MOLECULAR-DYNAMICS SIMULATIONS OF SPALLATION IN METALS AND ALLOYS

We report on the results of large-scale molecular dynamics simulations of the mechanical behavior of two-dimensional metallic systems. The s pecific impact phenomenon studied is that in which a flyer of mass M m oving with x-velocity upsilon impacts a target of mass 2M moving with x-velocity -upsilon/2. Simulations of such a spallation experiment hav e been performed for a generic metal, modelled with an embedded atom p otential and also for a Cu-Ni alloy system, modelled with truncated Le nnard-Jones potentials. Our simulations indicate cold-welding upon imp act, and shock wave generation, followed by rebound from the boundarie s. The alloy was less ductile than the generic metal and consequently the system came apart due to the cooperative effect of the reflected s hock waves. Copyright (C) 1998 Elsevier Science B.V.