US3773569A

US3773569A - Process of making high strength,high density,highly ductile uranium-titanium alloy

Info

Publication number: US3773569A
Application number: US00185812A
Authority: US
Inventors: R Edelman; A Saia
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1971-10-01
Filing date: 1971-10-01
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20

Abstract

The step of furnace tempering a solution treated, waterquenched, worked cast ingot at 600*F for about 4 hours in an inert atmosphere and permitting the ingot to furnace cool in that atmosphere yields an uranium-1.25 titanium alloy having the following physical properties: Tensile strength : 234,700 psi Yield strength : 172,700 psi Elongation in 1 inch : 17% Nominal density : 18.

Description

2:1: atent [191 Edelm et a represented by the Secretary of the Army, Washington, DC.

[22] Filed: Oct. 1, 1971 [21] Appl. No.: 185,812

[52] US. Cl. 148/ll.5 F, 102/52, 148/132 [51] Int. Cl C2ld 1/18, F42b 11/14 [58] Field of Search 148/132, 11.5 R,

[56] References Cited OTHER PUBLICATIONS Douglass et aL, Effect of Heat Treatment on the Hard- Nov. 20, 1973 ness and Microstructure of U-Ti Alloys, in J. Met. 9:1. 1260-1267, Oct. 1957.

Primary Examiner--Carl D. Quarforth Assistant Examiner-R. E. Schafer Attorney-Harry M. Saragovitz et al.

[57 ABSTRACT The step of furnace tempering a solution treated, water-quenched, worked cast ingot at 600F for about 4 hours in an inert atmosphere and permitting the ingot to furnace cool in that atmosphere yields an uranium- 1.25 titanium alloy having the following physical properties:

Tensile strength 234,700 psi Yield strength 172,700 psi Elongation in 1 inch 17% Nominal density 18.5g/cc 6 Claims, No Drawings PROCESS OF MAKING HIGH STRENGTH, HIGH DENSITY, HIGHLY DUCTILE URANIUM-TITANIUM ALLOY The invention described herein may be manufacduction furnace at room temperature, the furnace temperature then being brought to about 2,800F and held at this temperature until the melt is substantially homogeneous.

tured, used, and licensed by or for the Government for 5 Thc titanium will preferably comprise L25 we'ght governmental purposes without the payment to us of percent 9 the alloy but may range m {about to any royalty thereon 1.40 weight percent thereof. lf quantities less than This invention relates to alloys and more particularly about we'ght percent f g i we gi concerns processes for fabricating a high strength, high I 0 found C ac li g f or density, highly ductile uranium-titanium alloy. armor'plercmg onverse w en t e mamum exceeds about 1.40 weight percent of the alloy, an un- Armor-piercing pro ectiles and the like for modern desirably brittle piece results. day munitions must be strong, ductile, and of high den- Sit The melt may now be poured into another mold, suitzy t td th ably magnesia, alundum, thoria, and the like, to form I i uc l I e armortplercmg ,pene' a rod or bar shaped casting of desired dimensions. This "atolmlght fragment or fracture. upon with an cast ingot will now be worked, by extrusion, forging, enemy target the target compnses but Smgle armor rolling, etc. and then subjected to a heat treatment as layer, fragmenting of the penetrator upon impact therefollows, with might not be unduly detrimental. Where, however, solution treat the worked cast ingot at 0 0 enemy targets compnse spced armof F x m for about 16 hours. The ingot may be placed in the vacmany modem tanks a flymg craft It lmiferatwe uum furnace while maintained at room temperature or that the armor-piercing penetrator remain integral at the desired end temperature of o 7 o upon impact if successful penetration of the layers is to The Solution treated ingot will the be removed from be acheved' the vacuum furnace and immediately water quenched i' i the armor'plercfng molecules must be prior to a tempering treatment which comprises placing sufficiently strong to withstand impact and be of suffithe quenched ingot alloy in a furnace maintained at ciently high density to render them capable ofpenetratroom temperature comaining an inert atmosphere, ing these enemy targets. In thls regard, prior art armorpreferably heliunL The furnace is brought up to 0 P g penetratorS and proiectlles do not P0556SS in about 1 hour, held for 4 more hours, and permitted high strength, high density and high ductility properties to cool to about room temperature in about hours, Yequll'ed of modem y munmonsthe inert atmosphere being maintained throughout. It it is therefore an object Of thlS invention to provide is this tempering o ageing step is considered an alloy having high Strength. g density, and hlgh vital in the retention of desired ductility and strength. ductility- More specifically, our melt was cast into ingots hav- Another object of the invention is to provide such an i a di f 2 d a l th f b t 3 i h alloy which would make it ideally suitable for armOr- Th were forged in air at approximately 1650F into piercing capabilities. 3 1 inch diameter rods, then hot swaged at approxi- The exact nature of this invention as well as other obmately 1650F t ya i h diam t They w then majects and advantag s there f ll be e i y app chined to remove the forged surfaces prior to the heat from consideration of the specification that follows. 40 treatment above described.

ln accordance with the above objects, we have dis- Tensile bars were cut from these heat treated bars. covered that a uranium base alloy which includes a The table below lists various mechanical properties of minor proportion of titanium, will yield a highly ductile these specimens for our preferred alloy composition.

TABLE I High strength, high ductility, high density U-TI alloy Tensile Yield Nominal strength, strength, Elongation in density, Number Alloy Heat treatment p.s.i. p.s.i. 1 g./cc.

i 98.75U1.25Ti. 1,650l.700 F.16 hours in vacuo; water quenched; 600 F.-4 hours 234, 700 172, 700 17% 18.5

(helium); furnace cooled in helium. .2 98.75U1.25Ii Same as No. 1, except specimen air cooled instead of furnace cooled 200,000 176,000 7.2% 18. 5 154,000 l'oke bn'ttely.- 18.5

3 98.76U1.25Ti. Same as No. 2, except Water quenched alloy having good strength and density when said alloy is made in accordance with our process steps.

More specifically, we have found that when about 1.25 weight percent titanium is alloyed with the uranium, an alloy can be formed when using our inventive process steps having a tensile strength of 234,700 psi; a yield strength of l72,700 psi; an elongation in 1 inch of 17 percent; and a nominal density of about 18.5g/cc.

ln producing our inventive alloy, we place a measured quantity of commercial, high purity (99.9 percent) uranium dingot at the bottom of a crucible, suitably of magnesia or graphite+ceramic-wash, and titanium sponge of commercial purity thereabove, the crucible and contents then being placed in a vacuum in- We wish it to be understood that we do not desire to I be limited to the exact details described, for obvious tempering said quenched ingot alloy at 600F for a period of about 4 hours in an inert atmosphere,

furnace cooling said tempered ingot alloy in said inert atmosphere. and

shaping said cooled tempered ingot alloy into said armor-piercmg munition.

2. The process as described in claim 1 wherein said titanium is present in said alloy in an amount of 1.25 weight percent, the balance being substantially uranium, and wherein tensile strength of said alloy is about 234,700 psi, yield strength of said alloy is about 172,700 psi, elongation in 1 inch of said alloy is about 17 percent and nominal density of said alloy is about 18.5g/cc.

3. The process as described in claim 2 wherein said worked ingot comprises the steps of forging said ingot in air at about 1,650F, and hot swaging said forged ingot prior to said solution treatment. 4. The process as described in claim 2 further characterized by said inert atmosphere being helium.

5. The process as described in claim 2 further characterized by said tempering step comprising placing said water quenched ingot in a furnace maintained at room temperature in said inert atmosphere, raising the temperature of said furnace to about 600F in a period of about 1 hour while maintaining said inert atmosphere. 6. The process as described in claim 5 further characterized by said inert atmosphere being helium.

Claims

2. The process as described in claim 1 wherein said titanium is present in said alloy in an amount of 1.25 weight percent, the balance being substantially uranium, and wherein tensile strength of said alloy is about 234,700 psi, yield strength of said alloy is about 172,700 psi, elongation in 1 inch of said alloy is about 17 percent and nominal density of said alloy is about 18.5g/cc.
3. The process as described in claim 2 wherein said worked ingot comprises the steps of forging said ingot in air at about 1,650*F, and hot swaging said forged ingot prior to said solution treatment.
4. The process as described in claim 2 further characterized by said inert atmosphere being helium.
5. The process as described in claim 2 further characterized by said tempering step comprising placing said water quenched ingot in a furnace maintained at room temperature in said inert atmosphere, raising the temperature of said furnace to about 600*F in a period of about 1 hour while maintaining said inert atmosphere.
6. The process as described in claim 5 further characterized by said inert atmosphere being helium.