Military Applications for Beta Ti Alloys TMS 2005...J. C. Fanning, Military Applications for Beta Ti...

J. C. Fanning, Military Applications for Beta Ti Alloys ITA 2005

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MILITARY APPLICATIONS FOR BETA TITANIUM ALLOYS

John FanningTIMET Henderson Technical Lab

Henderson, NV

TITANIUM 2005Scottsdale, AZ

September 25 – 27, 2005


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Two R&D Thrusts for Ti in Military Applications:

1. Reduced cost, improved availability and consistent ballistic performance for Ti-6Al-4V

• Electron Beam Single Melting• Thermomechanical Processing Development

2. Advanced alloys with improved properties.• Armor• Mortars and Missile Tubes

Focus of this presentation


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Outline

• Ballistic Protection– Armor Piercing Projectiles– Ball Projectiles– Sharp Instruments

• Mortar Barrels• Missile Launch Canisters


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Ballistic Protection Against AP ProjectilesTest Method

.30 (7.62mm) AP M2 Projectile


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Ballistic Protection Against AP ProjectilesTest Method (cont.)

Test Range Configuration forBallistic Limit Testing of Titanium Plates

NOT TO SCALE

4.6m (15 ft) 15.2m (50 ft) 3.0m (10 ft)152mm

TargetWeaponor Barrel

1st ScreenWitnessPlate

2nd ScreenChronograph

Line of Fire


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Ballistic Protection Against AP Projectiles Ballistic Test Results

V50 Ballistic Limit vs. Titanium Alloy Plate ThicknessResults for Ti-6Al-4V Only

0

400

800

1200

1600

2000

2400

2800

3200

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.9Plate Thickness, in

V50

, fee

t/sec

ond

TIMETAL 6-4 (Ti-6Al-4V)

Linear Fit for TIMETAL 6-4


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V50 Ballistic Limit vs. Titanium Alloy Plate ThicknessResults for Ti-6Al-4V and Beta Alloys

0

400

800

1200

1600

2000

2400

2800

3200


V50

, fee

t/sec

ond

TIMETAL 555 (Ti-5.5Al-5V-5Mo-3Cr-0.12O) STA

TIMETAL 15-3 (Ti-15V-3Cr-3Sn-3Al-0.12O) STA

VST3553+Zr (Ti-3Al-5V-3Cr-0.4Zr) STA

TIMETAL 6-4 (Ti-6Al-4V)

Linear Fit for TIMETAL 6-4


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V50 Ballistic Limit vs. Titanium Alloy Plate ThicknessResults for Ti-6Al-4V and Beta Alloys

0

400

800

1200

1600

2000

2400

2800

3200


V50

, fee

t/sec

ond

TIMETAL 555 (Ti-5.5Al-5V-5Mo-3Cr-0.12O) STATIMETAL 15-3 (Ti-15V-3Cr-3Sn-3Al-0.12O) STATIMETAL LCB (Ti-6.8Mo-4.5Fe-1.5Al) STAVST3553+Zr (Ti-3Al-5V-3Cr-0.4Zr) STATIMETAL 6-4 (Ti-6Al-4V)Linear Fit for TIMETAL 6-4


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Ballistic Mass Efficiency of Beta Alloys Compared to Ti-6Al-4V for .30 (7.62mm) AP M2 Projectiles

Alloy Mass g cm-3 lbs in-3 Efficiency

Ti-6Al-4V 4.46 0.161 1.00

Ti-5.5Al-5V-5Mo-3Cr-0.12O [555] STA 4.65 0.168 0.97

VST3553+0.6Zr STA 4.65 0.168 0.86

Ti-6.8Mo-4.5Fe-1.5Al [LCB] STA 4.79 0.173 0.66

Ti-15V-3Cr-3Sn-3Al-0.12O [15-3] STA 4.79 0.173 0.90

STA = Solution Heat Treated + Aged

Density


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Consideration of Failure Modes

Ti-6Al-4V defeats AP projectiles by entrapment only (core of projectile is not usually damaged).

Although hardenable titanium alloys have relatively low mass efficiencies as monolithic armor, some alloys (such as TIMETAL LCB) have shown an ability to fracture AP projectiles in some test conditions. This might offer benefits in some multilayer systems.

Ballistic Protection Against AP Projectiles


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Entrapment of .30 (7.62mm) AP M2 Projectile in Ti-6Al-4V Plate

5mm


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High partial penetration of LCB monolithic plate after testing against .30 (7.62mm) AP M2

BACK

0.25-in(6.4mm)

FRONT

0.25-in(6.4mm)

Remnant .30 AP M2 Projectile


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Ballistic Protection Against Ball Projectiles

TIMETAL 15-3 plate backed with aramid fabric was tested against 7.62 x 39mm M43 Soviet (7.96g [ 123 gr.]; FMJ, mild steel core) ammunition.

Results were better than that of a less titanium-intensive system that consisted of a thin sheet of Ti-6Al-4V backed by a greater thickness ofaramid fabric.

Note that even though the system areal densities were roughly the same, the titanium-intensive system had a significantly higher V50. The ability of the TIMETAL 15-3 plate to damage the mild steel components of the projectiles potentially provides performance advantages in some systems.


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4.8mm TIMETAL 15-3 plus aramid fabric.Areal Density = 30 kg m-2 (6.2 psf)

V50 = 721 m s-1 (2365 fps)

2.0mm TIMETAL 6-4 plus aramid fabric.Areal Density = 28 kg m-2 (5.8 psf)

V50 = 484 m s-1 (1579 fps)

6 mm

Ballistic Protection Against Ball Projectiles

Effect of Proportion of Titanium on Performance of ArmorResidual Projectiles After Testing Against 7.62x39mm


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Mortar Barrels

• Candidate Lightweight Materials:– Aluminum– Titanium – Composites


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Mortar Barrels

To reduce the weight of the barrel on the 81mm M253 mortar, a TIMETAL 21S mortar barrel was designed, manufactured and tested by the U.S. Army

Titanium was selected instead of aluminum or graphite reinforced epoxy composites based on computational modeling of the thermal and mechanical characteristics of a lightweight mortar tube constructed from each of the candidate materials.

In all cases, it was assumed that the interior of the tube would contain a steel liner for direct contact with the projectile.

REF:L. Burton, “Analysis of Titanium-Sheathed 81-mm Mortar Barrel”


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Tensile Properties of TIMETAL 21S Plate at Elevated Temperature (SI)

0100200300400500600700800900

10001100120013001400

-100 0 100 200 300 400 500 600 700 800 900 1000 1100

Test Temperature, C

Stre

ngth

, MP

a

0

12

24

36

48

60

72

84

96

108

120

Elo

ngat

ion,

%

UTSTYSElong


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Tensile Properties of TIMETAL 21S Plate at Elevated Temperature (ENG)

0

20

40

60

80

100

120

140

160

180

200

-200 0 200 400 600 800 1000 1200 1400 1600 1800 2000

Test Temperature, F

Stre

ngth

, ksi

0

12

24

36

48

60

72

84

96

108

120

Elon

gatio

n, %

UTSTYSElong


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Mortar Barrels

Prototype TIMETAL 21S Mortar Barrel

REF:L. Burton, “Analysis of Titanium-Sheathed 81-mm Mortar Barrel”


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Concentric Canister Launcher

TIMETAL 21S and other titanium alloys were evaluated for a Concentric Canister Launcher (CCL) for the Mk41 Vertical Launch System (VLS)

A prototype titanium CCL was manufactured and tested with a hemispherical head made from TIMETAL 21S.

Although the results were favorable, titanium has not yet been incorporated in this design concept.

REF: R.S. Rosen, R. W. Lowry and M.E. Kassner, “High Temperature Properties of Alloys Being Considered for Design of a Concentric Canister Launcher”


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AUXILIARYVIEW

EXHAUST PRODUCTSFLOW THROUGHANNULAR SPACE



HEMISPHERICAL HEAD MADE FROM TIMETAL 21S (ON PROTOTYPE)


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Effect of test temperature and strain rate on the yield strength at very high temperatures

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1E-3 10E-3 1E-3 10E-3

2000F 2000F 2400F 2400FStrain Rate (Top Row) and Test Temperature (Bottom Row)

0.2%

Yie

ld S

tress

, ksi

TIMETAL 21S

TIMETAL 15-3

Beta C

Ti-6Al-4V



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Effect of test temperature and strain rate on the yield strength at very high temperatures

0

4

8

12

16

20

24

28

1E-3 10E-3 1E-3 10E-3

1093C 1093C 1316C 1316CStrain Rate (Top Row) and Test Temperature (Bottom Row)

0.2%

Yie

ld S

tress

, MP

a

TIMETAL 21S

TIMETAL 15-3

Beta C

Ti-6Al-4V



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Summary

• Beta titanium alloys have mechanical, physical and ballistic properties potentially of interest in a variety of non-aerospace military applications. As discussed in this paper, observations of interest so far include:

• As monolithic armor, the ballistic performance of beta alloys is generally less than that of Ti-6Al-4V. However, the higher strength and hardness of beta alloys may offer advantages in certain types of armor systems for armor piercing projectiles.

• TIMETAL 15-3 plate backed with aramid fabric can provide an effective system for defeating ball ammunition.


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Summary (cont.)

• The good elevated temperature properties of TIMETAL 21S make it potentially suitable for mortar barrel and missile launch canister applications.

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Military Applications for Beta Ti Alloys TMS 2005...J. C. Fanning, Military Applications for Beta Ti...

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