Stability of dislocation loops near a free surface

Abstract

The effect of surface forces on the stability of edge dislocation loops, b=(1/2) [101], in MgO thin foils has been studied using transmission electron microscopy. The circular loops lying within a critical distance from the surfaces slip out without appreciable rotation. The critical distance in {100} foils, where the glide cylinders are at 45° to the foil surfaces, was found to increase with increasing loop size.