Enhanced age-hardening response of the Mg-Sm alloy via alloying with Cd

Compared to the basal precipitates, prismatic precipitates are considered more effective for age-hardening in magnesium alloys but happen in very limited alloy systems. Herein, we confirmed that very high density, nano sized prismatic Guinier-Preston zones (GP-zones) precipitated in an Mg-3Sm alloy with the addition of Cd, resulting in a significant enhancement in hardness. These two-dimensional GP-zones enriched with Sm and Cd have three variants of {1010}(alpha) habit planes, and fully coherent with the alpha-Mg matrix. This finding is expected to provide a practical guidance for designing and developing novel high-strength Mg rare-earth (RE) based alloys, and would put the way forwards understanding the clustering and stacking behaviors of solute atoms in hexagonal closed-packed (hcp) crystals.