INTERFACIAL EFFECTS DURING ION-BEAM PROCESSING OF METALS

Microstructural changes of surfaces and interfaces were investigated a t the atomic level by computer simulations. Molecular dynamics simulat ions were employed to examine the effects of self-atom bombardment of Au and Pt in the energy range 10-20 keV. It was observed that signific antly more damage and atomic mixing were produced near surfaces than i n corresponding recoil events in the bulk. Most damage is created by v iscous flow of liquid metal onto the surface, although in some cases, micro-explosions were observed. Interfacial mixing and roughening duri ng ion irradiation was simulated by Monte Carlo methods for multilayer ed structures of immiscible metals. It was observed that only few ball istic jumps relative to diffusion jumps are needed to roughen the inte rface, but that many more ballistic than diffusive jumps are needed to mis the layers.