HRTEM Characterization of an Age-Hardened Mg-Ca Binary Alloy

A Mg-2.8 mass% Ca binary alloy was subjected to a homogenization treatment. The three-dimensional morphology and coherency of the parallel to the {1 ⠁010}& alpha; columnar plane of the & alpha;-Mg matrix. The coarsening Mg2Ca precipitate retained coherency with the & alpha;-Mg matrix for aging time of 3 h, which corresponded to the peak-aged condition. Furthermore, during the coarsening process, misfit dislocations were introduced on the planar surface of the precipitates, and the coherent interface became a semi-coherent interface for aging time of 100 h, which corresponded to the over-aged condition. The Mg2Ca precipitates evolved from a hexagonal plate-like morphology to a rectangular morphology and then to a polygonal morphology during aging treatment at 423 K. [doi:10.2320/jinstmet.J2023002]