The generation of dislocations in metals by low energy ion bombardment

Abstract

Thin foils of gold, copper and nickel were bombarded on one surface with a beam of 100 ev argon ions at normal incidence. Glissile and Frank-sessile dislocation loops and dislocation dipoles were formed close beneath the bombarded surface, and both the type of loop and their arrangement were found to depend critically on the crystallographic orientation of the surface. The results are interpreted in terms of the stability of different dislocation arrangements near free surfaces of differing orientation. The condition for the stability of both glissile and sessile loops in gold is that their Burgers vectors should lie within approximately 5° of the plane of the surface. Only glissile loops were observed in copper. Sessile loops were more numerous in nickel than in gold.