Pyramidal II to basal transformation of 'c plus a' edge dislocations in Mg-Y alloys

R Ahmad and ZX Wu and S Groh and WA Curtin, SCRIPTA MATERIALIA, 155, 114-118 (2018).

DOI: 10.1016/j.scriptamat.2018.06.026

Transitions of pyramidal 'c + a' dislocations to sessile structures contribute to poor ductility in pure Mg. Mg-3 wt% Rare Earth (RE) alloys have good ductility, possibly due to 'c + a' dislocation stabilization upon addition of RE solutes. Here, 'c + a' stability is investigated in a model Mg-3 at.%Y random solid solution alloy using molecular dynamics simulations. Favorable fluctuations of Y solutes lower all dislocation energies and have no appreciable effects on the transition mechanism, energy barrier, or time. Enhanced 'c + a' activity and improved ductility in Mg-3 wt%RE alloys are thus not likely associated with solute-stabilization of pyramidal 'c + a' dislocations. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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