mission team would like to extend theirdeepest thanks to the host organisations fortheir hospitality, openness and support,without which the mission and this reportwould not have been possible.

We would also like to acknowledge thesupport of the DTI Global Watch Service inboth the organisation and funding of themission and its dissemination through theseminar event. The team would also like tothank numerous individuals at the DTI, theiragents and also the various consulates forwork behind the scenes.

A large thanks is also owed to Frank Rott,Martin Kemp, Craig Wallbank and CharlotteLeiper of the DTI Global Watch Service fortheir support to the success of this mission.

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FOREWORD

The new millennium has seen major growth in the use of magnesium alloys as structuralmaterials in automotive and other applications.Spearheaded by the developments ofcorrosion-resistant alloys and improvements in high-pressure die-casting (HPDC)technologies, automotive applications inEurope have shown double-digit growth forthe last 10 years.

The forefront for this growth has been theGerman automotive industry, led by the VW Passat gearbox first produced in 1996. The developments are continuing with therevolutionary 6-cylinder magnesium engineblock from BMW launched in 2004 and the new DaimlerChrysler 7-speed gearbox housing.

In addition to the automotive sector, the new developments in magnesiumtechnology are having a major impact onareas as diverse as sports goods, aerospace and even biomedical prostheses.

The MAG TECH 1 mission has highlightedthe extensive research and development(R&D) being carried out by Europeanuniversities and research bodies, with majorsupport funding from national governmentsand the European Union. The mission hasclearly shown that although the UnitedKingdom has some world-class players inmagnesium technology, it is liable to fallbehind Europe if steps are not taken tosupport R&D within both the UK’s academicsystem and industrial base.

It is clear from the report that magnesiumalloys are no longer viewed as niche orexotic materials in Europe. In order for UK manufacturing to compete onlightweighting, recyclability and functionality,designers need to be aware of the excitingopportunities magnesium alloys present as areal economic alternative to steel, aluminiumand plastic for today’s lightweight products.

Chris DaggerDivisional ManagingDirectorMagnesium Elektron Ltd

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EXECUTIVE SUMMARY

Magnesium is now becoming the material of choice for many lightweight transportcomponent applications, demonstrated bycontinued, steady market growth. In thealloyed form, magnesium is the lighteststructural metal, thereby providingconsiderable opportunity to improve fueleconomy and reduce harmful emissionsproduced in powering transport whensubstituted for a heavier aluminium or steel design.

The purpose of this DTI Global WatchMission, coordinated by Faraday Advance,was to evaluate the European state-of-the-artin terms of magnesium alloys andtechnologies for improved componentmanufacture and in-service performance. It is understood that considerable researchand development (R&D) activities involvingmagnesium have taken – and continue totake – place in Europe, outside the UK. Muchof this R&D has been heavily funded throughthe European Commission (EC) and throughnational programmes.

This mission, which took place during 27September – 1 October 2004, focused onidentifying essential information, including:

• future trends and technology drivers • technology barriers • enabling technologies or developments

required to move towards greater levels ofmagnesium deployment in themanufacture of automotive products

The report provides an overview of themission, which encompassed technicaldiscussions, reviews and observations frommeetings held with key Europeanorganisations involved in the research,development and application of magnesium.The aim of this mission was to capture abroad insight into the general trends andissues associated with magnesiumtechnology and to identify key opportunitiesfor the UK to improve its competitiveness inthis field in the form of key findings andrecommendations. During the visit, a wealthof information and material was gatheredfrom the organisations and experts visited,providing a valuable source for universityresearchers, small or medium enterprises(SMEs), industrial producers, users andtechnology providers. This material is capturedin this report.

1 INTRODUCTION

In the manufacture of transport, weightreduction through the use of lightweightmaterials remains a very successful andsimple means of improving fuel economyand reducing harmful emissions. High-puritymagnesium alloys are now sophisticatedmaterials that provide significantopportunities for weight reduction andtherefore real scope to achieve theseenvironmental goals.

Increases in magnesium alloys forautomotive applications have driven thesubstantial increase in magnesium worlddemand; in particular, magnesium alloys formaking die-cast components. According toAustralian Magnesium Corp Ltd (AMC), die-cast magnesium automotive componentsaccount for ~150,000 t/y of magnesiumalloys1 and dominate the application ofmagnesium die-castings. This substantial andsustained increase in magnesiumconsumption has led to significant changesin the magnesium manufacturing industryand has encouraged suppliers to developtheir processes and alloys and identifypotential future applications of magnesiumfor both cast and wrought products.

According to the International MagnesiumAssociation (IMA), world consumption ofmagnesium has seen a 30% increase overthe last eight years, and has been forecastto continue to grow at a rate of 3% annually.This has encouraged primary metalproducers to invest in new capitalequipment and plant to meet the sustainedgrowth in demand. In 1999, worldmagnesium consumption was some320,000 t, with expectations that it may riseto some 500,000 t by 2005.

The key interest in magnesium forstructural and non-structural componentapplications is in its potential for weightreduction. In the alloyed form, magnesiumis the lightest of all the structural metalsand can provide a host of additionalcomponent benefits depending uponproduct form.

It is also important to note the impact thatother industry sectors may have indeveloping and increasing the demand formagnesium components, which willcontribute to lowering magnesium alloyprices and improving product performance.The potential of magnesium to the UKeconomy and automotive manufacturingalone is quite staggering. The UK producessome 1.8 million passenger vehicles perannum, with a considerable number ofthese – typically ~50% – becoming exportproducts. The introduction of moremagnesium components that are producedin the UK would therefore appear to providea significant opportunity for the UK to meetfuture emissions targets, whilst reservingnatural resources and enhancing thecompetitiveness of the UK.

1.1 Background to mission

Outside the UK, there has been significantresearch activity in the field of magnesiumalloys and technologies for automotiveapplications. The research is beingconducted to address the barriers togreater levels of magnesium deployment.The principal countries involved in thetechnical visits included:

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1 Magnesium Automotive Potential, Australian Magnesium Corp Ltd – Fact Sheet 11, December 2000, ABN 51 010 441 666:www.austmg.com/documents/11_Auto%20Potentail.pdf

• Germany – centre for large magnesiumR&D network of institutes, magnesium component producers andvehicle manufacturers

• Austria – through the Austrian ResearchCentres (ARC)

• Italy – home to the largest Europeanmagnesium die-casting facility (MeridianMagnesium Products of Italy srl – MPI)and a major user of magnesium products(Fiat)

These countries were identified as having asignificant impetus on magnesiumdevelopments through internal companyR&D and involvement in government-fundedor EU research programmes. From thesecountries, key organisations were identifiedto hold bilateral technical discussions relatingto the developments and trends inmagnesium alloy and technology and itsusage in product applications.

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2 OBJECTIVES OF MISSION

High-purity magnesium alloys are nowsophisticated materials that provideopportunities for significant weight reductionof components and therefore real scope todeliver against the environmental drivers,particularly emissions.

The high-level aim of this mission was toevaluate the state-of-the-art in magnesiumalloys and technologies for improvedcomponent manufacture and in-serviceperformance for the automotive industry.The mission was focused on identifying keyinformation on the future trends and drivers,technology barriers and the enablingtechnologies or developments required tomove towards greater levels of magnesiumdeployment in the manufacture ofautomotive products.

It is strongly believed that the mission will –in the medium term – provide a suitablevehicle to promote the initiation ofappropriate R&D projects or programmes inthe UK and – in the longer term – result inthe increased deployment of magnesiumcomponents displaying higher levels of UKtechnology in the automotive supply chainwith good opportunities to transfer thistechnology into other sectors.

2.1 Specific objectives

Specific objectives of the mission were to:

• Discuss issues relating to the design,alloy selection, manufacturing technique,coating and finishing of magnesiumcomponents

• Identify and discuss technology barriers andkey enabling technologies necessary tomove towards greater levels of exploitation,in terms of both cast and wroughtmagnesium component applications

• Engage in specific technical evaluationsand discussions regarding key appliedresearch and envisaged future trends

• Understand national market perceptionsand trends for magnesium usage

• Discuss national, EC-funded andcommercial research programmes, andidentify any synergies with the UK andopportunities for collaboration

• Explore bilateral secondmentopportunities between UK organisationsand hosts

2.2 Benefit to the UK

The dissemination of this information to UKcompanies, research organisations andfunding agencies will enable them to identifytechnology gaps, and focus developmentprogrammes, with the potential to transferthe knowledge and information to differentindustry sectors.

2.3 The mission

The mission took place during 27 September – 1 October 2004, visitingthe many organisations identified as centresof excellence in the R&D or manufacture ofmagnesium-related products orcomponents. The mission team had theopportunity to discuss and present R&Dwork in the field of magnesium alloys andtechnology during visits to the followinghost organisations:

• ARC LKR, Ranshofen (Austria)• BMW, Munich (Germany)• RWTH, Aachen (Germany) • GKSS, Geesthacht (Germany)• IFAM, Bremen (Germany)• MPI, Verres (Italy)

During the visit at RWTH Aachen, the meetingwas jointly attended by Ford Research Centre;and at GKSS, by Salzgitter Magnesium-Technologie GmbH (SZMT). IFAM staged anetworking event attended by Oskar FrechGmbH + Co KG (producer of die-castingequipment), HDO (manufacturer ofmagnesium die-castings) and HannoverUniversity, providing a unique opportunity topresent and discuss developments in Europeand the UK. This format provided an excellentmeans by which the mission team could meetseveral organisations that would otherwisehave been logistically impossible. Details ofthe mission hosts are available in Appendix A.At the visit to MPI, CRF also attended.

Whilst the mission team met with the majororganisations mentioned above, theserepresent only a small proportion of thetotal magnesium research and productionefforts in Europe, outside the UK. However,the selection of organisations provided avery strong illustration of the breadth anddepth of the research activity anddevelopment trends.

2.4 The mission team

A select number of individuals were chosenas mission delegates, representing the UK(see Exhibit 2.1). A key factor in theselection was involvement in the supplychain or potential supply chain, which wouldbe a critical factor in the success of follow-up activities. Individuals were selected froma mixture of backgrounds to provide a well-balanced team in order to achieve thegreatest contribution. Details of the missionteam are available in Appendix B.

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Exhibit 2.1 Mission team at BMW (FIZ), Munich

3 NOVEL CASTING TECHNOLOGIES

Currently, the majority of components thatare made from magnesium alloys areproduced using conventional hot-chamberand cold-chamber forms of high-pressuredie-casting (HPDC) processes, creating parts that may have very complexgeometries, exhibiting multifunctionaldesigns. Structural HPDC parts aremanufactured using the cold-chamberprocess (see Exhibit 3.1), as this is bettersuited to achieving larger components whilststill retaining the necessary mechanicalproperties for these applications.

A recent, major achievement in Europe inHPDC is the series production of themagnesium composite crankcasemanufactured by BMW in Germany. Thecrankcase is manufactured from a high-pressure die-casting of AJ62 magnesiumalloy, and incorporates an aluminium alloy

(AlSi17) low-pressure die-casting (LDPC) forthe cylinder linings. Through this technology,BMW is able to achieve lightest 6-cylinderengine in its class, weighing a mere 161 kg.

Die-casting is an exceptionally efficientmeans of producing magnesiumcomponents but it does have somelimitations due to the aggressive nature ofthe process, which induces high levels ofturbulence at high velocity during metalinjection, resulting from the high pressure.This high level of turbulence combined withentrapped air results in porosity, which isdetrimental to the key mechanical propertiesof tensile strength and elongation. Theentrapped porosity will also impact uponother key performance attributes necessaryfor automotive applications, includingdurability and pressure tightness.

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Die Hydraulic press

Shot sleeve

Ram

Die cavity

Molten shot

Exhibit 3.1 HPDC cold-chamber process

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The current applications of magnesium inthe automotive industry are predominantlyproduced using the HPDC process.However, HPDC components are currentlylimited to functional and secondary structuralapplications rather than primary structuralapplications. Further increase in magnesiumapplications requires the development ofnovel casting technologies.

Objectives of the mission included:

• Assess the current status of thedevelopment of magnesium castingtechnologies

• Assess the current UK status in theEuropean context

• Make recommendation for futuredevelopment in the UK

New casting technologies for use withmagnesium alloys have been constantlypursued in R&D. The main driver and focusof process and alloy development has beento achieve improved mechanicalperformance, in terms of tensile strength,elongation and pressure tightness which canbe achieved with lower or zero levels ofporosity. In doing so, the improvedmechanical performance provides theopportunity for components to feature innew applications.

The current applications of magnesium in theautomotive industry constitute almost 100%cast components without any significantcontribution from the wrought products. The majority of the cast components areachieved by the HPDC process, which can bepressure die-cast using either the hot-chamber or cold-chamber process, asillustrated schematically in Exhibit 3.1.

The hot-chamber process is suitable forcomparatively small and thin-walledcomponents, and higher volume outputs,whilst the cold-chamber process is for largeand thick-walled components.

The HPDC process is characterised by highvolume, high efficiency, and low productioncost. However, the quality of componentsmanufactured by the HPDC process islimited by the presence of a substantialamount of porosity, which not only excludesthe application of HPDC components inhigh-safety and airtight systems, but alsodenies the opportunity for further propertyenhancement by heat treatment. It is clearthat further increase in magnesiumapplication in the transport industry willrequire a major advance in processingtechnologies. The new processes need to becapable of producing components of highintegrity and improved performance whilebeing comparable with the HPDC process interms of production cost and efficiency.

Porosity due to turbulent mould filling couldbe reduced or even eliminated if theviscosity of the melt could be increased toreduce the Reynolds number sufficiently sothat trapped air is minimised. This is theconcept of semi-solid metal (SSM)processing. Depending on the way thesemi-solid slurry is achieved, SSMprocessing techniques can be divided intotwo categories:

• Thixo• Rheo

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In the thixocasting process, nondendriticalloys preprocessed usually byelectromagnetic stirring are reheated to thesemi-solid region prior to casting by theHPDC process. As a processing technique,thixocasting does improve componentintegrity and performance, but proves to becost intensive, lacking in flexibility, anddifficult to scale-up. After 30 years ofextensive R&D, thixocasting is currentlyexperiencing a decline in acceptance as aviable production technology.

Another SSM process under R&D in Europeis thixomoulding (eg at GKSS and RWTHAachen), which was originally developed byDow Chemicals and is currently marketedby Thixomat Inc in the USA. In thethixomoulding process, magnesium chipsare fed into a single-screw injection-moulding machine and converted into semi-solid slurry which is then injection-mouldedinto components, somewhat similar toinjection moulding of polymeric materials.The thixomoulding process is currentlyexperiencing some degree of success,particularly in Asia, for casing applications inthe electronics industry. However, thisprocess is much less popular in Europe, andonly a few machines are available inresearch laboratories.

The general understanding is thatrheocasting has many advantages overthixocasting due to lower production cost,better component quality and ease ofscaling up. In the rheocasting process, semi-solid slurry is produced by controlled coolingof a liquid alloy into its semi-solid region,prior to shaping into components.

3.1 LKR – new rheocasting

(NRC) process

The currently most popular rheocastingprocess in Europe is the so-called newrheocasting (NRC) process, as schematicallyillustrated in Exhibit 3.2. In the NRC process,a given dose of liquid alloy with lowsuperheat is poured into a steel cup for acontrolled cooling into the semi-solid regionand followed by a short period of inductionheating before component production by asqueeze or die-casting process.

The NRC process is currently underintensive R&D in both LKR in Austria andCentro Ricerche Fiat (CRF) in Italy and issupported by the EU FP6 researchprogramme RHEOLIGHT. Compared withthixocasting, the NRC process is a lowercost process due to the use of liquid alloy asthe feedstock, enabling a greater degree ofprocess control.

Solidification nuclei

Pouring of melt

Controlled cooling, solidification and growth of nuclei

Induction heating

Air cooling

Die casting or squeeze casting

Exhibit 3.2 New rheocasting (NRC) process

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Exhibit 3.3 Mission team at the Foundry Institute, RWTH Aachen

Although the NRC process remains atlaboratory scale, trials have shown strongindications that economically it wouldachieve component production with nomaterial on-cost, similar cycle times andtherefore similar part costs to thoseproduced by HPDC. However, it is envisagedthat the NRC process will involve slightlyhigher capital equipment investment.

LKR was of the opinion that the NRCprocess it has been investigating displaysexcellent opportunity for new markets dueto its high strength. The NRC process willbe evaluated in the EU’s RHEOLIGHTresearch programme.

Other rheocasting processes under R&Dinclude the rheo-container process (RCP)developed by the Foundry Institute atAachen University of Technology (RWTHAachen), and the cooling slope process –originally developed in Japan – also underinvestigation by the Foundry Institute. Both these processes still remain at thelaboratory stage.

The mission team had a tour of RWTHAachen’s impressive foundry facilities (seeExhibit 3.3), including a quick review of theequipment and practical research, of which asignificant level was for company sponsors.

3.2 RWTH Aachen – rheo-container

process (RCP)

Due to the issues and limitations ofthixomoulding and thixocasting, and in orderto minimise the complexity of therheocasting process, RWTH Aachen hasbeen investigating a new rheocastingconcept – the so-called rheo-containerprocess (RCP) – that involves a melt beingpoured into a container under protective gascover. The melt is poured at a temperatureas close to the liquidus as possible to avoidrapid rates of cooling. After a satisfactorytemperature is reached, the semi-solid slurryis inserted into a conventional HPDC shotsleeve and finally formed (see Exhibit 3.4).

RWTH Aachen claimed that the RCP will bemore reproducible. However, there appear tobe issues in transferring the slurry into the

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Controlled cooling, solidification

and growth of nuclei

Protective cover gas

TMELT TLIQUIDUS

Ceramic containerSemi-solid slurry

Solidification nuclei

Pouring of melt

~~

Die casting or squeeze casting

Exhibit 3.4 Rheo-container process (RCP)

shot sleeve. The transfer is likely to causecooling and be detrimental to the slurry interms of its homogeneity, and uniformdistribution of fine solidification nuclei.Cooling on transfer will result in a coarsegrain size and a greater level of non-uniformity. This will translate into potentialporosity, and inferior mechanical properties.The solution currently does not appear tohave been developed.

3.3 RWTH Aachen – rheocasting

using cooling channel

RWTH Aachen has carried out some fairlyrudimentary trials to generate the requiredconditions for rheocasting, which has beenachieved by pouring a melt into a ceramiccooling channel and subsequently into acontainer to develop a semi-solid slurry (see Exhibit 3.5).

Whilst the apparatus used for these researchtrials was relatively crude, it demonstratedthat rheocasting conditions could be achieved,but using such a method for volumeproduction would create difficulties in

delivering reproducible results. The sphericalor globular grain morphology achieved usingthe cooling channel is illustrated in Exhibit 3.6.

3.4 RWTH Aachen – thixomoulding

of magnesium

Whilst thixomoulding of magnesiumcomponents is an expensive means ofproducing large components, trials at RWTHAachen into alloy mixing have establishedthat it was possible to improve upon creepproperties through selective mixtures, andtherefore tailor the degree of alloy mixing toachieve the required properties.

3.5 RWTH Aachen – thixocasting

of magnesium

The outline process for thixocasting isillustrated schematically in Exhibit 3.7.

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Ram

CoolingSmelting Billet cutting Billet reheating

Exhibit 3.7 Thixocasting process

Exhibit 3.5 Rheocasting using cooling channel

Exhibit 3.6 Cooling channel rheocasting grainmorphology

200 µm

The Foundry Institute has been active intrials with the thixocasting process;however, the process is currentlyuneconomic due to the control required forthe heating and homogenisation of thethixocasting feedstock material. The FoundryInstitute’s thixocasting machine is shown inExhibit 3.8.

Aside of SSM processing technologies, othercasting technologies for magnesium alloyshave been heavily researched in Europe.These include low-pressure die-casting(LPDC) for magnesium-alloy wheels, squeezecasting for transmission mounting, and sandcasting for engine support as featured in theFP6 MG-CHASSIS programme coordinated byFraunhofer IFAM in Germany. Other castingprocesses under development includemagnesium upcasting to replace the currentcontinuous direct-chill (DC) casting process(Hannover University), investment casting(Aachen) and magnesium foaming process(Hannover, Aachen and IFAM). An interestingapplication of magnesium castings and foamsis for medical applications where it maypotentially find application for absorbableimplants for the repair of bone fractures(Hannover University). Aachen wasresearching cellular type structural casting,displaying similarities to bone structure,produced by investment casting. These could find application in bio-medics,but also potentially in structural applicationswhere more-efficient natural structuresreplace man-made designs.

3.6 RWTH Aachen – investment

casting of magnesium

Due to reactions with conventional silicondioxide (SiO2) shell systems, RWTH Aachenhad been researching organic bindersystems. So far, the initial trials had beensuccessful, with the binder demonstratinggood temperature resistance and gaspermeability combined with resistance toreactivity with the melt. The investmentcasting route for magnesium alloys appearsto show promise for high- and low-volumecomponents in the absence of high capital-investment costs but where demanding,complex geometries were desired.Limitations of course remain, including theabsence of intricate coring methodsavailable with other techniques. Otherresearch undertaken at the Foundry Instituteincludes infiltration of metal foams, whichmay be produced by inserting the foam intothe die cavity and then filling the holes bymeans of infiltrating with semi-solid slurry orotherwise, thereby producing very complexhybrid composite metallic materials (seeExhibit 3.9).

3.7 Gravity casting

Gravity casting provides a very good means of producing many complex castingsthat are demanding in terms of bothperformance and weight. This method also provides a low-investment route forsingle-piece or small-lot production that isideal for many aerospace castings.

3.8 Sand casting

GKSS has been investigating issues withsand casting, particularly the issue of meltoxidation or of its alloying elements. A range of casting alloys has beeninvestigated, including AM100, AZ91, AZ81, AZ61, AZ63 and rare-earth alloys. The solutions to reduce moisture andatmospheric reactions include:

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Exhibit 3.8 Thixocasting facility at the Foundry Institute

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• Sulphur and boron acid• Ammonia salt and silicofluoride• Boron hydrogen acid and its salt solutions• Diethylene glycol• Beryllium

3.9 BCAST rheo-diecasting

(RDC) process

Putting the UK into the context of Europeandevelopment of novel magnesium castingtechnologies, we find that the UK strengthlies at the heart of technological innovation.In recent years, the Brunel Centre forAdvanced Solidification Technology (BCAST)at Brunel University has developed a novelsemi-solid casting process, rheo-diecasting(RDC), Exhibit 3.10. The RDC process is aninnovative one-step SSM processingtechnique to manufacture near-net-shapecomponents of high integrity directly fromliquid alloys. The process innovatively adaptsthe well-established high-shear dispersive

mixing action of the twin-screw extruder tothe task of in-situ creation of SSM slurrywith fine and spherical solid particles,followed by direct shaping of the SSM slurryinto a near-net-shape component using theexisting cold-chamber die-casting process.

The RDC equipment consists of three basicfunctional units: a twin-screw slurry maker, astandard cold-chamber HPDC machine and acentral control unit. The twin-screw slurrymaker has a pair of co-rotating, fullyintermeshing and self-wiping screws rotatinginside a barrel. The screws have speciallydesigned profiles to achieve high shear rateand high intensity of turbulence. During theRDC process, a predetermined dose of liquidalloy from the melting furnace is fed into theslurry maker. The liquid alloy is rapidly cooledto the SSM processing temperature whilebeing mechanically sheared by the screws,converting the liquid alloy into semi-solidslurry, with fine and spherical particles of a

Exhibit 3.9 Magnesium-MMC infiltrated foam

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given volume fraction dictated by the barreltemperature. The semi-solid slurry is thentransferred to the shot chamber of the HPDCmachine for component shaping. After sixyears’ intensive R&D, the RDC process isnow ready for industrial exploitation,supported by the DTI Technology Programme.

The main advantages of the RDC processover the conventional HPDC process can besummarised as follows:

• Fine and uniform microstructurethroughout the entire component

• Close-to-zero porosity (well below 0.5 vol%), thus fully heat-treatable

• Well-dispersed oxide particles with finesize and spherical morphology

• Much improved mechanical properties,particularly ductility

• Capable of processing wrought alloys andother alloys difficult to cast

• Longer die life, lower scrap rate, shortercycle time and higher materials yield

• Lower overall component production cost• Weldable

Compared with other SSM processingtechniques, the RDC process is characterisedby high and consistent component quality,large processing window, versatile to alloycompositions, and low overall productioncost. It is anticipated that the RDC processwill become a major production technologyfor light metal components.

3.10 Casting alloy development

A number of magnesium alloy systems havebeen developed for different forms ofcasting to maximise both castability and in-service performance. Four key alloy systemsare available for die-casting, and the outlineadvantages and disadvantages of these areshown in Exhibit 3.11. Particular performancerequirements include improved creepresistance, improved ductility, and improvedspecific strength, and some of theassociated alloys developed are shown inExhibit 3.12.

High-speed

injection unit

Twin-screw extruder

Inlet

Heated shot

sleeve

Exhibit 3.10 Rheo-diecasting (RDC) process

Over the last 10 years there has beensignificant R&D for various HPDC alloys, andthe evidence of this is demonstrated by thenumber of alloy/alloy-modification patentsfiled. The time lapse between patenting analloy to commercial application can be some

8-10 years or even more. Therefore, many ofthe alloys patented over the last decade may find themselves in commercialapplication over the coming years, and manyof these are being evaluated in EU appliedresearch programmes.

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ASTM alloy designation AZ AM AS AE

Key alloying elements Al, Zn Al Al, Si rare earth

Advantages Good strength Improved ductility Improved strength Good high-temperature

at room over AZ series and creep strength and creep

temperature performance due to resistance due to

Good castability Mg2Si precipitates Mg-RE precipitates

Disadvantages Low thermal Limited room Limited castability Limited castability

strength temperature

Low ductility properties

Limited castability

Exhibit 3.11 ASTM magnesium die-casting alloy systems and relative performance

Mg-Li-X

Mg-Si

Mg-Al-Ca(-RE)

Mg-Zn-Cu

Mg-Si

Mg-Al-Ca (-RE)

Mg-Li-X

Specific strengthLight, high strength

Alloy development

DuctilitySpray forming

TMT, MgLi

Creep resistance(monolithic)

Magnesium

Mg-Al-Ca-X

Mg-RE-Zn-Mn

(max 200ºC)

Mg-Al-Zn

AM60 AZ91

(max 135ºC)

Mg-Al-Si

AS 21

(max 150ºC)

Mg-Al-RE

AE42

(max 175ºC)

Mg-Ag-RE-Zr

QE22 EQ21

(max 200-250ºC)

Mg-Y-RE- Zr

WE54 WE43

(200-300ºC)

Mg-Sc-X-Y

(>300ºC)

Fibre and hybrid

reinforced Mg-alloys

Creep resistance(heterogeneous)

CTE

E-modulus

Creep

KEY

GRAVITY

HPDC

WROUGHT

Mg-Al-Mn

Mg-Al-Zn

Exhibit 3.12 Performance drivers for magnesium alloy development

3.11 High-pressure die-casting alloys

and key development drivers

Initial magnesium high-pressure die-castingshave found themselves in relatively benignapplications where weight reduction was themajor factor. Following these, applicationswhich involved increased levels offunctionality were taken up. Subsequently,components that made considerable use ofthe load-bearing capability of magnesiumalloys have been fielded.

A significant area for potential future growthof magnesium high-pressure die-castings isin powertrain and new drivetrain applications,the latter particularly in higher operatingtemperature automatic transmissions,following a degree of saturation in theapplication of structural castings. Newapplications are heavily dependent upon thedevelopment of new and improved alloys,and this is particularly true of the structuralcastings, which are now dominantlyproduced from the AM series alloys, whichdisplay greater levels of elongation thanAZ91. In terms of powertrain and automatictransmission housing applications, theoperating temperature has been the greatestbarrier to growth. The reason for this hasbeen the creep behaviour of commonmagnesium alloys.

The common magnesium alloys displayinferior creep load characteristics incomparison with aluminium alloycounterparts. Above ~100ºC, the commonmagnesium alloy AZ91 begins to lose itsstrength, which has eliminated magnesiumfrom these types of application to date asno economical alloy provided adequatecreep performance. More importantly,AZ91D displays particularly high levels ofcreep strain under load. The major issue forcreep deformation is a reduction in theclamping load of the bolts for atransmission housing, which if relaxedallows transmission fluid to escape.

The highly creep-resistant rare-earth alloysystems, such as WE42 that had beenspecially developed, remain too expensive forthe automotive market. Thus extensiveinternational research efforts have set aboutestablishing lower-cost, creep-resistant alloysdisplaying suitable castability, in terms ofboth good die-filling characteristics and theabsence of hot cracking. Generally, the mostcreep-resistant rare-earth alloys displaypoorer castability, and are therefore lessacceptable for high-volume series production.In close cooperation, Volkswagen (VW) andthe Magnesium Research Institute (MRI)have developed two castable creep-resistantalloys, MRI-153M and MRI-230D. Thesealloys possess great potential for lightweight,high-performance transmission housings andcrankcases as they possess good residualstrength at temperature combined with lowcreep-strain.

A major recent introduction in the field ofautomatic drivetrain applications is theMercedes-Benz 7G-Tronic, 7-speedautomatic transmission housing. The die-casting makes use of a magnesium alloybased upon the AS31 (Al-Si) system.

The major challenges for powertraincomponents still remain in developingcapabilities for crankcases. In theseapplications, the issue is not only one ofcreep resistance but also one of stiffness,and magnesium’s lower modulus alsocreates additional challenges to overcome.However, development trials have takenplace, and Australian Magnesium Corp Ltd(AMC) and its partners have developed andpatented a new creep-resistant alloy AMC-SC1 which has been specifically designedfor the production of lightweight engineblocks using sand-casting technology. The alloy has already been used to build aprototype 3-cylinder engine for a VW Lupo,weighing just 14 kg – 25% lighter than thecurrent aluminium production version. AVLdesigned the new magnesium engine,

20


which catered for its different mechanicaland acoustic properties. Further to this,BMW Group has now put into productionmagnesium HPDC crankcases in its V6engines, which make use of aluminiumcylinder linings. This application is a worldfirst on the basis of a water-cooled high-performance engine. The actual cooling isrestricted to the aluminium cylinder liners.The BMW HPDC magnesium crankcaseuses the Noranda-developed AJ62 alloy.Similar developments are expected.

Magnesium Elektron in the UK has beenheavily involved in alloy development,particularly with Manchester University, and also supplies the AJ62 alloy to BMW for the magnesium crankcase.

3.12 Gravity casting

alloy development

Whilst there has been significant impetus todevelop alloys for die-casting, gravity castinghas assisted in providing the foundation onwhich more recent creep-resistant alloyshave been developed. High-performancemagnesium gravity castings for aerospaceapplications see much greater operationaltemperatures and have driven thedevelopment of automotive creep-resistantalloys. The success of the rare-earth alloys islargely owed to the complex precipitates

that form, inhibiting creep deformation. The success of these alloys for theseapplications is also attributable to the castingprocess, that is more tolerant to defects,namely entrapped porosity.

3.13 Other casting

technology research

In addition to the development of magnesiumalloys and new casting technologies forcomponents, new environmentally friendlyproduction methods and means of improving billet and ingot have been soughtand researched.

A major issue that faces magnesium foundriesis the requirement to change to moreenvironmentally friendly and inert systems toprotect the magnesium melt. Consequently,there has been much focus on using CO2 orother systems, as opposed to SF6 and SO2.However, improvements in the gases not onlyrequires just a simple change in the cover gasmedium used, but also requires developmentin how it is administered. In particular, coolingdown the melt surface to avoid evaporation,and also controlling the displacement ofoxygen by means of a CO2 ‘snow shower’(see Exhibit 3.13). Other means of meltprotection under investigation include the useof a layer of steel balls covering the top of amagnesium melt.

21


CO2 -snow laboratory furnace Covering of molten magnesium with

CO2-snow

Exhibit 3.13 CO2-snow magnesium melt cover gas development

22


Exhibit 3.14 Magnesium up-caster used in EUROMAGUPCASTER

Exhibit 3.15 Magnesium foam production by low-pressure die-casting (LPDC)

Discharge direction

Solidified magnesium

Mould

Liquid magnesium

23


New methods for improving componentquality through improved alloy casting havebeen investigated, including twin-roll castingfor sheet and up-casting of billet. The up-casting of magnesium is being conducted aspart of the EU programme calledEUROMAGUPCASTER, the aims of whichare to obtain improvements over the verticaldownward casting (VDC) method, including:

• No risk of MMW (molten-metal-water)and H2 explosions in secondary cooling zone

• No contact of molten magnesium to atmosphere

• No protection gas needed for casting process

• Self-regulating: melt-level control in themould is not required

• Billet surface free of cracks and other defects

• Easy installation

Initially, this project included developmentsto engineer a prototype to produce 90-mmbillets at Hannover University’s IW (Institutfür Werkstoffkunde), and subsequently twopilot devices for 90-mm and 203-mm billets.During the EU project it was planned thatprocessing conditions for the following alloyswould be developed:

• AZ31• AZ61• AZ80• AZ91• ZK60• WE43

The basics of this technology are obvious, in that the material is cast in the upwarddirection (see Exhibit 3.14). Other keyelements of the research scope included inthe EUROMAGUPCASTER project include theinvestigation of costs for industrial usage andevaluation of wear on the moulding system,which is a critical factor in maintainingconsistency in the process and also costs.

Germany is a world leader in thedevelopment of metal foams, and is activelypursuing improvements in the technology,performance and potential application. The aim is to improve the productionefficiency and costs associated with themanufacture of magnesium foams,particularly as the current means of foamproduction are too expensive for volumeproduction. Therefore, Hannover has beeninvestigating the use of low-pressure die-casting (LPDC), which may significantlyreduce the costs – and also repeatability – of metal foams (see Exhibit 3.15). Metalfoams may have significant capability inenergy-absorbing crash-relevant structures.Such improvements in cost may thereforelead to introduction in automotiveapplications. Additionally, it should be notedthat IFAM have recently acquired an HPDCfacility from Oscar Frech GmbH, and areproactively exerting effort to create a well-equipped foundry research centrecovering all aspects of casting, from sand tohigh-pressure techniques.

In terms of UK activity, in addition to RDCtechnology, the UK is also pioneering theinvestment casting of magnesium alloys,with this research being conducted atCastings Technology International (CTI).However, the funding for casting R&D in theUK is considerably smaller than that madeavailable in Germany, which is reflected inthe degree of activity in this field.

3.14 Summary

The general finding from the mission is thatin the future there will be a continuousincrease in applications of cast magnesiumcomponents in the automotive industry andother industrial sectors, such aselectronics, healthcare, and sports andleisure. Such applications were heavilysupported by both alloy and processdevelopments to encourage growth for themagnesium industry.

24


In Europe, research into novel castingtechnologies is well supported and wellcoordinated, using both internal government-funded and EC framework programmes,such as MG-CHASSIS, RHEOLIGHT and MG-ENGINE. The drive for most of these hasbeen the realisation of component orsystem performance improvements. Theseprogrammes constructively take the castingtechnology through to the evaluation ofdemonstrator components and applications,linking state-of-the-art alloys. Consequently,there is an abundance of technologies anddevelopment alloys, enabling early marketentry of a number of exciting high-performance products. The UK has very littleparticipation in such programmes, and theapplication of magnesium technologyreflects this.

The general understanding is thatrheocasting processes have some majoradvantages over thixocasting andthixomoulding processes in terms ofproduction cost, component quality,production control, and flexibility.

The rheo-diecasting (RDC) processdeveloped in the UK does have advantagesover the other casting technologies underdevelopment in Europe, such as high andconsistent component quality, largeprocessing window, versatile to alloycompositions, and low overall productioncost; and with technology that appears to besuitable to scale-up.

R&D on magnesium alloy casting isconsiderably underfunded in the UK,particularly when compared to the activitiesin Germany. There is great need for acoordinated magnesium flagship project torealise the full potential of the UK forcasting technology innovation and toincrease the critical mass for participation inthe EU programme.

25


Casting of magnesium is a very economicprocess, particularly die-casting, and suitablefor mass-volume component production, but even at low volumes it also providessubstantial opportunity to integrate one ormore parts together and produce withcomplex geometries. However, due toresidual porosity, wrought magnesiumproduct forms often provide more favourablemechanical properties in terms of strengthand elongation. There are four key forms ofwrought magnesium: magnesium sheet andplate, extruded profile, or forged billet.

Unlike magnesium castings, wroughtmagnesium has historically receivedconsiderably less R&D for componentapplications, as it represents considerablyless market share in terms of total globalmagnesium consumption, typically lessthan 1-2%. Consequently, there are veryfew commercially available alloys, with themain alloy AZ31 dominating production.Those alloys commercially available havealso not necessarily been developed withspecific product applications in mind.

For the automotive industry, the majoropportunities for wrought magnesium are inbody and chassis applications, and to aconsiderably lesser extent powertrain, due

to the complexity of the components. The body structure and closures contribute~40% of the mass of a vehicle. The greatestopportunity for wrought magnesium is inreplacing components within the primarystructure. However, opportunities for interiortrim and closures also exist.

As mentioned, semi-finished magnesiumproducts only account for some 1% of totalconsumption of magnesium, which in turnrelates to limitations in supply availability.

4.1 Extruded magnesium profiles

Critical success factors in the growth of themarket for magnesium extrusions are thedevelopment of new alloys, an optimisedbillet casting process to produce animproved starting product for extruding, andlower extrusion costs. The greatest issue inprocessing extruded magnesium is in theexit speed with which it may be produced.This in turn influences the price of the semi-finished product, which to date hasbeen excessive. VW has indicated that toincrease the use of extruded magnesium invehicle manufacture, a target price of theextruded product should be of the order of€5-8/kg in comparison with the currentprice of €10-20/kg.

4 DEVELOPMENTS IN PROCESSING AND MANUFACTURE

OF COMPONENTS FROM WROUGHT MAGNESIUM

Formability

Limits

Hot

Cracking

Billet Temperature

Safe

Processing

Exhibit 4.1Process window for indirectextrusion of AZ31

Billet temperature

Extr

usio

n s

peed

Hot cracking

Safe processing

Formabilitylimits

Hotcracking

26


The major factor in lowering the cost isrelated to the extrusion speed. Currently, the exit speed for magnesium AZ31 is 20-30 m/min. The extrusion speed is limitedby the onset of hot cracking and formability(see Exhibit 4.1). Therefore, a major EUresearch project, MAGNEXTRUSCO, wasinitiated to engage the issue of extrusionspeed and also post-processed properties forforming and in-service performance. The research project was to investigate thecapability of the hydrostatic extrusion processfor magnesium alloys (see Exhibit 4.2) inorder to achieve greater extrusion speeds,fundamentally necessary to improve theprocess economics to compete withaluminium alloys, which typically possessextrusion speeds of some 50-100 m/min.

Hydrostatic extrusion speeds for magnesiumalloys of the order of 200 m/min are possiblebut will also necessitate alloy developmentto widen the safe processing window. The key requirements here are to developextrusion billet material with greater levels

of grain refinement, typically 50-200 µm, and improved microstructural uniformity. These are key factors that influence theprocessing mechanics. In particular,microstructural uniformity is particularly poorin magnesium billet.

The type of extrusion process is particularlyimportant, as are the key process variablesof temperature, extrusion ratio and extrusionspeed. The aim in controlling theseparameters is to enable the highestthroughput possible whilst meeting therequired mechanical properties. This can onlybe achieved by producing homogenousmicrostructures that are stable torecrystallisation dynamics during theextrusion process. GKSS has been heavilyinvolved in the characterisation of themicrostructural and mechanical propertiesand deformation mechanisms of theextruded product. Much of this work hasbeen part of the MAGNEXTRUSCOprogramme, but also in support of the VW 1-litre lightweight concept car.

Die

Extrusion press

Ram

Extruded profile

Billet

Hydrostatic mediumSeal Seal

Exhibit 4.2 Hydrostatic extrusion process

27


4.1.1 ‘Take-Off’ (aerospace) project

LKR conducted a research study calledTake-Off, which investigated the opportunityfor substitution of a 1.6-mm thick 6XXXseries aluminium alloy extrusion withmagnesium AZ31 extrusion, whilstmaintaining equal stiffness and a weightsaving of 15%. The application in this casewas for passenger stowage unit (PSU) rails,located underneath the stowage lockers(see Exhibit 4.3).

During this investigation, LKR studied,evaluated and refined the product design,and performed finite element analysis (FEA)of the extrusion process. This investigationfollowed through to produce prototype AZ31 extrusions, on which LKR performedmechanical and microstructuralcharacterisations. It was demonstrated that, through a new design concept, both the weight and stiffness targets could be achieved.

The orthotropic behaviour of magnesiumextruded profiles, which relates to thetwinning and texture, provided the mainchallenges in the programme. However, withthe development of new alloy systems andthe hydrostatic extrusion process, it isbelieve that there is significant scope toaccelerate the design process due to greaterlevels of confidence in the materialproperties and behaviour.

Following on from these investigations, LKRhas also been reviewing opportunities for a1.0-mm thick PSU rail for the A380 Airbus.

In October 2004, LKR was embarking upona further programme to qualify the suitabilityof magnesium components for aerospaceapplications, in collaboration with otherregional light metals and aerospacecompanies. The programme was calledInnMag and formed Phase 2 of Take-Off.

Original AZ31- AZ31 AZ31 AZ31

AW-6061 Substitution Variant 1 Variant 2 hybrid

t (A1) 1.6 mm 1.6 mm 2.0 mm 1.8 mm 1.6 mm

t (A2) 1.6 mm 1.6 mm 2.0 mm 3.1 mm 1.6 mm

t (A2) 1.6 mm 1.6 mm 2.0 mm 1.6 mm 1.6 mm

E*1 100% 68% 82% 95% >100%

-�m 0% 35% 20% 15% 20%

Exhibit 4.3 LKR Take-Off project: magnesium PSU rail designs investigated

28


4.1.2 VW 1-litre car

The VW 1-litre car is so named because ofits fuel consumption rating of just 1 litre per100 km (equivalent to 282 mpg). Stolfig, theGerman design company contracted toproduce the car, engaged heavily in drawingon the key competencies at LKR to assist inthe development of the magnesiumconstruction, in particular the joining.

Whilst cost is the major issue for extrusions,providing major technical and developmentchallenges, the other key issue withextruded profiles and also sheet magnesiumrelates to the inherent lack of formability ofmagnesium alloys at ambient temperature.This issue cascades particularly intomechanical joining methods such asclinching and self-pierce riveting (SPR) thatmay be selected to join structures together,especially hybrid structures consisting ofdifferent materials.

4.1.3 Formability

In addition to issues relating to extrusionspeed, extruded profiles also require heattreatment to assist in reshaping into the finalproduct form.

According to GKSS, the outcome from theMAGNEXTRUSCO programme was positive,in that the hydrostatic extrusion processproduced alloys under enhanced extrusionspeeds. However, much of the formability

could not be changed, and this purely relatedto physics, ie that magnesium has ahexagonally close-packed structure. Initialtrials using warm hydroforming indicated thatthis technique could be used to reshapemagnesium profiles. Bending of tubularmagnesium profiles is achievable, andheating during bending assists considerably.The necessity to use heating for productshaping creates a potential barrier and maypreclude shaped magnesium profiles fromsome applications, particularly those in whichthe cost outweighs performance needs.

The outcome of MAGNEXTRUSCO alsopointed toward preferred profile geometriesand applications, including:

• Simple sections with limited cross section• Simple 2D and 3D shapes• Potential for non-structural and structural

applications (non-crash relevant parts)

The programme finds that the application ofmagnesium extrusions should not containcrash energy-absorbing components. Thereason relates to the material’s crystalstructure, and lack of available slip systemsto achieve high degrees of deformation.Despite this, there is significant scope forother structural and non-structuralcomponents manufactured from magnesiumextrusions. However, there is a preferencefor producing components from simplesections, in order to minimise associatedmanufacturing costs.

4.2 Sheet magnesium

Currently, the availability of sheet magnesiumis very limited, with only a few pilot-sizeplants. Many of these are not producingproducts specifically for the automotivemarket, much of the end use being forelectrolytic cells or precision machined parts.Additionally, there are only a few availablealloys, and therefore a narrow selection ofstrength and performance options.

Exhibit 4.4 VW 1-litre car, incorporating wrought andcast magnesium

Al-profile

Al-sheet

Mg-profile

Mg-sheet

Mg-casting + machined

MG-casting + part machined

CFK

29


To make matters worse, there is also verylittle supply chain existence or capability toproduce the final components. Therefore,GKSS seized the opportunity to be engagedin a full process chain developmentprogramme for magnesium sheet,extending from alloy development toapplications. This was in the form of ULM, a BMBF project, involving VW, SalzgitterMagnesium-Technologie GmbH (SZMT),AHC Oberflache, LZH, IFUM IW Hannover,Eckold and GKSS.

Sheet magnesium displays strong levels ofanisotropy considerably greater than that ofaluminium. This phenomenon relates to thefact that magnesium has a hexagonallyclose-packed structure and texture shape ofthe basal plane, whereby activation of basalslip in the sheet rolling direction is preferredto the transverse direction. Evidence of thisis displayed in AZ31 tensile tests that showthe rolling direction to have a lower yield andtensile strength (see Exhibit 4.5).

Interestingly, magnesium sheet has someunique mechanical properties, which alsomean that it displays very good dentresistance. The characteristic is attributableto the very low modulus of elasticitycombined with its reasonably high yieldstrength. Therefore, magnesium sheet offersgood potential for exterior panels that mayrequire good dent performance.

Salzgitter Magnesium-Technologie GmbH(SZMT) presented a number of potentialmarket applications for sheet magnesiumand heavy plate, including:

AEROSPACE• Cockpit carriers• Doors • Non-pressurised parts• Secondary structural parts• Seat components• Interior components• Covers, boxes and brackets

AUTOMOTIVE• Closures• Structural parts• Exterior panels • Crash relevant parts

CONSUMER GOODS• Leisure• Electrical equipment (laptop, mobile

phone and camera casings)• Structural parts• Exterior panels • Crash relevant parts

SZMT supplies sheet magnesium between1-4 mm thick and heavy plate 20-100 mmthick. The latter may be used for lightweight,precision-machined products. SZMTsupplies AZ31 sheet magnesium in the soft-annealed ‘O’ condition, the typicalmechanical properties of which aredisplayed in Exhibit 4.6.

Exhibit 4.5 Anisotropy of magnesium sheet AZ31

AZ31-H24 RD

AZ31-H24 TD

AA6016-T4 RD

AA6016-T4 RD

Strain (%)

Str

ess (

MPa)

Sheet quality Soft-annealed ‘O’ condition

Yield strength, Rp0.2 130-160 MPa

Tensile strength, Rm 230-260 MPa

Uniform elongation, Ag 15-17%

Total elongation, A80 17-22%

Thickness tolerance ± 0.07 mm

Exhibit 4.6 Typical mechanical properties ofmagnesium sheet AZ31

30


The small difference between uniform andtotal elongation is a strong characteristic ofthe failure behaviour of magnesium, be itin sheet or extruded product form. Formagnesium alloys, the failure takes placeat maximum load without substantialfurther deformation. The reason for this isthat the material fails in shear, and criticallyit is very different from sheet aluminiumand strip steel. Therefore, there are somevery different requirements in terms of theway failure of wrought magnesium ismodelled in crash or other structuralperformance models. This is an area wheredevelopment is required, and Ford havebeen researching.

SZMT produces standard AZ31 sheet andheavy plate but also speciality alloys. Tocomplement these, and to support thegrowth and development of their products,SZMT will provide product developmentengineering support and produce prototypesfor potential customers.

In terms of manufacturing sheetmagnesium into parts, new or revisedtechnologies are necessary. These includethose used in forming, joining, and incomponent surface treatment. The keyforming processes available include:

• Hot bending• Hot stamping • Superplastic forming (SPF)• Warm hydroforming

In trials conducted by VW, hot-stampedclosure parts were successfully produced,and a number of special lubricantsevaluated. However, from these trials anumber of issues remained to be resolved, including:

• Drawing-fluid deposits left on drawncomponent

• Smoke• Flammability (slithers)

Interestingly, VW had established that thehot-stamping method could also be achievedusing low-cost tooling methods suitable forlow-volume applications. Special plastic orelectroplated tools could replace more costlysteel or grey iron materials. Difficulties withthe hemming were found, due to thereduced formability of the components.

Collaborative trials between IFUM Hannoverand SZMT into hot stamping have beenconducted on some prototype bonnet parts(see Exhibit 4.7) which have successfullydemonstrated this method to be a viable,reproducible technique for the production ofcomponents from sheet magnesium.

Trials conducted by VW have found thatwhilst conventional sheet magnesium formswell at between 200-250ºC, it can be formedat temperatures as low as 150ºC. Atelevated temperature, magnesiumdemonstrates a drawing ratio of 2.6compared with 2.5 and 2.2 for deep-drawingaluminium and steels, respectively. Thedrawing ratio is a statement of formability.The greater the value of drawing ratio, thegreater the material formability. Therefore,hot stamping exhibits good performancepotential for limited-volume manufacture.

Superplastic forming of magnesium alsoshows promise. However, it is likely toremain a viable production process for very-low-volume, luxury and performance nichevehicles seeking performanceenhancements through weight reduction.Again, the current sheet magnesium prices

Exhibit 4.7 Hot-stamped magnesium prototype parts(SZMT and IFUM Hannover)

31


prevent or inhibit increased application infavour of superplastic forming of aluminiumsheet. This issue can only be resolvedthrough reductions in alloy cost and throughmajor improvements or developments in thesheet production processes.

4.2.1 Future development requirements

Besides improving the availability ofmagnesium sheet at competitive costs, thefollowing areas of significant developmentare required to achieve greater levels ofimplementation readiness:

• Surface roughness characteristics (Ra and peak count) for optimallubrication, corrosion protection and paint finish

• Corrosion performance and surface treatments

• Quality (reproducible properties and dimensions with acceptable tolerance bands)

A number of these requirements are likelyto take considerable R&D efforts. A BMBF research programme examiningthe tribology developments during rolling ofmagnesium sheets is being conducted atHannover University, under the title ULM(‘Ultralight Parts Made from Mg Sheets’). The aim of this research is to achieve better surface qualities in sheet magnesiumproducts (see Exhibit 4.8).

The major requirements of lubricants forrolling of magnesium sheets include:

• Prevention of sticking• Generation of optimised surface

roughness for coatings (including paint)• Enhanced corrosion resistance

by passivation

To achieve these targets, there are three key approaches:

• Lubricants• Coating of rolls• Optimisation of sheet rolling cycles

Exhibit 4.8

Influence of lubrication on rollingmagnesium sheet

withoutlubrication

optimisedlubrication

32


However, it would appear that mill roll texturedevelopment was currently not a majorfeature of this research. It would thereforeappear that the research was to rapidly assistin product development of magnesiumsheets produced using current technologiesand methods as opposed to long-term, morecapital-intense developments.

4.3 Forged magnesium

GKSS is involved in EU programmeMAGFORGE, which is under way. Thisprocess route is a very strong opportunityfor chassis components. Exhibit 4.9illustrates a forged magnesium part atvarious stages between initial billet andformed part.

Considerable development of the alloys andprocess will be required to achieve suitablecomponents, particularly as currently thefatigue life of magnesium components islower than that for aluminium. For chassiscomponents, both forged and rheocastmagnesium provides greater opportunity, asthese product forms may be weldable andheat treatable.

However, actual implementation of these forcomponents may be some years off. Thereappears to be much work still to be done inthis field, and uptake will be difficult forsafety-critical chassis parts in vehicles,particularly until the price for wroughtmagnesium becomes agreeable.

Exhibit 4.9 Forged magnesium demonstration parts

33


The joining and integration of magnesiumcomponents is a key area of research, as the ability to integrate considerably more magnesium into the vehicle is heavily dependent upon the successfuldevelopment and implementation of these.

The following are key issues for joining and integration:

• Selection of joiningtechnology

• Joint and assembly qualityand performance

• Production volumes, processefficiencies and cost

• Maturity of joiningprocesses (including modelsof failure behaviour)

• Corrosion (galvanic) issuesfor joint or other materialinterfaces

• Surface treatments and theirspecification

• ELV directive

Beyond weight reduction, amajor benefit of the castingprocess is the ability and easewith which parts may beintegrated into a singlecomponent design, therebyincreasing the partfunctionality, and potentiallyboth cost and performance. A considerable part reductioncan be achieved over manyconventional steel oraluminium fabricated designs,and many different functionsand features achieved in thesingle die-casting, as illustrated

in Exhibit 5.1. Features such as radiosupports, poke-yoke features andmounting/securing features that wouldotherwise require a number of parts in anassembly, may easily be integrated at littleadditional cost when designed for.

5 JOINING TECHNOLOGIES

AND INTEGRATION

Exhibit 5.1 HPDC cross-car beam displaying high levels of part andfunction integration

34


In terms of high pressure die-castings, thesehave restricted mechanical properties largelydue to entrapped porosity. This is not anissue for wrought products. Such entrappedporosity in a casting not only influencesmechanical properties but also the ability tocreate assemblies in subsequent welding orjoining processes.

In terms of the vehicle, the key areas for magnesium implementation include the following:

• Body (structure and interior trim)• Powertrain• Chassis

Joining and integration are particularlyimportant aspects, and this is why there issuch an interest and focus in this field,essential to producing component systemsor assemblies of high integrity. Particularlyfor body and chassis applications, joining is akey enabling technology. Whilst magnesiumalloys may be found in vehicles, theygenerally are in applications where they arerelatively benign to the remainder of thestructure or vehicle, and typically usemechanical fasteners to integrate them withthe remaining structure.

The possible scenarios for inclusion ofmagnesium components into a futurevehicle body structure include:

• Magnesium-intensive body structure• Hybrid body structure

The latter is more likely but will largelydepend upon continual R&D and futurelegislation.

However, to date the integration ofmagnesium into the structure of a vehiclehas been relatively limited. In the majority ofstructural applications, magnesium has beenin the form of HPDC cross-car beams andseat frames, which include their own

integration issues. However, these challengesare by no means on the same scale as wouldbe required components for body structures.

Aside of some of the mechanicalperformance requirements, the mainreasons for this limited scope of applicationcan be attributed to a lack of wroughtproduct availability in suitable quality andappropriate cost for economic, mass-volumemanufacture. This is also coupled with aconsiderable lack of design knowledge,particularly in terms of simulation capabilityto predict magnesium component or system performance.

A BMBF research programme called InMaK,between the following research partners,has addressed some of these issues:

• Laser Zentrum Hannover• Hannover University• Ford Forschungzentrum • Honsel• Elisental (aluminium and magnesium

products)• EADS

The InMaK programme was aimed atidentifying improved alloy quality and extrusioncapability but also included the developmentof laser and MIG welding processes and theability to predict failure under loading, usingnumerical simulation techniques. This wasachieved by investigating the structuralperformance of magnesium intensivestructures (see Exhibit 5.2).

This programme appeared to link with Ford’smagnesium-intensive B-class concept vehicle.

In addition to the InMaK researchprogramme, joining technology for wroughtmagnesium is a major interest and, aside ofalloy development, joining remains a keyenabling technology for the future growth ofmagnesium for automotive and otherindustry sector applications.

Some of the available techniques for joiningof magnesium include:

• FSW (friction stir welding) • LAFS (laser assisted friction stir) welding• RSW (resistance spot welding)• MIG (metal inert gas) welding• TIG (tungsten inert gas) welding• Laser welding• Magnetic pulse welding• NVEB (non-vacuum electron beam) welding• SPR (self-pierce-riveting) • Clinching• Adhesive bonding• Fasteners (bolts, screws,

thread-forming screws)

However, a number of these remain verymuch at the development stage, and requirefurther research to become more matureand gain acceptance or are shelf-engineeredready for implementation. Only processessuch as TIG and MIG techniques andfasteners are fully mature.

The principal focus of research intomagnesium joining technologies is toestablish suitable process parameters for

the likely alloys and product forms andrespective joint conditions. Much of theactivity has been focused on the fabricationcapability of demonstration parts or systemsmade from wrought components,particularly extrusions and sheetmagnesium, with joining of sheet to sheetand extrusion to extrusion used to assimilatefinal components.

5.1 Laser welding

Much of GKSS’s research activities are inFSW and laser welding, and mechanicaljoining and adhesive bonding. Theseactivities feed back to alloy developmentactivities and design guidelines.

The laser welding activities at GKSS includeboth aluminium and magnesium welding. Inthe magnesium welding trials, GKSSidentified a number of key characteristics inlaser butt-welding magnesium alloy sheetmaterial. For AZ31:AZ31 laser-welded joints,the weldments do not possess graincoarsening adjacent to the fusion zone (seeExhibit 5.3). This finding is corroborated bywork done at LKR.

35


Exhibit 5.2 InMaK: applied research into themanufacture of magnesium structures

Base metal Fusion zone

Exhibit 5.3 Laser welding of magnesium sheet: AZ31 (2-mm thick), 7 m/min, 3.3 kW

Coarse grainedparent material

Fine grainedfusion zone

No grain coarseningadjacent fusion zone

GKSS also found that the size anddistribution of porosity in the weld wasvery heavily influenced by the weldingspeed, and optimal speeds of 7-10 m/minare possible in 1-mm thick AZ31, withoutthe assistance of welding filler wire. This proves that magnesium can be readilywelded at suitable speeds for volumemanufacture. Other welding trials illustratethat magnesium could be manufactured asa tailored blank concept to optimise forperformance by selection of appropriatematerial thickness and properties and their location.

In LKR’s laser butt-welding trials, extrudedmagnesium alloy AZ31 B-F was capable ofbeing welded at 13 m/min at a power of 3.3 kW for 1.5-mm, 2.0-mm and 2.5-mmthick samples. The physical nature of thelaser-welded magnesium samples displayeda very fine ‘partially melted’ zone (PMZ) andno heat-affected zone (HAZ). Argon gasshielding was used. In the absence of filler,the welds displayed slight undercut. One ofthe issues anticipated was hot cracking;however, this was not found to be a majorissue with laser beam welding.

5.2 Friction stir welding (FSW)

In GKSS’s welding department, FSW isperformed using an FSW robotconfiguration. This enables considerableflexibility in terms of the joint type andparts that can be welded, when comparedwith a standard mill-like FSW machine.GKSS has found that, in FSW joints inAZ31-AZ31 magnesium sheets, the weldhas little impact upon the mechanicalproperties. A small increase in hardness isexperienced, but little variation across theweld from parent material to parentmaterial. The Al:Mg FSW welds displayed a greater degree of variation in properties, as would be expected. In terms of fatigueperformance, the Mg:Mg FSW sampleshad a similar performance to the Mg:Al

FSW but were considerably lower than theAl:Al. The FSW process appears to be verytolerant to different material combinations,including magnesium to aluminium joints(see Exhibit 5.4).

5.3 Mechanical joining

In terms of these technologies, the followinghave received the greatest focus as they areseen as essential to reducing the cost ofcomponents:

• SPR – cold (optimisation of rivetgeometry and process)

• Clinching – elevated temperature• Hemming/seaming – elevated temperature

The mechanical joining of magnesium viaSPR, clinch or hemming processes causesmajor challenges in that the formability ofmagnesium is poor at low temperatures.However, elevating the temperature has aknock-on effect of increasing product cost.Therefore, if any suitable means can befound by which these joining processes canbe made more economically viable, thegreater the chances of up-take.

Both IFAM and LKR have been involved inresearch trials to optimise the geometry ofself-pierce rivets and develop the process sothat it may be achieved at ambienttemperatures. According to LKR, thereappears to have been some success in this,and a major factor in the joining development

36


Exhibit 5.4 Friction stir welded (FSW) Mg and Mg:Al sheets

Mg-Mg dissimilar FSW

Al-Mg dissimilar FSW

AZ31

AZ31 AC120

AZ61

is the generation of numerical models of theprocesses, as shown in Exhibit 5.5,demonstrating a more economical means ofproducing this type of joint. However, someconstraints have been found, and furtherdevelopment is necessary.

VW has found that riveting magnesium toaluminium is possible by using semi-tubularrivets, and achievable at room temperatureprovided that the aluminium is placed ontothe bottom die. Such a joint configurationmay be typical of what could be expected in a potential future closure system or body structure assembly.

VW has also been involved in the successfuldevelopment of heated seam joints orhemming for the hood closure system on the3L Lupo. The heating fulfils two purposes: it provides enhanced formability of thehemmed joint and also cures the adhesive.However, particular attention to detail interms of the passivation treatment is critical.

5.4 Resistance spot welding (RSW)

LKR is also involved in research into RSW of magnesium sheet in addition to high-strength steel and aluminium, with cost amajor motivator. Much of this developmentis achieved through numerical simulationtechniques. However, this weldingtechnology is not a major focus comparedwith other joining technologies.

5.5 Co-extrusion

LKR has also actively researched co-extrusion, a means of metallurgicallybonding two or more alloys by simultaneousextrusion (see Exhibit 5.6). The purpose is toachieve selectively tailored performance, eg stiffness, strength, wear, chemicalresistance, optical appearance.

37


Exhibit 5.5

Cold riveting of AZ31extrusions, and finite elementprocess simulation

Exhibit 5.6 LKR co-extrusionresearch

5.6 Mechanical fasteners

MPI has tackled some of the moreconventional but no less important areassuch as the common attachment screw forassembly of the interior trim to theinstrument panel beam, for example. It hasbecome increasingly common in recentyears to use steel threaded inserts inlightweight materials due to their inability tocope with the requirements for re-insertionor serviceability (see Exhibit 5.7).

Constant insertion and extraction of thescrew would generally degrade the thread inthe light metal and render it useless as anattachment. Steel inserts provide a stableplatform for the thread to engage and re-engage several times.

However, the major drawback with thismethod is the issues that can arise with theinsert spinning in the aluminium ormagnesium metallic carrier metal. There canalso be an issue with assembly torque onthe guns used at the OEM or Tier 1integrator. The torque range must berestricted, and this sometimes requiresmore diligence than usually desired. As aconsequence, great strides have been madeat some fastener suppliers in manufacturinga screw which forms the thread within thecasting and provides an excellentserviceability record for re-insertion. This isnow offered as a robust solution whenattaching to magnesium (see Exhibit 5.8).

This solution performs very well in all testsfor pull-out force and assembly ease. The torque settings are still an importantassembly requirement but the advantagesfar outweigh this.

Many assembly lines continue with thefrustration of spinning riv-nuts and riv-serts,but there are thread-forming screws that canperform admirably against any steel screwand do not require steel at all. The threadforming screw option is offered to Meridian’scustomers in their magnesium HPDCcomponent designs.

There are many other areas of advantage inthe use of these screws, and theenvironmental one is important and willbecome more advantageous in the future, asenvironmental pressures become even moreintense. When recycling the lightweightmaterials with steel inserts, the grade ofmetal would either be downgraded and thesteel taken out during the melt, or the steelinserts would have to be removed prior tothe melt to make it a higher grade scrap part.With the use of thread forming screws, asthe fitted components are removed we havea purely magnesium alloy component whichis 100% recyclable with ease.

38


Exhibit 5.7 Conventional steel threaded insert usedwith magnesium HPDCs

Exhibit 5.8

New thread-formingscrew for fastening tomagnesium castings

Some very interesting research at HannoverUniversity includes the use of diffusionbonding to encapsulate threaded inserts intometal foams, whereby magnesium foamsurrounding the threaded insert is diffusedinto the aluminium foam, as shown in Exhibit5.9. This joint enables connectivity of thestructural foam to another foam or structure.

39


Exhibit 5.9 New metal foam threaded-insert technology

Heat radiation1 2 3

1 Aluminium foam2 Thread bush3 Foamable magnesium

40


6 MAGNESIUM SURFACE

TREATMENTS

The corrosion resistance of magnesiumcomponents depends upon similar factorsthat are critical to other metals. However, dueto the electrochemical activity of magnesium,the relative importance of certain key factorscan greatly amplify the propensity by whichmagnesium may corrode.

The electrochemical activity of magnesiumalloys and their corrosion behaviour has longbeen an issue and was partly the cause of areduction in their utilisation in manyaerospace applications. The original poorperformance of these early alloys waslargely attributed to heavy-metal impuritiessuch as iron, nickel and copper. Modern‘high-purity’ alloys do not suffer from thesame issue, as illustrated by the differentcorrosion rates between AZ91C and high-purity AZ91E (see Exhibit 6.1).

This demonstrates that modern magnesiumalloys have similar salt-spray corrosionperformance to aluminium alloys. Four mainelements (iron, nickel, copper and cobalt)have extremely deleterious effects on thecorrosion performance of magnesium

because of their low solid solubility limitsand their ability to serve as active cathodicsites for the reduction of water, at thesacrifice of elemental magnesium. It isbecause modern high-purity magnesiumalloys have much lower concentrations ofiron, nickel and copper that the corrosionperformance is considerably improved.

What complicates the use of magnesiumalloys, however, is the electrochemicalactivity. For some component applicationsthere is a requirement for appropriatecoating systems to prevent or reducegalvanic corrosion effects by means ofpassivation, making the magnesium surfacemore inert. Such a coating or surfacetreatment may be supplementary to anyaesthetic coating requirement.

The development of new surface treatmentsand coating technologies for magnesiumcomponents is therefore essential to enablewidespread use of magnesium alloys toachieve lighter, more fuel-efficient designsfor transport components.

100

200

300

400

500

600

700

800

900

1,000

1,100

C 355

A 356

A 357

A 201

A 203

A 206

WE 43

WE 54A Z91E

A Z91C

ZE 41

QE 22

Elektron 21

AS

TM

B11

7 S

alf

fo

g c

orr

osio

n r

ate

(m

py

)

Exhibit 6.1

Corrosion performance ofvarious magnesium andaluminium alloys

41


The other major driver for the developmentof new coating technologies or new coatingsystems is to achieve new environmentallyfriendly systems in accordance withlegislation such as the EU end-of-life vehicle(ELV) directive (EC 2003/53). Such newcoating systems must also be economic,whilst displaying equivalent or bettercorrosion performance and/or wearresistance. For automotive applications, theuse of hexavalent chromium and otherheavy metals has been prohibited throughthe ELV directive. Therefore, automotivemanufacturers are required to usealternative coating systems, some of whichmay be inferior for the equivalent cost, ormore costly in delivering equivalent orbetter performance.

Importantly, also, the new coating systemsmust provide for good adhesion, particularlywhere adhesive bonding is used as a meansof joining components together.Breakthrough of the coating could havedisastrous effects on the performance of thejoint, and possibly lead to failure.

6.1 Mission objectives (surface

treatments)

• Investigate the state-of-the-art ofEuropean surface treatments

• Identify potential new applications formagnesium, particularly those wheresurface treatment is critical to its successor failure

• Identify areas where the use ofmagnesium is being limited by lack ofsuitable surface treatment

• Observe how seriously the Europeanssee surface treatment as an issue

• Identify potential partners for UKcompanies and DTI investment projects

6.2 NANOMAG

A major EU programme called NANOMAG hasbeen undertaken to investigate four candidatetechnologies that may enter the coatingsmarket of the future for use with magnesiumalloy substrate components. The three-yearprogramme that started in April 2002 aims todevelop optimised coatings specifically fordifferent applications, and investigates wear,

Exhibit 6.2

PAPVD coating process

V

V

Ar

V

Closed-field

power supply

Sputter power

supply: bipolar

pulsed DC

Substrate bias:

bipolar pulsed DC

Cathodic arc evaporation

Power supply: bipolar

pulsed DCWork

piece

V

42


QuickTime™ and a

decompressor

are needed to see this picture.

OCH3

OCH3 - Si – OCH3, O2

OCH3

Work piece

13.5 MHz

H2O, CO2 ,

CH3OH

PUMP

Exhibit 6.3

PECVD coating process

Solution

Hydrolysis

Sol

Substrate

Xerogel Dense

coating

Substrate

Power supply

Work

piece

Air

Heat

exchanger

Pump

Acousto

hydrodynamic

generatorElectrolyte

Electrode 1 Electrode 2

Electrolyte

Plasma

discharge

Electrical pulses

Exhibit 6.4

Sol-gel coating process

Exhibit 6.5

Keronite (PEO) process

43


corrosion protection and adhesion propertiesand the economical and technologicalfeasibility of scaling up and using thesetechnologies via life-cycle assessments (LCAs).

The four candidate surface technologiesincluded in the study were:

• PAPVD• PECVD• Sol-gel• Keronite (PEO)

6.2.1 PAPVD

Plasma-assisted physical vapour deposition(PAPVD) coatings use thermal vaporisationand sputtering methods to build a coatinglayer on the substrate (see Exhibit 6.2).

Manipulation of the sputtering targetmaterial and sputtering power supplycontrols the deposition density andmorphology on the substrate.

6.2.2 PECVD

Chemical vapour deposition (CVD)techniques use liquid inorganic and organiccompounds and gases to deposit a coatingonto the substrate material or workpiece.

In the NANOMAG programme, the plasma-enhanced chemical vapour deposition(PECVD) process develops a silicon-oxidebased coating on the workpiece,generating a micro- and nano-structuredcoating (see Exhibit 6.3). The coating R&Dis being performed by the Universita degliStudi di Bari, supported with processoptimisation characterisation from theUniversity of Patras. Archer Technicoat Ltdof the UK are supporting with the provisionand design of the coating equipment.

6.2.3 Sol-gel

In principle, this coating uses ceramicsurface engineering technology. Sol-gelcoats the surface of a substrate with ahydrolysed ceramic liquid. After curing andfiring, the liquid becomes a very protectivesolid ceramic phase (see Exhibit 6.4).

This micro- and nano-coating technology andthe PAPVD technique were being researchedby CSEM SA (Switzerland).

6.2.4 Keronite (PEO)

As well as being the name of the company,Keronite is a registered trademark used todescribe a revolutionary new surfaceengineering technology designed for thetreatment of light metals such as alloys ofmagnesium and aluminium. It uses a uniqueelectro-ceramic method of surfacetreatment known as ‘plasma electrolyticoxidation’ (PEO).

Keronite technology uses an immersionprocess, whereby electrical pulses of bothpositive and negative polarities are passedthrough a bath of non-hazardous, chrome-free, low-concentrate alkaline electrolyte, asillustrated in Exhibit 6.5.

This treatment quickly transforms thesurface of the substrate metal into a hard,dense layer, providing protection fromcorrosion and wear.

A localised plasma discharge converts thesurface of light metal substrates into acomplex ceramic, by means of:

• Oxidation of the surface • Elementary co-deposition • Fusion of the ceramic layer

Keronite coatings perform well on a widerange of alloys, including some thatconventional anodising processes cannot

44


treat. Unlike most traditional coatingmethods, it is possible to interrupt thetreatment mid-process without damagingthe structure of the surface or the finish. It isalso possible to repair worn or damagedparts, restoring them to their originalspecification rather than discarding andreplacing them.

According to James A Curran, a researchscientist in the Composites and CoatingsGroup at The Gordon Laboratory,Department of Materials Science andMetallurgy: ‘Keronite coatings present anattractive combination of properties forapplications in the automotive andaerospace industries. The coatings exhibithardness and wear resistance that can besuperior even to plasma sprayed or EB-PVDcoatings and can significantly out-performanodised coatings in this respect. Moreover,the adhesion and low residual stresses inKeronite coatings could make them suitablefor high-temperature environments orthermal cycling.’

The four ‘new’ coatings – PAPVD, PECVD,sol-gel and Keronite – will be extensivelyassessed on demonstrator automotive andaerospace components within theNANOMAG programme.

The envisaged timescales at which thesefour coating technologies may be exploitedare also under detailed review.

6.3 Highlights

6.3.1 Industrial perspective

Most of the current applications using a lotof magnesium are automotive die-castings,and most are under-bonnet applications(engine covers and gearbox housings) andnon-visible body reinforcements (closureframes, front modules, seat frames, IP beams, headlamp brackets and, more recently, convertible roof frames).

Of the companies visited, BMW is themost advanced user of magnesium interms of tackling the practical corrosion andcoating issues. BMW presented a two-partpressed magnesium bonnet for whichKeronite is used as the anti-corrosioncoating. Also, the new magnesium engineis the talk of the automotive world, andeverybody we met in Germany expressedunprompted opinions about it. Even so, inthe most vulnerable area, it uses aluminium– a combined water jacket and cylinderhead – to resist corrosion and wear. BMWis interested in the possibility of large,stressed, magnesium castings.

Aerospace is being targeted for magnesiumnon-structural use (eg hostess trolleys, cabletrunking) only, due to corrosion andflammability risk. SZMT is particularlyinterested in aerospace because of thegreater margins available.

The supply of surface treatment isdominated by conversion processes ofHenkel and Chemetall. So-called nano-coatings, typically silane-based polymers, arealso seen as promising. Several organisationsworked with AHC’s Magoxid-coat, though noproduction applications were shown. Hellauses aluminised powder coat on magnesiumheadlamps, cast by HDO.

HDO specialises in casting small parts witha decorative finish. It has a partnership withAtotech, the US surface treatment company.Currently, the reject rate of headlamps is toohigh because of surface treatmentproblems. HDO also casts magnesium door‘grab’ handles for DaimlerChrysler, which arethen chrome plated. However, this is tooexpensive currently as it takes too manysteps, but further developments are takingplace to improve the cost and quality of thisdecorative finish.

MPI is the largest European supplier ofmagnesium parts. It has become an expert

45


in corrosion-resistant design (avoidance ofwater traps, multimaterial contact corrosion,etc). Some products, eg instrument panelbeams and seat frames, are sent to thecustomer with no coating of any kind.

For more difficult jobs – such as the ‘frontmodule’ – MPI has tested different pretreatments (chromate, Fe and Znphosphates, phosphor-permanganate,Alodine 5200, fluoro Zn, Keronite) and topcoats (primer e-coat and powder coat).Sometimes, MPI also uses coatings on seatframes to prevent squeaking of themagnesium against the seat padding.

6.3.2 Academic and RTO perspective

The distinction between universities andresearch and technology organisations(RTOs) visited is fuzzy. This image isreinforced by the many examples of cross-collaboration we saw, and by the existenceof the Fraunhofer Institutes often attached toa university. Broadly speaking, RTOs appearto be funded more heavily by governmentthan are the universities. The hosts mostactive in surface treatment of magnesiumwere GKSS and IFAM.

GKSS

The GKSS magnesium research centre hasa dedicated corrosion department, headedby Dr Wolfgang Dietzler. Its main

experience is studying corrosionmechanisms and providing testingservices. It has good test facilities, andexperience in stress corrosion cracking.One of the corrosion evaluation techniquesoffered at GKSS is the electrochemical pen(see Exhibit 6.6) for evaluating thecorrosion potential of a substrate and theinfluence of a coating or joining by meansof scanning the material, measuring thefree corrosion potential.

Such information could be used to improvethe joint processing to achieve improvedcorrosion performance, or in thedevelopment of coatings (see Exhibit 6.7),without the need for arduous corrosion salt-spray tests. This quantitative test methodprovides very detailed information on thecoating’s electrochemical behaviour, andinformation on any flaws or defects.

Exhibit 6.6

Electrochemical pen used at GKSS to determinecorrosion potential

Exhibit 6.7

Coating evaluation usingelectrochemical, scanning pen

46


GKSS has also performed investigations onthe corrosion behaviour of different joiningmethods of dissimilar metals, notablyaluminium and magnesium (see Exhibit 6.8).Again, GKSS works with partners indeveloping surface treatments.

GKSS’s plans are ambitious. Its vision is tofind coatings that are both wear- andcorrosion-resistant on magnesium.

It has two projects just starting:

• PVD – magneto sputtering, ion beam, arc evaporation, intermetallics, etc. This isbeing funded in the InnoMagTec initiative.

• A version of the PEO process is beingresearched, similar to that of Keronite,and is under co-development with aUkrainian research institute, at which itwas founded. They have already publisheda paper and want to study the influenceof different substrates and processparameters. Their targets are porosityreduction and identification of suitablesealants for better properties. So far, themorphology of this coating appearssatisfactory, though the properties are

currently not state-of-the-art. This projectis funded by GKSS.

Other target projects for the future includeinvestigations into plasma spraying, chrome-free chemical conversion coatings, followedby the development of polymer coatings.

IFAM

IFAM also displayed some excellent andmodern research facilities, and a professionalapproach. Significantly, it receives morefunding from industry than government.

IFAM, Bremen is the project manager ofMG-CHASSIS, one of the EU-funded MG-CLUSTER projects looking at the use ofmagnesium in the car industry. The goal isto reduce vehicle weight by the increaseduse of magnesium HPDC for automotivechassis components. The project aims tospecify materials for an engine support(with CRF), transmission mounts (VW) andan engine bracket (Opel). The workpackages include one on surface treatmentbeing carried out by the Swedish CorrosionInstitute in Stockholm.

Alloys were tested for corrosion resistanceamongst other properties, and a shortlistderived. These included AM60 (corrosionrate 3 mg/dm2/day), AZ91 (1.9) and threeMRI alloys (approx 0.6). The alloy choiceswere further corrosion-tested to see theinfluence of:

• Surface roughness: polished surfaceswere found to have approximately2x better resistance

• NaCl concentration: more NaCl gave more corrosion

• Temperature: ditto• Relative humidity: ditto• Presence of CO2 and SO2: more of each

reduced corrosion• Presence of other metals,

eg aluminium washers

Exhibit 6.8 Open circuit potential scan usingelectrochemical pen to assess freecorrosion potential of FSW of AZ31magnesium to AA5083 aluminium

X direction

AZ31magnesium

AA5083aluminium

Y d

irect

ion

Fre

e c

orr

osio

n p

ote

nti

al

(V)

47


So far, these tests have been carried out onbare magnesium only.

IFAM corrosion department is led by DrIhde who led a study to find the bestcorrosion protection coating process formagnesium components. He investigatedbought-in coatings Ti-F, V-Mn, a silane-basedcoating, an oxide-based coating (Magoxid-coat from AHC), plasma spraying and Cr6.On top of these, they applied variouspowder coats, e-coat, solvent paints and‘special coatings (MKS)’. The final preferredprocess was:

• Alkaline cleaning• Acid pickling• Cr6-free pretreatment• E-coat• Powder coat

A key conclusion was that a good-qualitymagnesium sample performs much betterthan a bad one, given exactly the samecleaning and coating.

The German system of research funding,especially Fraunhofer Institutes, seems tohave spun off a number of companiesdeveloping and selling so-called nano-coatings for magnesium and other materialswith good prospects.

6.3.3 Perceived technical/economic barriers

Cost is definitely seen as a barrier to thewider uptake of magnesium components inthe automotive industry, particularly the costof corrosion protection. In the aerospaceindustry, cost was not cited as an issue.Rather, risk of corrosion and flammability arefears that prevent magnesium use in primaryor even secondary structures.

In automotive applications, componentsmay be exposed to aggressiveenvironments that promote conditions of

accelerated corrosion. In applications inwhich components are exposed and/orvisible – such as door and tailgate frames,front-end structures, headlamp casings, etc– greater demands on the corrosionresistance and the aesthetic surface qualityof the component are placed. These newapplications are driving the demand forsuitable surface treatments for largemagnesium components.

For the majority of the assembled vehiclebody-in-white (BIW), a phosphate/electro-coat process will be used in conjunctionwith finish painting. Unlike steel parts,magnesium components cannot be directlyassembled to the vehicle. The reasons whythis is not practical are as follows:

• Standard phosphate treatments do notprovide adequate paint adhesion quality

• The phosphate tank environment which avehicle body and its closures passthrough is very acidic and causesdissolution of magnesium

• Fe ions will deposit on magnesium,dramatically reducing its corrosionresistance

Thus, for these applications, magnesiumrequires a pretreatment which is a chemical conversion of the material’ssurface. A pretreatment alone is not alwayssufficient to produce satisfactory galvaniccorrosion resistance.

6.3.4 Current and future research priorities

The largest funding for magnesium projectsin Europe is the EU MG-CLUSTER groupcomprising MG-CHASSIS, MG-ENGINE,MAGJOIN and NANOMAG, and collectivelythe funding is very significant. These allhave an automotive bias. UK representationis near zero. CRF has a coordinating role in all four and is also the project managerfor NANOMAG

48


NANOMAG is aimed at finding suitablesurface treatments for magnesiumcomponents, and is testing PVD, Keroniteand various polymeric nano-coatings. CRF reported that Keronite was the best coating tested.

Also of particular note is the newInnoMagTec initiative being coordinated byGKSS. It has assigned €3.5 million to 26 joint projects funded by the GermanResearch Council. The money will go toresearch centres and universities all overGermany. It has several projects dealing withcoatings for corrosion and wear resistance,including a PVD project at GKSS and two onmechanical treatment of magnesiumsurfaces, which could be interesting.

InnoMagTec has five working groups,including one focused on corrosion,illustrating that significant emphasis is beingplaced on corrosion protection.

For industry, automotive people we metwere trying to use alloy selection to offsetthe likelihood of corrosion rather than accepta surface treatment, in order to save cost.

6.4 Conclusions

• German organisations are very active inmagnesium research, and see it primarilyas a German metal.

• German industry benefits from significantfunding on magnesium research, spentunder a cohesive strategy, with manyorganisations working together.

• There is an EU-funded group of magnesiumprojects, MG-CLUSTER, from which UKcompanies are spectacularly absent. Insome cases, this money appears to begiven to novices who will gain significantground on their UK counterparts.

• Professor Kainer at GKSS is concernedabout the considerable activities ofChina, and believes EU funding isrequired if Europe is to preserve andprotect its magnesium industry. Such threats will also impact upon thesurface engineering industry, because if magnesium components aremanufactured in China, then they willalso be surface treated in China.

• Several organisations mentioned that theaircraft industry is a big potential marketfor magnesium. It is suited to low-volume,high-value manufacturing that still appearsto be sustainable in the UK. Addressingthe two main fears of flammability andcorrosion convincingly could differentiateUK industry. They do not appear to betackled well on mainland Europe, and wehave the expertise in the UK to make a breakthrough.

49


7.1 Introduction

In addition to the mission’s main aim ofbenchmarking UK magnesium technologyagainst European magnesium technology, itssecond role was to examine the use ofmagnesium in the European automotivesector and relate this to its use in the UKautomotive sector.

For an automotive part to be manufactured inmagnesium, the part must of course showbenefit with respect to the alternatives. Aswell as lightweighting, where magnesium hasa natural advantage over steel and aluminium,a magnesium design solution will haveadvantages and disadvantages with respect toalternative solutions manufactured from steel,aluminium or plastics. Obviously, the balanceof these is different for each part. Some of thekey aspects of an automotive productmentioned by the mission hosts included:

• Total cost• Crash impact behaviour• Part integration• Stiffness• Surface finish• Durability• Supply chain maturity and stability

One common factor which was highlightedon several occasions was that, in situationswhere magnesium was applied as a directmaterial substitution, little or no benefit wasgained. Applications where magnesium wassuccessfully applied tended to be situationswhere the part and/or system was specificallydesigned for magnesium.

Much is made of the driver for usingmagnesium for weight-saving. However, the

view of the European OEMs was that therewas little or no direct cost-benefit in weight-saving (except in specific parts such asremovable seats). Fiat stated that a costincrease of €2/kg weight saved was possible,but in practice weight-saving should be free.It should be considered that weight-saving isan order-winner for a cost-neutral alternative.

Thus, in order to assess the future ofmagnesium penetration into automotivemanufacture, it is necessary to consider notonly how the technology is developing, butalso what factors will affect the final part cost.

7.2 Magnesium supply and demand in

western Europe

7.2.1 Magnesium supply

The global production of magnesium hasbeen transformed over the last decade bypenetration into the western market ofmetal from the People’s Republic of China(PRC). In 1994, PRC magnesium accountedfor less than 20% of global production, withmuch of its production going into lowerquality applications such as desulphurisingsteel. By 2003, in spite of import tariffs inboth the EU and USA over some of thattimeframe, total market penetration hadincreased to ~65%, and to nearly 100% insome sectors such as desulphurisation.

Chinese penetration in the die-casting sectorhas been slower, with many companiestaking a conservative view regarding productquality and reliability. However, as theChinese producers have developed betterquality-control systems, sales haveincreased, and it is expected that thispattern will continue.

7 POTENTIAL FUTURE APPLICATIONS

AND TECHNO-ECONOMIC ISSUES

50


The effect of Chinese market penetrationhas also been felt by western producers,with over 250 kt of western productioncapacity being shut down or mothballedsince 19902. In addition to this, severalplanned western primary productiondevelopments have been abandoned. Thisfluidity in the supply market is of concern tothe OEMs as it poses the question ofwhether the supply chain is stable.

Unlike aluminium, magnesium is not a tradedcommodity. This means that no official pricedata are available. The price of western-produced magnesium softened from around$2,500/t through 2000, falling to $1,800-2,000/t by 2001. This coincides with the riseof availability of Chinese magnesium. Theprice remained roughly at these levels untilthe final quarter of 2003, when the pricerose sharply to $2,200-2,300/t, only to fallback to earlier levels by quarter 2, 2004. Thisprice spike was driven by Chinese prices andavailability, and was reported to have beencaused by raw material and power supplyissues in the PRC.

The price difference between western-produced metal and Chinese metal wasroughly $600/t in 2000. This has slowlyreduced as market confidence in Chinesemetal has increased; however, the situation

is complicated by changes to duty imposedby the EU and the USA. The current positionin western Europe (where there is no anti-dumping duty) is that there is now littlepremium for western-produced metal overChinese-produced, and that the prices (both western and Chinese) are driven bythe Chinese producer price.

7.2.2 Magnesium demand in western Europe

Utilisation of magnesium is dominated bythree applications: alloying with aluminium,desulphurising steel, and high-pressure die-castings. Other applications combinedmake up less than 10%. Aluminium alloyingand desulphurisation are not structuralapplications, so are outside the remit ofthis report.

Demand for magnesium in western Europehas shown an average of 10% growthacross all markets over the last 10 years,resulting in annual consumption rising from60,000 t in 1993 to 125,000 t in 2003. This rate of growth is roughly double that of North America over the same period.However, this growth is dominated by HPDCgrowth, which has been averaging over 20%throughout the decade (see Exhibit 7.1).

2 Robert L Edgar, The Magnesium Industry – Past, Present and Future, in: Proceedings of the 60th World Magnesium Conference, Stuttgart, May 2003, publishedby International Magnesium Association (IMA)

3 Source data: International Magnesium Association (IMA)

To

nn

es

50,000

45,000

40,000

35,000

30,000

25,000

20,000

15,000

10,000

5,000

0

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Exhibit 7.1

Western Europeanconsumption of magnesiumfor die-castings3

51


This growth is dominated by automotiveapplications, which make up the vastmajority of the die-castings produced, andcompares favourably with the situation inAmerica, where die-cast magnesium usehas reduced since 1999 (see Exhibit 7.2).

7.2.3 Magnesium demand in the UK

Magnesium die-casting production in the UKis currently less than 10% that of westernEurope, with 95% of the UK production (bytonnage) being concentrated in one producer.This is largely in line with the size anddemand of the UK’s automotive industry.

7.3 Wrought alloys

Currently, there are no European seriesproduction applications for the automotiveindustry that involve wrought magnesium.The economic factors affecting take-up ofmagnesium are very different for wroughtmagnesium (both sheet and extrusions). The growth in die-castings has led to aconcerted European research effort inwrought magnesium. For example, the FP5programmes MAGNEXTRUSCO andMAGJOIN, and the German government-funded programmes. From a commercialperspective, however, the prices of availablemagnesium extrusion and sheet are

significantly too high to interest the OEMs inseries production. VW quote that wroughtmagnesium has a current price range of€10-15/kg, with €5-8/kg as the target4.

There is an acknowledgment that thereason the wrought price is so high is acombination of technical and supplyfactors. The technical aspects, such asdifficulty in extruding and forming, are thefocus of much of the German researcheffort, whilst two large German companies– SZMT and Thyssen-Krupp – areaddressing the lack of magnesium sheetsupply availability. Both companies haveinvested heavily in the development ofsheet magnesium production capacity. Inthe UK, Magnesium Elektron hasdeveloped a magnesium sheet capacity byacquiring a rolling mill in North America.

7.4 Automotive applications

7.4.1 Powertrain

The powertrain is the part of the vehiclewith one of the largest potentials for weightreduction, and is also one of the greatest forpotential volume magnesium applications.

In 2004 BMW launched a ‘composite block’consisting of an inner casting made from

4 S Schumann & H Friedrich, The Route from the Potential of Magnesium to Increased Application in Cars, in: Proceedings of the 60th World MagnesiumConference, Stuttgart, May 2003, published by IMA

To

nn

es

100,000

80,000

60,000

40,000

20,000

0

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Exhibit 7.2

North and South Americanconsumption of magnesiumfor die-castings3

aluminium, which contains the cylinder linersand the coolant, surrounded by a magnesiumalloy HPDC crankcase. This component is forthe new straight-6 series of engines and willbe in high-volume series production in 2005.

VW have been investigating similartechnology, and in 2004 showed research ona 4-cylinder block.

VW/Audi introduced manual magnesiumgearboxes on some Passat and Golf modelsin 1996.

In 2003/4 Mercedes-Benz introduced anautomatic magnesium gearbox ‘7-speed tip-tronic’, shown in Exhibit 7.3.

7.4.2 Structural castings

Magnesium is being widely used for IPbeams. These parts integrate a structuralcross-member running behind the dashboardwith various attachments for functions suchas dashboard or centre consoles.

7.4.3 Other castings

Magnesium is now widely used for manynon-structural or secondary structural castingsin high-volume series. Notable examples aresteering wheels and steering columnsupport/lock housings, where there has beena high level of conversion to magnesium.

These applications are seen as traditionalmagnesium applications (see Exhibit 7.4).

Of particular interest is the use of magnesiumfor interior trim parts, whereby magnesiumprovides a metallic look and feel that iscurrently sought after over other substratematerials such as injection or blow mouldedengineering plastics, at no weight penalty.

In luxury and performance cars, magnesiumcastings are also being used for seats (see Exhibit 7.5), door inners and convertibleroof supports.

In a low-emissions version of the Lupo, VWproduced a magnesium die-cast hatchbackinner (see Exhibit 7.6). Such projects enablethe OEM to develop technologies in orderthat they may be shelf-engineered, so thatat a later date they can be called upon withknown or defined solutions.

7.4.4 Wrought applications

There are no current applications of wroughtmagnesium known to be in seriesproduction. However, there is considerableinterest and development/demonstrator worktaking place in the European automotiveindustry, much of which is highly confidential.

7.4.5 Beyond automotive applications

Whilst automotive applications are likely toremain the dominant consumer ofmagnesium alloys, growth is also envisagedin their uptake by fielding them in applicationsin the following sectors or industries:

• Aerospace • Rail• Military• Information and communications

technologies • Power generation• Leisure • Medical

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Exhibit 7.3 Mercedes-Benz 7G-Tronic – seven-speedautomatic transmission

53


Exhibit 7.4 Traditional HPDC magnesium componentapplications

Exhibit 7.5

HPDC magnesiumseat frame

Exhibit 7.6 Magnesium die-cast tailgate innercomponent and mission team at GKSS

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Each market sector is likely to have its ownR&D activities in order to meet its specificrequirements. This in itself is also a majorbenefit, as this activity will also increase andassist the knowledge and research base formagnesium alloy product forms.

7.5 Conclusions

• Magnesium deployment in automotiveapplications is showing strong growth inEurope. Its use as high-pressure die-castings has recently been extended toinclude blocks, gearboxes and structuralmembers. As these applications aresuccessful on their specific platforms,they will stimulate further expansions andtransfer to other platforms and sectors.

• Wrought magnesium is less welldeveloped, and needs considerableprocess development and cost reductionbefore automotive applications in seriesproduction will be viable on anythingexcept the most expensive platforms orvery-low-volume luxury or performancemodels. Significant potential also exists forwrought magnesium in other industriesthat are not sensitive to its price.

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8 R&D FUNDING AND

INFRASTRUCTURE

A notable feature of the mission was to gaina better understanding of the level ofcollaborative research involving magnesiumsince the late 1990s.

The German government has been funding a significantly high level of magnesiumresearch. InnoMagTec1 – funded by theGerman Research Council – aims atextending the applications of magnesiumalloys. The project comprises 107 researchproposals, and has been allocated a budgetof €19.4 million. GKSS are involved in thisprogramme, along with Hamburg,Paderborn, Dortmund, Aachen, Erlangen,Karlsruhe, Freiburg, and Ranshofen inAustria. Initial results will be presented after18 months.

The German Federal Ministry of Educationand Research (BMBF) has been fundingcollaborative magnesium research withIsrael under the MINERVA project, believed to be of value around €4 million.Magnesium sheet also features in theBMBF-funded super-light-car project (Ultra Light parts in Magnesium – ULM),with the target of developing a 1-litre VWcar having total weight of 260 kg, witharound 35 kg of magnesium.

8.1 EU research projects

A non-exhaustive summary list of EU-fundedmagnesium research projects since 1998 isgiven in Exhibit 8.1. These projects cover thewhole range of areas important to industry,from alloy development to manufacture,finishing and joining. It is estimated that thetotal value of this research is of the order of€37 million, of which around 50% has beenprovided by the EU. Of the 24 projects

listed, only 7 involved UK participation, and the majority of those were FP4 projectsengaging small UK organisations.

A significant activity relates to a number ofmajor FP5 magnesium research projects inprogress: MG-CHASSIS; MG-ENGINE,NANOMAG, MAGJOIN. These projects havebeen clustered to form MG-CLUSTER, tofacilitate the synergy achievable by transferringknow-how from one project to another.

A brief summary will now be given of thekey research projects in this cluster.

MG-CLUSTERCoordinator: CRF (Italy)

This cluster has been organised to promotea synergic effect from multiple results of thedifferent projects and to integrate thenecessary large quantity of activities in aneffective way, such that it will be possible toembrace almost all kinds of application inthe field of the automotive industry.

MG-CHASSISCoordinator: IFAM (Germany)

The objective of the project is to develop amanufacturing technology for the productionof lightweight magnesium chassiscomponents for high-toughness applications(eg wheels, chassis), and to validate this fortwo demonstrators. New magnesium alloyswith improved mechanical properties andbetter corrosion resistance will be used, andimproved joining techniques. A fatigue-lifeestimation method and quality-assurancemethods for highly loaded parts willcontribute to the design guidelines formagnesium components.

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Project title Completion EU funding UKdate (€)

FP4 projects

Design and processing of selectively reinforced Mg-based components 1998 Y

Shaping of magnesium and aluminium alloys by pressure die-casting 1998 Nin the semi-solid state

MAGDOOR: magnesium door inner 1999 N

Thixoforming of advanced light metals for automotive components 1999 N

Action for low-weight automotive technologies 2000 Y

Calculation and experimental investigation of the phase diagrams Mg-Li-X 2000 N

Development and testing of new surface treatment processes for 2000 Nmagnesium alloys

SAMMI: safe and economic machining of magnesium castings 2001 N

Autopassive wrought magnesium alloys 2001 Y

CREEPAL: long-term creep and thermal-mechanical cycling behaviour 2001 Yof aluminium alloys

FP5 projects*

Development of novel materials in mechanical engineering 2002 22,006 N

Ecological and effective high-speed machining of magnesium 2002 650,000 N

MAGJOIN: new joining techniques for light magnesium components 2003 1,578,739 Y

MAGNEXTRUSCO: hydrostatic extrusion process for efficient production 2004 1,447,145 Nof magnesium structural components

MAGCAST: production line integrated sensor system for porosity quality 2004 975,800 Ycontrol of magnesium die-castings

REMACAF: recycling of magnesium chips and flash/fines 2004 500,469 N

SEPCAST: sustainable and economic production of 2004 2,306,033 Nmagnesium components

MG-CHASSIS: advanced manufacturing technology for automotive 2005 2,648,965 Nchassis components through extensible and sustainable use of Mg alloys

NANOMAG: development of innovative nanocomposite coatings 2005 3,386,475 Yfor magnesium castings

EUROMAGUPCASTER: European magnesium upward continuous caster 2005 1,705,509 N

MAGBODY: magnesium-intensive, multimaterial body structures by advanced joining technologies 2005 117,600 N

MG-ENGINE: lightweight engine construction through extended and sustainable use of Mg-alloys 2005 1,849,395 N

RHEOLIGHT: rheocasting – an innovative and ecological process for light and cost-effective applications in different industrial sectors 2005 1,275,351 N

FP6 projects

MAGFORGE 2007 N

* EU FP5: Total EU funding around €15.8 million, ie total project value around €31.6 million (~£22.5 million); UK involvement – 3 from 13 projects

Exhibit 8.1 EU-funded R&D projects for structural magnesium

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Fuel consumption and CO2 emission ofpassenger vehicles are associated with agrowing demand for low-weightcomponents. As a consequence,magnesium has recently gained importancedue to its low density and the high strength-to-weight ratio. However, existingmagnesium alloys are not suitable for thickcomponents requiring high strength andductility. Furthermore, the currentmanufacturing technology has to bemodified in order to fulfil the requirementsof high-volume production. The overallobjective proposal is therefore to develop asuitable manufacturing technology for theproduction of lightweight magnesiumchassis components and to validate this fortwo demonstrators.

IFAM is investigating HPDC, warm chamber(700 t) and cold chamber (4,500 t); and usinga large X-ray facility to inspect quality.

The total funding for MG-CHASSIS is worthsome €5.1 million total, and the EUachieved a 50% funding level. The partnersfor this programme include IFAM, CRF,DaimlerChrysler, Opel, Stockholm CorrosionInstitute, Dead Sea Magnesium Ltd, andCBF Darmstadt.

Key elements of research include:

• Alloy development/evaluation• Process study and selection (looking at

sand casting + liquid HIPing (at CRF) toreduce porosity

• Corrosion and surface treatmentevaluation (VICT)

• Exploitation (data compiled and disseminated)

Demonstrator components to be evaluated:

• VW transmission housing (squeeze cast)• Opel engine bracket (HPDC)• Engine support (CRF)

MG-ENGINECoordinator: Riso (Denmark)

The objective of the project is to developnew magnesium alloys with improved high-temperature properties, to develop ageneric engine-block design, and tomanufacture engine-block prototypes. It willtake into consideration traditional castingprocesses, but material will be improved bymodification of existing magnesium alloysto increase the mechanical properties athigh temperature. Gluing and fasteningtechniques for high temperature arefundamental topics, which will be examinedin synergy with project MAGJOIN.

The total cost of the MG-ENGINE project is€4.1 million. The partners are: Volvo (Sweden),Renault (France), Norsk Hydro (Norway),Noranda (Canada), Honsel (Germany), CRF(Italy), DaimlerChrysler (Germany), BMW(Germany), Adam Opel (Germany).

NANOMAGCoordinator: CRF (Italy)

The objective of the project is to developnew corrosion and abrasion resistantcoatings for the protection of magnesiumparts, by using clean, environmentallyfriendly and economic processes.

MAGJOINCoordinator: CRF (Italy)

This project was completed in 2003 at acost of €3 million, and established a state-of-the-art for processes and metallurgy formixed joints. A suitable configuration ofweldable joint by laser and arc processeswas described, and some specific jointswere selected for further experimentation.Study and definition of metallurgical effecton weldability of mixed joints wascompleted, and a list of filler materialspossible for mixed joints was collected. Filler materials of different chemical

58


composition were produced and transformedinto powder useful for laser weldingapplication. Filler materials in powder-coredwire shape were also produced for laser andarc welding of mixed joints.

A complete and equipped laser-welding tool-head has been designed (on the basis ofprecise specifications) and built forexperimental test. Integration of weldingtool-heads in two different places (CRF-Italyand DLR-Germany) was made, and testvalidation carried out with positive response.

Weldability test for mixed joints Mg-Mg andAl-Mg was carried out by CO2 and Nd-YAGlaser with positive response. Friction stirwelding (FSW) has also been tested formixed joints, and weldability was established.

The project has been focused mainly on thebasic research concerning joining ofmagnesium cast alloys with magnesium andaluminium alloys. The aim has been todevelop joining technologies (welding andadhesive bonding), and related feedingmaterial and equipment, for mixed joints tobe used in the above-mentioned projects(and also in other industrial sectors) forcomponent development and manufacturing.

MAGNEXTRUSCOCoordinator: Audi AG (Germany)

The project aims to develop a new processfor the production of lightweight, cost-effective and safe magnesium structures,based on the hydrostatic extrusion principle.

One section of the MAGNEXTRUSCOproject focuses on the development of anefficient process for magnesium extrusion,including development of improved alloysand billets as well as the study of processingtechniques. The expertise on joining ofmagnesium structural parts will be obtainedfrom the recently started MAGJOIN project.The exchange of know-how is secured,

as the coordinator of the MAGJOIN projectalso participates in this project. The othersection of the MAGNEXTRUSCO projectfocuses on the design and development oflightweight magnesium structures fortransport purposes.

The most interactive parts of the project arethe alloy and billet preparation development,the study of the processing techniques, andthe structural integrity assessment, whichwill provide feedback for further research.This approach has been chosen to securethe most optimal outcome of the project, asit considers the whole chain from materialproduction and processing to end-use.

Total project funding is €2.5 million, with theEC’s contribution being provided under theGROWTH programme. Coordinated by AudiAG, the consortium comprises nine partners,including IBF, GKSS, Boliden, Rond, UUKV,IRF and TNO.

8.2 Additional projects

Following is a list of some of the mainprojects involving the mission hosts:

LKR

• MMC pistons (ALICE)• Co-extrusion of magnesium core with

aluminium outer layer (cooperation with EADS)

• Round-robin on recycling of magnesium(Noranda Tech Centre, BMW, Magnola)

• Major lightweighting project starting in 2005

IW, University of Hannover

• EU project EUROMAGUPCASTER todevelop a continuous casting techniquefor magnesium, and numerical simulation model

• Ultralight parts in magnesium sheet –BMBF-funded project ULM

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• Project ‘Innovative Mg structures for carbodies’ (InMaK) – castings and extrusions,welded. Partners: EADS, Honsel, Ford,IW, Elisental, Lazer Zentrum Hannover

Meridian

• MAGDOOR• New development with Norsk Hydro –

engine oil-pan in anti-creep alloy• Crash research – MEPROMA. Partners:

Renault, Volvo, Norsk, VW

GKSS

Many international project collaborations:

• EU project MAGNEXTRUSCO: €2.5 million. Partners: Audi, IBF, TNO,GKSS, Boliden, Rond, UUKV, IRF.Hydrostatic extrusion

• EU project MAGFORGE. Partners includeTNO, GKSS, IMA, TU Hamburg, MonashUniversity (Australia)

• Joining: European ‘Fitness for Service’Network (FITNET) (thematic network)

• WEL-AIR – EU project on laser beamwelding – looking at T-joint skin-stringer

• EU project ‘Mag for Aero’ run by Airbus Ottobrunn

IFAM

• MG-CHASSIS: €5.1 million. Partners:IFAM, CRF, Speedline (withdrew), VW,Opel, DaimlerChrysler, ChalmersUniversity, Dead Sea Magnesium, CBFDarmstadt, Volvo. Ends January 2005 –requesting extension

• MG-ENGINE• MAGJOIN• MG-CLUSTER for above three projects

(Riso, IFAM, CRF)

CRF

• 1996 MAGDOOR – magnesium door frame

• 2000 MAGJOIN – Joining magnesiumchassis components

• 2001 MAGNEXTRUSCO – magnesiumextrusion process

• 2001 MG-CHASSIS – magnesium engine support

• 2002 MG-ENGINE – magnesium engine block

• 2002 NANOMAG – corrosion protection –affordable, sustainable

Networks

• Network – industrial community forpromotion of light metal research (RWTHinvolved)

• FITNET – EU ‘Fitness for Service’thematic network (GKSS involved)

8.3 Summary and recommendations

• It is clear that a significant level ofcollaborative and government-fundedresearch has been undertaken in Europeover the past five years, in which the UKhas had next-to-zero involvement. Thisdegree of involvement in EU-fundedprogrammes is a reflection of thetemporary state of the UK automotiveindustry, in terms of financial climate butalso a reflection of the UK in general.

• It is also felt that the UK position onmagnesium R&D is unlikely to achievelevels mirroring Germany without asignificant up-turn or investment fromcompanies such as Jaguar, Land Roverand Aston Martin or by Japanesemanufacturers. It is also believed that thescale of activity does not always bearfruit, which has been observed by someof the R&D programmes in Europe. It istherefore recommended that the UKshould direct its research efforts andfunding strategically in order to achievethe greatest gains.

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• It is envisaged that by raising the profileof magnesium, greater levels of up-takewill be seen, especially under pressuresto continuously reduce harmful emissionsproduced by transport. Greater levels ofparticipation in collaborative R&D will alsofollow interest in what potentialmagnesium alloys and technologies haveto offer.

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9 INDUSTRY PERCEPTIONS AND

TRAINING AND EDUCATION

Beyond technological barriers, which arebeing addressed by R&D activities inEurope, nothing is being done to tackle theembedded industry perceptions, particularlyrelating to the corrosion and flammability ofmagnesium. Misperceptions can cause agreater degree of harm to the growth andspread of magnesium alloys and relatedtechnologies than mere technological ones.Preclusion based upon misinformation hasaffected the motor industry, but this is notthe same situation in Germany, with end-users and suppliers working closely ondevelopments in magnesium.

In terms of training and education,Germany has had no particular trainingfocus or activities that were raisingmagnesium’s profile, and the only means ofdoing so was through the publication ofresearch information via the usual channels.As much of the applied research was beingdriven by the end-user, namely vehiclemanufacturers such as VW AG, Audi AG,BMW Group, DaimlerChrysler and theirsuppliers, training and education does notappear to be an issue for Germany’sautomotive sector.

CRF’s role on conducting many of the largeEU applied R&D programmes intomagnesium has given them great access tosome of the leading magnesium research inEurope, and indeed on an internationalscale. Due to Fiat’s links with MeridianTechnologies Inc, via MPI, Fiat group hasbeen at the forefront of many newdevelopments and applications of HPDCmagnesium, some of which involvedexploring completely unchartered territory.

On the whole, the benefits of usingmagnesium are relatively well understood inautomotive circles. This knowledge andacceptance is not mirrored by the rail oraerospace sectors, that look on magnesiumwith a great deal of scepticism. During themission, a representative of SZMT madereference to the fact that when they haveheld discussions with members of the railindustry, the rail industry has mocked themwith statements like, ‘magnesium isflammable’ and therefore is not suitable forrail applications. More success has beenmet with proactive aerospace organisationssuch as EADS.

This appears, therefore, to be a majoropportunity for the UK. Through appropriatetraining and education programmes, greaterawareness of the potential for magnesiumcan be achieved to the benefit of the UK.This may be a key focus for a UK network,amongst others.

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10 GENERAL CONCLUSIONS

10.1 Research

The mission to Europe confirmed that therehas been a considerable level of researchactivity into magnesium, their alloys, newtechnologies and applications, especiallyautomotive applications.

Research has also been conducted at alllevels, from microstructure and texturecontrol to mechanical performance andcomponent process developments.

In particular, Germany was found to be thecentre of a hub for considerable researcheffort into magnesium component andapplication development which incorporateda network of some 28 institutes oruniversities researching magnesium. Thisresearch network is also strongly allied toother European organisations through EUresearch, and via VW’s links to Dead SeaMagnesium Ltd in Israel, and via GKSS andits links with LKR in Austria. This level offocus on magnesium puts Germany as theworld leader in terms of magnesium alloyand process R&D. CRF were also found tobe at the heart of many developments.

Interestingly, the significant levels of appliedresearch in Germany, such as thedevelopment of materials processtechnologies, were very well balanced byfundamental research into alloy and texturedevelopment. Another, key aspect that wasnoted was that the Fraunhofer Institutes hadbegun to work in close collaboration withthe universities to access corecompetencies in more pure or fundamentalresearch, and therefore offer a morerounded research package to industry.

10.2 Industry misconceptions

Misconceptions within the automotive, railand aerospace industries are still rife, andcould be tackled in a manner so as toalleviate some of these understandable butrather primitive fears.

Comments such as ‘Is magnesium thatmetal that ignites when exposed to air?’ are all too familiar to magnesium component and materials suppliers.

Although very far from the truth, suchmisconceptions are very damaging, andappear to hamper the increase in usage ofmagnesium within the automotive and otherindustries such as aerospace and rail. We allremember the science classes at schoolwhere a magnesium strip was ignited andimpressed everyone with its bright light andintense heat. The truth of the matter is thatmagnesium has one of the best heat-dissipation qualities of all natural metals, andis very difficult indeed to ignite. It has passedall the ignition tests within the automotiveand aircraft industries, without issue.

Provided there is sufficient information in thepublic domain for people to make informeddecisions, these misconceptions could beeradicated, resulting in a thriving magnesiumindustry that could provide many solutions toour future transport needs. It is intended thata programme be formulated to address theserather obvious education and training needs.

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11 KEY FINDINGS

Casting technologies

Rheocasting processes show significantlygreater potential to reach market for theproduction of structural castings thanthixocasting and thixomouldingtechnologies, largely due to cost-relatedfactors. Pilot-scale trials remain necessaryto achieve implementation readiness forseries production. Two Europeantechnologies show significant promise,namely the new rheocasting (NRC) andrheo-diecasting (RDC) processes.

Casting alloy development

Significant efforts in this field of magnesiumresearch have enabled a new generation ofhigh-performance powertrain and drivetraincomponents to be produced, and will fuelfurther developments.

Wrought magnesium technology

The research to date demonstrates thatmagnesium components can readily beproduced. However, the cost of wroughtmagnesium remains the greatest barrier touptake. For sheet material, this is not likelyto change rapidly, despite technologydevelopments and the introduction of innovations.

Joining technologies and integration

This remains an exciting area, asdevelopments are essential to enable largestructures or assemblies to be produced,and next to material price, will govern muchof the total piece cost.

Surface treatments

A series of new coatings for magnesium is on the horizon, each with uniqueproperties. Considerable effort is stillrequired to improve scale-up of thesetechnologies, at which point the economicsof using these techniques will becomemore desirable. Like joining technologies,these may become fundamental enablingtechnologies for magnesium and its futuregrowth and diversification.

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12 RECOMMENDATIONS AND

FOLLOW-UP ACTIONS

How might the UK accelerate thedevelopment and deployment of magnesiumtechnology, and reduce the technology gapbetween the UK and its international rivals –or at least prevent it from growing? These arekey issues, and – arising from the mission –there are two key recommendations targetedat addressing them:

1 Create a network to strengthen thecompetitiveness of the UK magnesiumsupply base and related industries andorganisations. It is envisaged that this willbe an association of UK companies andknowledge institutes that would:

• Share needs and competencies toassist both the development anddeployment of magnesium alloys andtechnologies for components,structures and systems

• Provide a mechanism to train andeducate the UK’s industry, particularlynon-users

• Tackle potential legislative or regulatorymeasures or barriers

• Improve and create better internationallinkages, including the hostorganisations visited during this mission

2 Conduct more basic and applied researchin the UK, into the development of:

• New magnesium casting alloys and technologies

• New and improved magnesium joining technologies

• Wrought magnesium alloys andproduct technologies

• Magnesium coating technologies

Significant effort has been made to ensurethat this information is disseminated toother potential industry sectors, which mayultimately improve the opportunity formagnesium alloys to be recognised assuitable materials for lightweight design. It is aimed that this will continue.

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ARC Leichtmetallkompetenzzentrum

Ranshofen GmbH (LKR)

www.lkr.at

LamprechtshausenerstraßePostfach 265282 RanshofenAUSTRIA

Dr-Ing H KaufmanDirectorT +43 7722 83333 – 7007F +43 7722 83333 – 2

Dipl-Ing Rudolf GradingerHead of Lightweight DesignT +43 7722 83333 – 7007F +43 7722 83333 – [email protected]

LKR – Light Metal Competence Centre,Ranshofen – has 40 employees focused onR&D in light metals, particularly Al and Mg.LKR, a 100% subsidiary of the AustrianResearch Centres (ARC), provides contractconsultancy and R&D for industry, and has aturnover of ~€5 million. Its three key areasof competence are materials, processingtechnologies, and manufacturing. LKRemerged from the former researchdepartment of Austria Metall AG (AMAG),the leading national aluminium-processingcompany, and is therefore proficient inworking on light metals.

BMW Group

www.bmwgroup.com

FIZ – Research & Innovation CentreMunich GERMANY

Dr-Ing A Istrate InnovationsingenieurT +49 89 382 39123F +49 89 382 [email protected]

Some 5,000 researchers, engineers andtechnicians work at the FIZ, although BMWGroup employs over 105,000 people invarious countries globally.

BMW Group is the only global manufacturerof automobiles and motorcycles thatconcentrates entirely on premium standardsand outstanding quality for all its brands andacross all relevant segments. BMWrecognises the need for R&D, which isdemonstrated through its products. Theemphasis on R&D is also demonstrated bythis company’s R&D spend, which has beenabove €2 million for the last two consecutiveyears, slightly above 10% of profit.

Appendix AHOST ORGANISATION PROFILES

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Foundry Institute – RWTH-Aachen

www.gi.rwth-aachen.de

Gießerei-InstitutIntzestraße 5D-52072 AachenGERMANY

Prof Dr-Ing Andreas Buehrig-Polaczek

Dr-Ing Martin Fehlbier Chief EngineerT +49 241 80 95241F +49 241 [email protected]

Aachen University has ~29,000 students,including 6,500 foreign students from 100countries, and has 260 departments andinstitutes. Much of the focus of the FoundryInstitute is on die-casting, investmentcasting, numerical simulation techniques,and alloy and material developments. Theinstitute has 58 scientists, 31 technicians,and 80 student workers who contribute toinstitute activities as part of their course.

GKSS Research Centre

www.gkss.de

Institute for Materials ResearchCentre for Magnesium TechnologyMax-Planck-StrD-21502 GeesthachtGERMANY

Prof Dr Karl Ulrich Kainer Head, Centre for Magnesium TechnologyT +49 4152 872 590F +49 4152 872 [email protected]

GKSS is a large research centre with anannual budget of €75 million, of which €58 million is provided directly by theGerman government, €16 million by public-funded (EU) projects and €1.8 millionby industry. GKSS employs 750 staff.

The Centre for Magnesium Technology isheaded by Professor Karl Kainer, a centralfigure in the magnesium world, who alsocoordinates the InnoMagTec programme.The Centre has 36 staff, including 10 PhDs,and an annual budget of €1.9 million, ofwhich 25% is from third-party funding. Core areas of research include:

• Development of new cast and wrought alloys

• Optimisation of known and newlydeveloped processing routes forcommercial and new alloys

• Microstructure, properties and modelling• Introduction of magnesium in combination

with other materials

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Salzgitter AG

(Meeting at GKSS. Co-host with GKSS)www.salzgitter-ag.dewww.szmt.de

Salzgitter Magnesium-Technologie GmbH(SZMT)Eisenhüttenstraße 9938239 SalzgitterGERMANY

Dr Peter JuchmannManaging DirectorT +49 5341 21 39 57F +49 160 47 12 [email protected]

As a young subsidiary of Salzgitter AG,Salzgitter Magnesium-Technologie GmbH(SZMT) is dealing with the development,production, application and sales of high-quality magnesium flat-rolled products. The company offers an efficient technologyand material partnership for productdevelopment and series applications.

IFAM

www.ifam.fhg.de

Fraunhofer-Institut für Fertigungstechnik undAngewandte Materialforschung Wiener Straße 12D-28359 BremenGERMANY

Mr Franz-Josef WoestmannHead of Department Casting Technology T +49 421 2246 225F +49 421 2246 77 225 [email protected]

Fraunhofer IFAM offers R&D services,optimisation of casting processes, and technology transfer in the followingareas of technology:

• HPDC (hot and cold chamber)• Thixocasting• Squeeze casting

IFAM has recently installed new die-castingequipment and is looking to engage in newcollaborative R&D programmes.

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Meridian Magnesium Products of Italy srl

(MPI)

www.meridian-mag.com/FacilityNav.html?MPI

Via Glair 4111029 Verres ITALY

Marco ParmaPlant and Business Unit ManagerT +39 0125 922 301 F +39 0125 922 211 [email protected]

The MPI plant started production of die-casting in 1996, and today has ~250 employees working within this modern 135,000 ft2 facility. The impressiveMPI plant boasts 13 die-casting cells:

• 1 x 420 ton • 1 x 900 ton • 4 x 1,500 ton • 7 x 2,500 ton

At MPI, magnesium components such asIPs, cross-car beams, seat frames andsteering column brackets are produced forthe automotive industry using HPDCtechnology. Key customers include FiatAuto, Jaguar, BMW, DaimlerChrysler, Lear and Opel.

Centro Ricerche Fiat (CRF)

(Co-host with Meridian MPI)www.crf.it

Strada Torino 5010043 Orbassano (TO)ITALY

Silvio CorriasHead of Materials Engineering DepartmentAdvanced Process TechnologiesT +39 011 9083 354 F +39 011 9083 666 [email protected]

CRF was founded in 1976 as an engineeringcentre providing R&D services to each ofthe different companies within the FiatGroup. Today, although the links to Fiat Auto,Iveco, CNH and other Fiat-ownedorganisations remain as strong as ever, Fiat now places greater emphasis oncollaborative business-to-business research.CRF works with an extremely wide range oforganisations, including those belonging toother sectors, such as railway, marine,aerospace, space and military.

CRF has some 930 employees includingboth researchers and other staff. CRF alsoboasts an annual turnover of €120 millionand develops more than 450 products andtechniques annually. To date, CRF hasdeveloped over 1,150 patents and awaitsthe approval of a further 850.

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Appendix BMISSION TEAM DETAILS

The mission team comprised nine delegates from the UK, listed in Exhibit B.1. Further details are given on the following pages.

Original AZ31- AZ31 AZ31 AZ31Name Organisation Location Representing

Dr Tim Wilks Magnesium Elektron Manchester Materials supplier

Mr Steve Brown Meridian Technologies Sutton-in-Ashfield Tier 1/2 supplier (die-castings)

Dr Steve Hutchins Keronite Cambridge Coatings technology supplier

Mr Rob Butler Superform Aluminium Worcester Tier 1/2 supplier (SPF pressings)

Prof Z Fan BCAST (Brunel University) Uxbridge Academia

Dr Geoff Scamans Innoval Technology Banbury Technology consultancy

Dr Roger Darlington Faraday Advance Nuneaton/Oxford Mission coordinator

Dr Martin Kemp DTI Global Watch Service Melton Mowbray Government agency

Mr Frank Rott DTI Global Watch Service London Government agency

Exhibit B.1 Mission team overview

Exhibit B.2 Mission team at Meridian MPI, Verres, Italy

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Dr Tim Wilks

Technical Manager (UK)

Magnesium Elektron Ltd (MEL)

PO Box 23SwintonManchesterM27 8DDUKwww.magnesium-elektron.com

Magnesium Elektron, a division of LuxferGroup, is a dedicated service organisationspecialising in the development,manufacture and supply of magnesiumproducts and services to technologyindustries worldwide.

Since the company first began processingmagnesium in 1936, its team has built anenviable reputation for innovation, built upona relentless passion to push themetallurgical boundaries of magnesium alloytechnology. The aim is to build lastingrelationships with its clients by working withthem, as a partner of choice, to achieve theiroperational objectives.

The company is based in Manchester, UK,but has satellite plants in North America andEurope. It employs 640 people worldwide,with 186 in Manchester.

Mr Steve Brown

Business Development Manager

Meridian Technologies Inc (UK)

Orchard WayCalladine Business ParkSutton-in-AshfieldNottinghamshireNG17 1JUUKwww.meridian-mag.com

Full service design and manufacture ofmagnesium high-pressure die-castings.These castings can be structural or non-structural. Meridian presently supplies 100%of its services to the automotive industry.

Meridian Technologies (UK) –

• Employees: 30• Annual turnover: ~£15 million • Machine size: 3,200 t (largest European

magnesium casting machine)

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Dr Stephen Hutchins

Commercial Director

Keronite Ltd

Granta ParkGreat AbingtonCambridgeCB1 6GPUKwww.keronite.com

Keronite Ltd was incorporated as a limitedcompany in March 2000 to commercialisethe Keronite surface treatment technology –a unique plasma electrolytic oxidation (PEO)process for light metal alloys.

In addition to its own in-house productionfacilities for short-run or highly specialisedjobs, Keronite Ltd sells licences to coatingscompanies and to OEMs wishing to use thetechnology for volume production. It not onlyprovides the know-how to its licensees, butalso manufactures and supplies thenecessary machinery and associatedchemicals. The company has sold licencesand installed processing equipment inEurope, North America and Asia.

Today the company has two wholly-ownedsubsidiaries: Isle Coat Ltd and ICSSystems. Isle Coat owns the IP relating tothe unique Keronite process. ICS Systemsnot only supplies the processing equipmentfor the production of Keronite coatings butalso offers metal finishing equipmentsystem design services, as well as a widerange of standard and custom-builtrectifiers, heating systems, plating barrelsand other accessories.

Keronite Ltd has 18 employees and anannual turnover of £2.2 million.

Mr Rob Butler

Development Manager

Superform Aluminium

Cosgrove CloseBlackpoleWorcesterWR3 8UAUKwww.superform-aluminium.com

Manufacturer of superplastically formedsheet aluminium components. Productsinclude automotive panels, aerospacedetails, rail carriage structures, and bodyscanner ends. To date, these products havebeen largely made in aluminium alloys.

Originally, Superform Aluminium was aTI/British Aluminium Company which becamepart of British ALCAN, and is now whollyowned by Luxfer Group. The company ismirrored by Superform USA – California.

Superform Aluminium has 85 employeesand an annual turnover of ~€10 million.

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Professor Zhongyun Fan

Director

BCAST (Brunel Centre for Advanced

Solidification Technology)

Brunel University

UxbridgeMiddlesexUB8 3PHUKwww.brunel.ac.uk/research/bcast

Brunel University has 15,000 staff andstudents, and has an annual turnover of£22.2 million.

BCAST is an academic research centrefocusing on both theoretical and technologicalresearch on solidification. It has 18 researchstaff, the majority of whom are working onresearch projects related to magnesium.

Dr Geoff Scamans

Principal Scientist

Innoval Technology Ltd

Beaumont CloseBanburyOxfordshireOX16 1TQUKwww.innovaltec.com

Innoval Technology Ltd is a materialsconsultancy that specialises in light metalproduction and utilisation in automotive,architectural and packaging applications.

Formed in 2003, the company presently has29 employees and an annual turnover of£2.7 million (2003).

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Dr Roger Darlington

(Mission Coordinator)

Faraday Advance

Begbroke Business & Science ParkSandy LaneYarntonOxford OX5 1PFUKwww.faraday-advance.net

Faraday Advance – one of 24 FaradayPartnerships – is dedicated to improving thecompetitiveness of UK industry throughmore effective interactions between theScience, Engineering and Technology (SET)base in advanced materials and technologiesfor the automotive and aerospace industries.

With six employees, it has an annualturnover of £1.5 million.

Dr Martin Kemp

International Technology Promoter –

Advanced Materials, Europe

DTI Global Watch Service

Pera Innovation ParkMelton MowbrayLeicestershireLE13 0PBUKwww.globalwatchonline.com/itp

The International Technology Promoters (ITP)network, funded through the DTI GlobalWatch Service and managed by PeraInnovation Ltd, is designed to facilitateinternationally based partnerships. The roleof the 18 ITPs is to provide direct assistanceto UK companies in order to raiseawareness of, and provide access to,technology-based opportunities with theworld’s leading investors in R&D.

ITP support ranges from providingstraightforward information and referrals tomore in-depth assistance, perhaps involvingthe setting up of licensing arrangements, orguidance in the early stages of the transferof a product, technology, process or qualityimprovement technique.

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Mr Frank Rott

Assistant Director, Head

DTI Global Watch Service

151 Buckingham Palace RoadLondonSW1W 9SSUKwww.dti.gov.uk www.globalwatchonline.com

The DTI’s Global Watch Service providessupport dedicated to helping UKbusinesses improve their competitivenessby identifying and accessing innovativetechnologies and practices from overseas.The Service comprises:

• INFORMATION – a unique websitedelivering immediate and innovativesupport to UK companies; plus a freemonthly magazine showcasing the latesttechnologies and best practices fromaround the world.

• MISSIONS – enabling small groups of UK experts to visit leading overseastechnology organisations to learn vitallessons about innovation and itsimplementation to benefit entireindustries and individual organisations.

• SECONDMENTS – helping SMEs to sendemployees abroad or receive key peoplefrom overseas, secondments are aneffective way of acquiring knowledge,skills, technologies and connections.

• TECHNOLOGY PARTNERING – free,flexible and direct assistance delivered toUK companies by a network of 18International Technology Promoters (ITPs),providing support ranging from informationand referrals to more in-depth assistance.

Exhibit Page Caption

2.1 9 Mission team at BMW (FIZ), Munich

3.1 10 HPDC cold-chamber process3.2 12 New rheocasting (NRC) process3.3 13 Mission team at the Foundry Institute, RWTH Aachen3.4 14 Rheo-container process (RCP)3.5 15 Rheocasting using cooling channel3.6 15 Cooling channel rheocasting grain morphology3.7 15 Thixocasting process3.8 16 Thixocasting facility at the Foundry Institute3.9 17 Magnesium-MMC infiltrated foam3.10 18 Rheo-diecasting (RDC) process3.11 19 ASTM magnesium die-casting alloy systems and relative performance3.12 19 Performance drivers for magnesium alloy development3.13 21 CO2-snow magnesium melt cover gas development3.14 22 Magnesium up-caster used in EUROMAGUPCASTER3.15 22 Magnesium foam production by low-pressure die-casting (LPDC)

4.1 25 Process window for indirect extrusion of AZ314.2 26 Hydrostatic extrusion process4.3 27 LKR Take-Off project: magnesium PSU rail designs investigated4.4 28 VW 1-litre car, incorporating wrought and cast magnesium4.5 29 Anisotropy of magnesium sheet AZ314.6 29 Typical mechanical properties of magnesium sheet AZ31 4.7 30 Hot-stamped magnesium prototype parts (SZMT and IFUM Hannover)4.8 31 Influence of lubrication on rolling magnesium sheet4.9 32 Forged magnesium demonstration parts

5.1 33 HPDC cross-car beam displaying high levels of part and function integration5.2 35 InMaK: applied research into the manufacture of magnesium structures5.3 35 Laser welding of magnesium sheet: AZ31 (2-mm thick), 7 m/min, 3.3 kW5.4 36 Friction stir welded (FSW) Mg and Mg:Al sheets5.5 37 Cold riveting of AZ31 extrusions, and finite element process simulation5.6 37 LKR co-extrusion research5.7 38 Conventional steel threaded insert used with magnesium HPDCs5.8 38 New thread-forming screw for fastening to magnesium castings5.9 39 New metal foam threaded-insert technology

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Appendix CLIST OF EXHIBITS

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Exhibit Page Caption

6.1 40 Corrosion performance of various magnesium and aluminium alloys6.2 41 PAPVD coating process6.3 42 PECVD coating process6.4 42 Sol-gel coating process6.5 42 Keronite (PEO) process6.6 45 Electrochemical pen used at GKSS to determine corrosion potential6.7 45 Coating evaluation using electrochemical, scanning pen6.8 46 Open circuit potential scan using electrochemical pen to assess free

corrosion potential of FSW of AZ31 magnesium to AA5083 aluminium

7.1 50 Western European consumption of magnesium for die-castings7.2 51 North and South American consumption of magnesium for die-castings7.3 52 Mercedes-Benz 7G-Tronic – seven-speed automatic transmission7.4 53 Traditional HPDC magnesium component applications7.5 53 HPDC magnesium seat frame7.6 53 Magnesium die-cast tailgate inner component and mission team at GKSS

8.1 56 EU-funded R&D projects for structural magnesium

B.1 69 Mission team overviewB.2 69 Mission team at Meridian MPI, Verres, Italy


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µA microampµm micrometre2D two-dimensional3D three-dimensionalAl aluminiumAHC AHC-Oberflächentechnik GmbH (Germany)AMC Australian Magnesium Corp LtdAr argonARC Austrian Research CentresASTM American Society for Testing and Materials (USA)BCAST Brunel Centre for Advanced Solidification Technology (UK)BIW (automobile) body-in-whiteBMBF Bundesministerium für Bildung und Forschung (Germany)ºC degrees CelsiusCa calciumCFK carbon fibre compositeCH3OH methanolCO2 carbon dioxideCr chromiumCr6 hexavalent chromiumCRF Centro Ricerche Fiat (Italy)CTE coefficient of thermal expansionCTI Castings Technology International (UK)Cu copperCVD chemical vapour depositionDC (1) direct-chill (casting); (2) direct currentdm decimetreDTI Department of Trade and Industry (UK)EADS European Aeronautic Defence and Space Company NV (Netherlands)EB electron beamEC European CommissionELV end-of-life vehicleEU European UnionF fluorineFe ironFEA finite element analysis FP4 Framework Programme 4 (EU)FP5 Framework Programme 5 (EU)FP6 Framework Programme 6 (EU)FSW friction stir welding ft footH2 hydrogen

Appendix DGLOSSARY

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H2O waterHAZ heat-affected zone HDO HDO Druckguß- und Oberflächentechnik GmbH (Germany)HIP hot isostatic pressHPDC high-pressure die-castingIFAM Institut für Fertigungstechnik und Angewandte Materialforschung (Germany)IFUM Institut für Umformtechnik und Umformmaschinen (Germany)IMA International Magnesium Association (USA)IP (1) instrument panel; (2) intellectual propertyIPR intellectual property rightsITP International Technology Promoter (DTI)IW Institut für Werkstoffkunde (Germany)kg kilogramkm kilometrekt kilotonnekW kilowattLAFS laser assisted friction stir (welding)LCA life-cycle assessmentLi lithiumLKR Leichtmetallkompetenzzentrum Ranshofen GmbH (subsidiary of ARC)LPDC low-pressure die-castingm metreMEL Magnesium Elektron Ltd (UK)mg milligramMg magnesiumMg2Si magnesium silicide MHz megahertzMIG metal inert gas (welding)min minutemm millimetreMMC metal-matrix compositeMMW molten-metal-waterMn manganeseMPa megapascalmpg miles per gallonMPI Meridian Magnesium Products of Italy srlmpy mils per year (mil = milli-inch = 0.001 inch)MRI Magnesium Research Institute (Israel)mV millivoltNaCl sodium chlorideNd neodymiumNRC new rheocastingNVEB non-vacuum electron beam (welding)O2 oxygenOCH3 methoxy groupOEM original equipment manufacturerPAPVD plasma-assisted physical vapour depositionPECVD plasma-enhanced chemical vapour deposition

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PEO plasma electrolytic oxidationPMZ partially melted zone PRC People's Republic of China PSU passenger stowage unit PVD physical vapour depositionR&D research and developmentRCP rheo container processRDC rheo-diecastingRE rare earth (elements) = lanthanidesRSW resistance spot weldingRTO research and technology organisationRWTH Rheinisch-Westfälische Technische Hochschule (Germany)Sc scandiumSF6 sulphur hexafluorideSi siliconSiO2 silicon dioxide SME small or medium enterpriseSO2 sulphur dioxideSPF superplastic forming SPR self-pierce riveting SSM semi-solid metal SZMT Salzgitter Magnesium-Technologie GmbH (Germany)t tonne (= 1,000 kg)Ti titaniumTiH2 titanium hydrideTIG tungsten inert gas (welding)UK United KingdomULM Ultra Light parts in Magnesium (project, BMBF)US(A) United States (of America)V (1) vanadium; (2) voltVDC vertical downward casting VICT Volvo indoor-cyclic corrosion testVW Volkswageny yearYAG yttrium-aluminium-garnetZn zincZr zirconium

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Global Watch Information

Global Watch Online – a unique internet-enabled service delivering immediate andinnovative support to UK companies in theform of fast-breaking worldwide business andtechnology information. The website providesunique coverage of DTI, European andinternational research plus businessinitiatives, collaborative programmes andfunding sources.Visit: www.globalwatchonline.com

Global Watch magazine – the website’s sisterpublication, featuring innovation in action.Distributed free to over 30,000 UK recipients,this monthly magazine features the latesttechnology developments and practicesgleaned from Global Watch Service activitiesaround the world now being put into practicefor profit by British businesses.Contact: [email protected]

UKWatch magazine – a quarterly magazine,published jointly by science and technologygroups of the UK Government. HighlightingUK innovation and promoting inwardinvestment opportunities into the UK, thepublication is available free of charge to UKand overseas subscribers.Contact: [email protected]

Global Watch Missions – enabling teams ofUK experts to investigate innovation and itsimplementation at first hand. The technologyfocused missions allow UK sectors andindividual organisations to gain internationalinsights to guide their own strategies forsuccess.Contact: [email protected]

Global Watch Secondments – helping smalland medium sized companies to sendemployees abroad or receive key people fromanother country. Secondments are aneffective way of acquiring the knowledge,skills, technology and connections essentialto developing a business strategically.Contact:[email protected]

Global Watch Technology Partnering –providing free, flexible and direct assistancefrom international technology specialists toraise awareness of, and provide access to,technology and collaborative opportunitiesoverseas. Delivered to UK companies by anetwork of 18 International TechnologyPromoters, with some 6,000 currentcontacts, providing support ranging frominformation and referrals to more in-depthassistance with licensing arrangements andtechnology transfer.Contact: [email protected]

For further information on the Global WatchService please visitwww.globalwatchonline.com

The DTI’s Global Watch Service provides support dedicatedto helping UK businesses improve their competitivenessby identifying and accessing innovative technologies andpractices from overseas.

Printed in the UK on recycled paper with 75% de-inked post-consumer waste content

First published February 2005 by Pera Innovation Limited on behalf of the Department of Trade and Industry

© Crown copyright 2005

URN 05/538

MAG TECH 1 Magnesium

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