TEMPERATURE-DEPENDENCE OF THE THRESHOLD ENERGY FOR ATOM DISPLACEMENTSIN CU

The threshold energy surface for permanent atom displacements in coppe r at 550 K is determined by observing the growth of interstitial-type dislocation loops during electron irradiation in a high-voltage electr on microscope. Comparison with the results of King et al. and Baily et al., obtained by measurements of the residual electrical resistivity, permits for the first time a detailed analysis of the variation of th e anisotropy of the threshold energy surface of a metal over a wide te mperature range. The mechanisms mainly responsible for the temperature dependence, which in f.c.c. metals is particularly pronounced for ene rgy transfers in [111] directions, are discussed in some detail.