TITANIUM ALLOYS FOR ARMOR APPLICATIONS Matthew … · Introduction • Titanium was first...
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TITANIUM ALLOYS FOR ARMOR APPLICATIONS Matthew Burkins, U.S. Army Research Laboratory Titanium alloys have long been used for reducing system weight in aerospace components. The high cost of titanium, however, has historically prevented the application to military ground vehicles. In recent years, the cost of titanium has fallen relative to the cost of composite and ceramic armors and titanium is now a valid option for some Army systems. The advantages of low density, high strength, a large competitive industrial base, and mature forming and shaping techniques make titanium an excellent choice for many military applications. The U.S. Army Research Laboratory has invested significant research efforts in understanding the material processing requirements for ground applications and this paper will provide an overview of that research. Major efforts have been investigating alternative alloys and amending existing military specifications to allow the use of alternative and lower cost alloys that meet specific ground applications.
Transcript of TITANIUM ALLOYS FOR ARMOR APPLICATIONS Matthew … · Introduction • Titanium was first...
TITANIUM ALLOYS FOR ARMOR APPLICATIONS
Matthew Burkins, U.S. Army Research Laboratory
Titanium alloys have long been used for reducing system weight in aerospace components. The high cost of titanium, however, has historically prevented the application to military ground vehicles. In recent years, the cost of titanium has fallen relative to the cost of composite and ceramic armors and titanium is now a valid option for some Army systems. The advantages of low density, high strength, a large competitive industrial base, and mature forming and shaping techniques make titanium an excellent choice for many military applications. The U.S. Army Research Laboratory has invested significant research efforts in understanding the material processing requirements for ground applications and this paper will provide an overview of that research. Major efforts have been investigating alternative alloys and amending existing military specifications to allow the use of alternative and lower cost alloys that meet specific ground applications.
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THE DESIGN AND APPLICATION OF TITANIUM ALLOYS FOR US ARMY
PLATFORMSPLATFORMS
MILITARY PANEL
September 24, 2008
Matthew BurkinsU.S. Army Research Laboratory
Weapons and Materials Research Directorate
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Aberdeen Proving Ground, MD 21005-5066
Introduction
• Titanium was first investigated for armor use in 1950 by theWatertown Arsenal and Ti-6Al-4V became the main alloy ofinterest
• The main advantage of titanium is the reduced density at highstrength when compared with Rolled Homogeneous Armor(RHA) steel.
• Military Specification MIL-DTL-46077 sets the requirements forTi-6Al-4V for armor applications. A large portion of thispresentation will discuss recent revisions to this specification.p p
• This presentation will also examine some of the processingissues that impact on the use of titanium for ground platforms.
• The presentation will close with a brief overview of some currentand proposed applications of titanium in military groundvehicles.
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Titanium Alloys
Alpha-BetaTi-6Al-4V
BetaTi-10V-2Fe-3Al
AlphaCP Ti Gr 1-4 Ti 6Al 4V
110-120 ksiTi 10V 2Fe 3Al
170 ksiCP Ti Gr 1 4
35-80 ksi(0.18-0.40% O2)
• Structures • Torsion bars• ArchitecturalPi i • Armor • Springs• Piping
Ductility, Weldability, Corrosion resistance, creep strength
Tensile strength Density Fabricability Heat treatability3
Tensile strength, Density, Fabricability, Heat treatability
MIL-DTL-46077 Armor (Version F & G)
Chemistry Max. O2Content
Comments
Class 1 6AL- 4V 0.14% ELI-10% Elongation Min.
Cl 2 6AL 4V 0 20% C AClass 2 6AL- 4V 0.20% Common Armor6% Elongation Min.
Class 3 6AL- 4V 0 30% High Scrap ContentClass 3 6AL 4V 0.30% High Scrap ContentWeld & cold temp issues
Class 4 Not 0.30% For future Limited developments
All 4 classes have the same min. strength 4
gand ballistic requirements.
MIL-DTL-46077F Ballistic Requirements
Thickness Ranges(inches)
Ballistic Test Projectile(inches) Projectile
0.25 to 0.615, excl .30 cal. AP M2
20 FSP0.615 to 1.575, excl
20mm FSP(Fragment Simulating Projectile)j )
1.575 to 1.950, excl 14.5mm API B321.950 to 4.000 20mm API-T M602950 to 000 0 60
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Effect of Annealing Temperature
1200
1100
Y (m
/s)
1.125” Ti-6Al-4V ELI plate
900
1000
VE
LOC
ITY
s
5 6 p ate
V50 testing with 20mm FSP
800
VCFOnly, NoAnneal30Min Anneal, AC30Min Anneal, WQ30Min Anneal, FC120Min Anneal, ACDuplex (1038+788)
V50
LIM
IT
Bet
a Tr
ansu
700700 800 900 1000 1100
Duplex (1038+788)
6ANNEALINGTEMPERATURE (C)
Burkins, Love, & Wood, Effect of Annealing Temperature on the Ballistic Limit Velocity of Ti-6Al-4V ELI, ARL-MR-359, August 1997.
Charpy V-Notch Results
1200
L 27J1100
Y (m
/s)
L- 27J T- 29J
L- 22J
900
1000
VE
LOC
ITY
s
T- 20JL- 46J T- 45J
800
VCFOnly, NoAnneal30Min Anneal, AC30Min Anneal, WQ30Min Anneal, FC120Min Anneal, ACDuplex (1038+788)
V50
LIM
IT
Bet
a Tr
ansu
700700 800 900 1000 1100
Duplex (1038+788)
7ANNEALINGTEMPERATURE (C)
Burkins, Love, & Wood, Effect of Annealing Temperature on the Ballistic Limit Velocity of Ti-6Al-4V ELI, ARL-MR-359, August 1997.
Bottom Line
Low strain rate mechanicalLow strain rate mechanical properties provide no
t f b lli tiguarantee for ballistic performance!
That’s why military armorThat s why military armor specifications were developed.
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MIL-DTL-46077G Ballistic Requirements
Thickness Ranges(inches)
Ballistic Test Projectile(inches) Projectile
0.125 to 0.249 To be determined0 25 to 0 614 30 cal AP M20.25 to 0.614 .30 cal. AP M2
0.615 to 1.57420mm FSP(Fragment Simulating Projectile)
1.575 to 1.949 14.5mm API B321 950 t 3 249 20 API T M6021.950 to 3.249 20mm API-T M6023.250 to 4.000 30mm APDS
Q lit h i d t th i t h th 209
Quality has improved to the point where the 20mm can’t defeat some thicknesses!
Beta Processing Concerns
• Beta processing can be controlled or avoided in wrought plate andwrought plate and forgings.
• Beta processing is unavoidable for welds, castings and somecastings, and some powder metallurgy processes.
Designs must include additional thickness(~10 20%) to offset reduced performance
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(~10-20%) to offset reduced performance.
Titanium Welding
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Ballistic Welds
W ld l f th• Welds always perform worse than parent metal
• Titanium needs a standard to insure weldments withstand ballistic shock– Similar to MIL-STD-1941 for steel and
MIL-STD-1946 for aluminum– Non-penetrating impact by large, blunt
projectile traveling at low velocity
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Performance of Different Alloys
1000
980
VELO
CIT
Y
960
EDV
50L I
MIT
V
920
940
.30 cal. Ball M2
.30 cal. FSPNORM
ALIZ
E
900
920
100 110 120 130 140 150 160 170 180 190 200
Beta AlloysTi-6-6-2Ti-6-4Ti-6-4ELI
Ti-6-4ELI Ti-6-4 Ti-6-6-2 Beta Alloys
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100 110 120 130 140 150 160 170 180 190 200
0.2% YIELD STRENGTH (ksi)
Dual Hardness Titanium
Ti-6Al-4V CP Ti Gr 2
Beta Alloy Ti-6Al-4V
Combine a hard and soft alloy together t i f
14to improve performance.
Titanium Armor for Ground Vehicles
Proposed as modular armor for 5 Ton T k d i th K WTrucks during the Korean War
Steel used due to cost and availability issues15
Steel used due to cost and availability issues.
Charles Hickey, MTL, Titanium in the Lightweight Mobile Army, briefing to Mr Jerome Persh, Aug 1991.
Current Applications
Titanium Weight Reduction Program for M1A2 Abrams Battle Tank
Bustle BlowBustle Blow--off Panels off Panels 182182 lb Weight Reductionlb Weight Reduction
Bustle BlowBustle Blow--off Panels off Panels 182182 lb Weight Reductionlb Weight Reduction
GunnerGunner’’s Primary Sight Covers Primary Sight Cover147147 lb Weight Reductionlb Weight Reduction
GunnerGunner’’s Primary Sight Covers Primary Sight Cover147147 lb Weight Reductionlb Weight Reduction
Internal Armor ChangesInternal Armor Changes11001100 lb Weight Reductionlb Weight Reduction NBC System CoversNBC System CoversInternal Armor ChangesInternal Armor Changes11001100 lb Weight Reductionlb Weight Reduction NBC System CoversNBC System Covers
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11001100 lb Weight Reductionlb Weight Reduction 8181 lb Weight Reductionlb Weight Reduction11001100 lb Weight Reductionlb Weight Reduction 8181 lb Weight Reductionlb Weight Reduction
GDLS >1500 lbs weight savings
Current Applications
Titanium Commander Hatch and Roof Applique on M2A2 Bradley Fighting Vehicle
Commander’s Hatch Turret Roof Applique
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Current Applications
Ultra-light Weight M777A1 Towed Howitzer Utilizes Extensive Titanium Castings and Plateg
18>7000lbs savings over M198
Future Applications
Pegasus Titanium Wheeled Prototype
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Future Applications
Future Combat Vehicle Titanium Hull Prototype
20ARL & BAE
Conclusions
• This presentation has provided a cursory overview of the technicalinvestigation of titanium for military ground applications
• The main advantage of titanium relates to the lower density (lower arealdensity) at equal or higher strengths than rolled homogenous armorsteel of equal thickness
• The current Military Specification MIL-DTL-46077G was discussed
• The importance of processing temperatures has been emphasized inmany slides particularly processing over the Beta Transus of Ti-6Al-4Vmany slides, particularly processing over the Beta Transus of Ti 6Al 4V
• The presentation has ended with a few of current and proposed futureapplications of titanium in military ground vehicles
• Requirements to reduce combat weights drives applications towards thelower density materials that have excellent ballistic properties
Thank you
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Thank you
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