Alloying effects on the plasticity of magnesium: comprehensive analysis of influences of all five slip systems.

Low plasticity has been a major issue for the application of Mg alloys. Here, based on the generalized stacking fault energy curves and Arrhenius equation, we systematically study alloying effects on the stacking fault energies and the activation probability of basal and non-basal 〈a〉, and pyramidal 〈c  +  a〉 slip systems in twenty-one Mg alloys. Our results reveal that activation of 〈c  +  a〉 slip systems on pyramidal II plane can significantly improve the plasticity. For example, Ca is found to promote the activation probability of this slip system by one order of magnitude and dramatically improve the plasticity of Mg.