Stakalloy is a

ternary alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...

uranium Uranium is a chemical element with the 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. Uranium is weakly ...

composed of

vanadium Vanadium is a chemical element with the 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 oxide layer ( pass ...

niobium Niobium is a chemical element with chemical symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, and it ha ...

, 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 than natural uranium.: "Depleted uranium possesses only 60% of the radioactivity of natural uranium, ...

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

Loyola University Maryland Loyola University Maryland is a private Jesuit university in Baltimore, Maryland. Established as Loyola College in Maryland by John Early and eight other members of the Society of Jesus in 1852, it is the ninth-oldest Jesuit college in the ...

under grant from the United States Army.

Composition

The niobium content of stakalloy is between 0.01 to 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 sci ...

properties over other depleted uranium alloys, such as

staballoy ] Staballoy is the name of two different classes of metal alloys, one class typically used for munitions and a different class developed for drilling rods. Kinetic penetrators In a military context, staballoys are metal alloys of a high proportion ...

, being more viable as a structural alloy where a combination between Strength of materials, high strength and high density is required. Changes include that of density,

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion (mechanical), abrasion. In general, different materials differ in their hardn ...

, ballistic properties, and machinability.

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 a ...

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 ceramic or metal container in which metals or other substances may be melted or subjected to very high temperatures. While crucibles were historically usually made from clay, they can be made from any material that withstands te ...

. 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