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87Fraunhofer Institute for Laser Technology ILT, www.ilt.fraunhofer.de

DQS certified by DIN EN ISO 9001, Reg.-No.: DE-69572-01

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3 Typical application, source: MEV.

4 Long-exposure image of illuminated

powder layer during SLM.

approaching 100 percent. The next step is to study the

mechanical properties. Initial results indicate that very high

strengths can be achieved (Rm and Rp 0.2 approx. 500 MPa),

accompanied by high elongations at rupture (A approx.

20 percent). Compared with SLM components made of

AlSi10Mg, the yield strength Rp 0.2 is approx. 200 percent

higher and the elongation at rupture approx. 400 percent

higher. Aerospace components are frequently subjected

to dynamic loads, which are currently being tested in an

exhaustive series of fatigue tests. Initial results indicate that

test specimens made of AlMgScZr possess greater dynamic

strength than components made of AlSi10Mg.

In future studies, we aim to determine whether it is possible

to increase component strength still further by increasing

the Sc or Mg content of the alloy and by increasing the SLM

process cooling rate. Other potential means of reducing

component weight include optimizing component topology

and its manufacture by SLM.

contacts

Dipl. -Ing. Damien Buchbinder

Phone +49 241 8906-488

[email protected]

Dr. Konrad Wissenbach

Phone +49 241 8906-147

[email protected]

task

Two die-casting alloys, AlSi10Mg and AlSi9Cu3, have already

been qualified at Fraunhofer ILT for the additive manufacturing

of aluminum components by Selective Laser Melting (SLM).

The aerospace industry has a need for high-strength aluminum

components that are suitable for lightweight construction and

at the same time meet the requirements for structural durabi-

lity and corrosion resistance. An innovative alloy (Scalmalloy®)

was investigated as a possible solution. AlMgScZr is a material

that combines the good corrosion resistance and welding

properties of AlMg alloys with the increased strength offered

by precipitation hardening (Al3Sc(+Zr) phase). The higher

strength of this material is the result of rapid cooling from the

molten state. Previous studies demonstrate the viability of melt

spinning in this context (cooling rate 104 to 106 K/s). It has

been typically applied to extruded parts.

Using SLM with the same range of cooling rates will

enable the manufacture of complex 3-D parts with increased

strength, a task that was previously not possible.

Result and applications

The primary objective when qualifying a material for SLM is to

obtain a component density approaching 100 percent without

any cracks, fusion defects or pores. This involves evaluating

the process parameters, especially scanning velocity and laser

output power, required to produce components with a density

addITIve ManufacTurIng of hIgh-sTrengTh aLuMInuM coMPonenTs

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