Orientation-dependent defect accommodation and temperature-dependent strengthening in nanocrystalline magnesium: a molecular dynamics study

This molecular dynamics study decouples the orientation-dependent cryogenic strengthening of nanocrystalline magnesium across temperatures from 100 K to 300 K. Results reveal an orientation-sensitive cryogenic strengthening effect. At 100 K, the hard-oriented model achieved the highest absolute strength of approximately 1.9 GPa via athermal {10-12} tensile twinning. Conversely, the soft-oriented model exhibited the greatest relative temperature sensitivity with a 21% increment governed by thermally activated basal slip. In comparison, the random-oriented model demonstrated the lowest sensitivity of 13% due to a synergistic slip-twinning interplay. These atomic-scale insights provide a mechanistic framework for tailoring cryogenic magnesium alloys through orientation control.