In-situ synthesis of Mg-based bulk metallic glass matrix composites with primary α-Mg phases

●Our study presents in-situ synthesis and mechanical properties of Mg-based BMGMCs.●Mg-rich MgCuZnGd alloys with α-Mg 2nd phases are successfully designed via CALPHAD.●An in-situ Mg-based BMGMC with 2 mm diameter is prepared in Mg77Cu12Zn5Gd6 alloy.●α-Mg phases in BMG improve the plasticity due to formation of multiple shear bands.●Mg-rich BMGMCs in this study are promising for lightweight structural applications.