▎ 摘　　要

Magnesium matrix composites reinforced with 0.3 wt.% graphene were fabricated by semi-solid isothermal treatment using various reheating conditions and hot extrusion. The microstructures of the hot-extruded AZ31/graphene composites were clearly refined, with the finest grain size (7.05 mu m) achieved after reheating at 610 degrees C for 30 min. Energy-dispersive x-ray spectroscopy analysis revealed that increasing the reheating temperature promotes diffusion of the solute elements and affects the mechanical properties of the composite. The optimal mechanical properties were achieved after reheating at 620 degrees C for 30 min, with a yield strength of 214.82 MPa and an ultimate tensile strength of 310.79 MPa. The significant improvement in the mechanical properties of the composite was mainly attributed to the refined grain size, uniformly redistributed solute elements, addition of graphene, and close interfacial bonding.