An insight into the mechanism of SFT formation near 1/2 ‹110› edge dislocations in aluminum exposed to irradiation

Abstract

Recently molecular dynamics (MD) simulations have been carried out to study primary damage formation in the vicinity of 1/2 (110) screw and edge dislocations in aluminum [1, 2]. A few different interaction mechanisms of collision cascades with dislocations were detected. In particular, dislocation climb accompanied by the formation of stacking fault tetrahedra (SFT) near the dislocation line was observed. In order to clarify the peculiarities of SFT formation, normal strain in the dislocation core was reconstructed in a defect-free aluminum crystal and MD simulations of displacement cascades were conducted there under different temperatures. It has been found that tension/compression and the elevated temperature are the necessary but not sufficient conditions to form SFTs in aluminum. A vacancy supersaturation is required as well. In the vicinity of an edge dislocation in aluminum it is created due to absorption of displaced atoms by the dislocation core.