Study on the microstructural evolution and performance enhancement of Mg‐1Mn‐2Zn alloy via hot extrusion and laser surface remelting

This study examines the effects of hot extrusion and laser surface remelting on the microstructure, tribological behavior, and corrosion resistance of heat‐treated Mg‐1Mn‐2Zn alloy (composition: Mg as the matrix, 1 wt.% Mn, and 2 wt.% Zn). X‐ray diffraction (XRD) and electron backscatter diffraction (EBSD) analyses confirmed that both treatments significantly refined the grain structure. The average grain size decreased from 68.89 μm in the heat‐treated alloy to 6.51 μm after extrusion and 11.94 μm after laser surface remelting, accompanied by an increase in dislocation density. Tribological tests revealed that the treated specimens exhibited lower friction coefficients, smoother wear surfaces, and narrower wear pits than the heat‐treated specimen, demonstrating enhanced wear resistance. Electrochemical measurements further showed a substantial reduction in corrosion rate, from 5.15 mm/a in the heat‐treated alloy to 3.66 mm/a in the extruded alloy and 0.78 mm/a in the laser‐remelted alloy, indicating significantly improved corrosion resistance. Overall, these results suggest that hot extrusion and laser surface remelting are effective strategies to optimize the performance of medical magnesium alloys, offering promising potential for orthopedic implants and related medical devices.