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Molecular dynamic simulation of edge dislocation-void interaction in pure Al and Al-Mg alloy

Research paper by M. Bahramyan, R. Taherzadeh Mousavian, D. Brabazon

Indexed on: 02 Aug '16Published on: 30 Jul '16Published in: Materials Science and Engineering: A



Abstract

In this study, the interaction of edge dislocations with nano-scale voids was investigated for the face centered cubic (FCC) structure of pure aluminum and Al-Mg alloy. The effect of Mg solute atoms on the Peierls stress (required for dislocation motion) at different temperatures, and the critical resolved shear stress (CRSS) for dislocation-void interaction was investigated in this study. In addition, the influences of void diameter(1, 2 and 3 nm), inter-void distance (7.5 and 15 nm) in a void array, and of temperature (300 °K) on resolved shear stress were determined. It was found that substitutional Mg atoms was highly effective on improving the mechanical behavior of the Al lattice and on the type of dislocation-void interaction (simultaneous or separate passing of partial dislocations). In addition, it was obtained that no void-induced climbing occurred during the interactions for these systems. Higher void diameter and in particular lower inter-void spacing led to a considerable increase in the CRSS, while the latter changed the type of dislocation-void interaction. Finally, it was shown that Peierls stress was decreased for pure aluminum from 0 °K to 10 ° K, while different results were obtained for Al-Mg alloy that were discussed in detail.

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