Numerical study of the athermal annihilation of edge-dislocation dipoles

Abstract

Abstract The stability against recombination of narrow edge-dislocation dipoles of the vacancy type is investigated in aluminium and copper by using atomistic-scale numerical simulation and phenomenological n-body potentials adapted to these metals. Stable and metastable equilibrium positions of edge dipole configurations have been considered and the influence of the dissociation width has been examined. The calculations show that, in aluminium, edge dipoles athermally annihilate at distances much larger than the Burgers vector length of perfect dislocations while, in copper, the dislocations forming the dipole recombine only when they are in close contact. These results are discussed in terms of surface energetics and in the framework of existing theoretical and experimental work.