Diffusion creep by dislocation climb in beryllium and Be-Cu single crystals

Abstract

High temperature creep of beryllium and Be-Cu alloy (10 wt pct Cu) single crystals com-pressed along the -c axis was shown to proceed by pure climb of -c dislocations (Burgers vector [0001]). Experimental results can be explained if we assume that -c dislocation loops grow in the basal planes. The activation energy for the climb of the -c dislocations is found to exceed the activation energy for self diffusion by 10 ±5 kcal/mole for both beryllium and Be-Cu. This leads us to think that thec dislocation climb rate is controlled by the processes of vacancy emission or absorption at jogs rather than by lattice diffusion.