Pii: S0749-6419(98)00026-6

ÐWe analyse the development of shear bands in axisymmetric, thermomechanical deformations of a circular tungsten heavy alloy (WHA) rod impacting at normal incidence a smooth rigid target. The rod's material is modeled either as a mixture of Fe±Ni±W particles interspread randomly among the W-particles or as a homogeneous alloy. For comparison purposes we also analyse deformations of a pure W and an Fe±Ni±W rod. It is found that shear bands, de®ned as narrow regions of rapid intense plastic deformation, form near the transition between the mushroomed region and the relatively undeformed portion of the rod, when its material is either a mixture of Fe±Ni±W and W particles or a homogeneous alloy but no such bands form in rods made of either W or Fe±Ni±W only. This could be due to the di€erent initial softening rates of the materials. # 1998 Elsevier Science Ltd. All rights reserved