Understanding on the role of rare earth elements in activation of 〈c+a〉 slip in magnesium: An atomistic approach

Abstract

The effect of Li addition on the slip behavior of Mg has been investigated using a molecular dynamics simulation. Based on a previous study on Mg–Y alloys concluding that a reduction of the anisotropy in critical resolved shear stress (CRSS) among difference slip systems activates the 〈c+a〉 slip, the effect of Li, an element known to improve the room temperature ductility of Mg is chosen as an alloying element to examine the robustness of the above-mentioned conclusion. It is found that Li increases the CRSS of the basal slip more than that of the non-basal slip, reducing the difference in the CRSS among different slip systems. The reduced anisotropy in CRSS is believed to activate the non-basal 〈c+a〉 slip and eventually improve ductility in Mg–Li alloys. This understanding can be further extended into an alloy design of more cost-effective Mg alloys with improved room temperature formability.