Climb kinetics of dislocation loops in aluminium

Abstract

The climb kinetics of dislocation loops in thin foils in terms of either the emission of vacancies from the loop or the diffusion of vacancies to the surface has been critically examined. Although both mechanisms give similar rate equations, predictions can be made which allow the rate controlling process to be determined experimentally. The annealing behaviour of faulted and prismatic loops in quenched aluminium has been studied using quantitative electron microscopy techniques and shown to support a theory based on vacancy diffusion. Hence by comparing the annealing rates of faulted loops with those of prismatic loops as a function of temperature the stacking-fault energy of aluminium has been determined to be 135±20 ergs/cm². This value is shown to be consistent with the physical properties of aluminium in relation to other metals.