Significant enhancement of the age-hardening response in Mg-10Sn-3Al-1Zn alloy by Na microalloying

A trace addition of Na to the Mg-9.8Sn-3.0Al-0.5Zn (wt.%) (TAZ1031) alloy substantially enhances the peak-aged hardness from 53 to 99 HV at 200 °C, and to 109 HV at 160 °C, and accelerates the precipitation kinetics. Na clusters act as heterogeneous nucleation sites for lath-shaped Mg2Sn precipitates, thereby refining the precipitate microstructure.