Stakalloy is a ternary alloy of

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

composed of

vanadium Vanadium is a chemical element; it has Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

, and

depleted uranium Depleted uranium (DU), also referred to in the past as Q-metal, depletalloy, or D-38, is uranium with a lower content of the fissile isotope Uranium-235, 235U than natural uranium. The less radioactive and non-fissile Uranium-238, 238U is the m ...

. The alloy was developed in 2002 by Michael R. Staker of

Loyola University Maryland Loyola University Maryland is a Private university, private Society of Jesus, Jesuit university in Baltimore, Maryland. Established as Loyola College in Maryland by John Early (educator), John Early and eight other members of the Society of Je ...

under grant from the United States Army.

Composition

The niobium content of stakalloy is between 0.01 and 0.95 percent by weight and the balance being uranium. The vanadium content of the alloy is between the gamma eutectoid and the eutectic compositions, 1.0 percent and 4.5 percent by weight respectively.

Properties

Stakalloy has improved

metallurgical Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the ...

properties over other depleted uranium alloys, such as staballoy, being more viable as a structural alloy where a combination between high strength and

high density High may refer to: Science and technology * Height * High (atmospheric), a high-pressure area * High (computability), a quality of a Turing degree, in computability theory * High (tectonics), in geology an area where relative tectonic uplift t ...

is required. Changes include that of density,

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by Pressing (metalworking), pressing or abrasion ...

, ballistic properties, and

machinability Machinability is the ease with which a metal can be cut ( machined) permitting the removal of the material with a satisfactory finish at low cost.Degarmo, p. 542. Materials with good machinability (free-machining materials) require little power t ...

Production

Staker's invention of stakalloy involved reducing excessive carbon levels while adding together uranium with trace amounts of niobium and vanadium. The three constituent parts may be combined through melting, however, the niobium and vanadium must be charged into the melt or introduced to additional melt stock before heat-up.

Arc melting An electric arc furnace (EAF) is a furnace that heats material by means of an electric arc. Industrial arc furnaces range in size from small units of approximately one-tonne capacity (used in foundries for producing cast iron products) up to ...

is also a melting technique noted by Staker, in which niobium is added to an alloy of vanadium and uranium from a

crucible A crucible is a container in which metals or other substances may be melted or subjected to very high temperatures. Although crucibles have historically tended to be made out of clay, they can be made from any material that withstands temperat ...

. After casting an ingot of stakalloy, the ingot can be used in the as-cast condition or be worked—either hot or cold—to change both properties and shape. Stakalloy can also be heat-treated after manipulation of shape.

Uses

Stakalloy may be a viable replacement for the United States Army's Advanced Kinetic Energy round. In 2007, Army Solicitation Notice W911QX-07-T-0053 entitled "Processing U-V-X Alloy Ingots" outlined work at

Aerojet Aerojet was an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California, with divisions in Redmond, Washington, Orange and Gainesville in Virginia, and Camden, Arkansas. Aerojet was owned by GenCorp, ...

producing promising alloys with interesting material properties for future testing at the Army Research Laboratories.

References

{{reflist Alloys