Exploring the transfer of plasticity across Laves phase interfaces in a dual phase magnesium alloy

The mechanical behaviour of Mg-Al alloys can be largely improved by the formation of an intermetallic Laves phase skeleton, in particular the creep strength. Recent nanomechanical studies revealed plasticity by dislocation glide in the (Mg,Al)(2)Ca Laves phase, even at room temperature. As strengthening skeleton, this phase remains, however, brittle at low temperature. In this work, we present experimental evidence of slip transfer from the Mg matrix to the (Mg,Al)(2)Ca skeleton at room temperature and explore associated mechanisms by means of atomistic simulations. We identify two possible mechanisms for transferring Mg basal slip into Laves phases depending on the crystallographic orientation: a direct and an indirect slip transfer triggered by full and partial dislocations, respectively. Our experimental and numerical observations also highlight the importance of interfacial sliding that can prevent the transfer of the plasticity from one phase to the other. (C) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Automated summary

The mechanical behavior of Mg-Al alloys can be greatly improved by the formation of an intermetallic Laves phase skeleton, particularly in terms of creep strength. Recent studies have shown plasticity by dislocation glide in the (Mg,Al)(2)Ca Laves phase even at room temperature. Experimental evidence and atomistic simulations have identified two mechanisms for transferring Mg basal slip into Laves phases, emphasizing the importance of interfacial sliding in preventing plasticity transfer between phases.