Numerical study on the ductility improvement mechanism of dilute Mg-Ca alloys

LJ Liu and M Miyake and L Li and WL Jia and Y Shibutani, COMPUTATIONAL MATERIALS SCIENCE, 228, 112381 (2023).

DOI: 10.1016/j.commatsci.2023.112381

In recent years, magnesium (Mg) alloys have attracted extensive attention because of their potential use as alternatives to dense metals and Al alloys. Therefore, the low ductility of Mg alloys should be improved. Previous studies indicated that the addition of low concentrations of Ca improves the ductility of Mg alloys; however, the associated mechanisms are not well understood. The present numerical study demonstrates that the ratio of the critical resolved shear stresses associated with prismatic and basal < a > slip systems is significantly reduced (to a value of approximately 1) in a Mg-0.1 at.% Ca alloy. The incorporation of Ca was also found to harden the basal slip system while softening the prismatic slip system. The addition of Ca to Mg evidently provides a thermal-like effect that promotes the nucleation of kinks and enhances the dislocation motion. This effect is significantly more pronounced in the case of a prismatic slip system. The difference in importance of the thermal effect between the basal and prismatic slip systems and the Ca-promoted nucleation of kinks are the two main factors responsible for softening the prismatic slip system and improving the ductility of dilute Mg-Ca alloys.

Return to Publications page