Controlled Atomsphere Plasma Spray Forming of Claddings for High K-E Tungsten Penetrators

The replacement of depleted uranium (DU) by tungsten alloys with plasma spray formed claddings is proposed. Such claddings would force highly localized shear to be continually induced by employing a thick adiabatic shear-susceptible coating or cladding on tungsten alloy cores. This cladding or composite approach enables optimal shear performance to be developed in an alloy or cladding structure without compromising the ballistic performance of the core tungsten penetrator. Chamber or vacuum plasma spray forming in controlled atmospheres (low pressure or inert gas) will be used to produce such thick claddings from powders of alloys which intrinsically exhibit highly localized, adiabatic shear. Plasma sprayed claddings of tool steels, intermetallics and titanium will be evaluated. Another method of achieving highly localized shear band deformation is through a combination of alloy and microstructure (composite/micro-laminate) whicha re plasma sprayed. Such microstructure-induced shear systems which consist of micro-laminate layered structures with alternating layers of a base alloy such as tungsten, tool steel, or titanium with TiC, zirconia, or nickel aluminide layers will also be studied. The particualte and layer processing capability of plasma spray forming lends itself to the formation of such alloys and structural claddings onto tungsten penetrator cores. The challenge will be to achieve sufficient bonding and strain compatibility between the cladding adn tungsten core. Controlled atmosphere plasma spray has the potential to improve the bond, especially with post-spray heat treatments and by grading interfaces to accommodate the strains which will induce high stresses at the cladding/core interface.