Effects of Mg and Mn contents on the mechanical properties, corrosion behavior, and biocompatibility of biomedical zinc alloys

Zinc-based alloys are promising biodegradable implant materials, but their mechanical, corrosion, and biological properties require coordinated optimization. Here, Zn-Mg-Mn alloys with varying Mg and Mn contents were fabricated by powder metallurgy and evaluated for microstructure, mechanical properties, corrosion, wear, and biological performance. Zn-2.5 Mg-3.5Mn achieved the highest compressive yield strength (360 MPa) in the Zn-2.5 Mg-xMn series. Increasing Mn from 0 to 3.5 wt% raised hardness from 85 to 105 HV, while high-alloy-content specimens showed over 50 % lower wear rates. Among the ternary alloys, Zn-2.5 Mg-1Mn had the lowest electrochemical equivalent corrosion rate from short-term potentiodynamic polarization (0.375 mm/y). All alloys exhibited grade 0 cytotoxicity and hemolysis below 5 %. Zn-2.5 Mg-1Mn supported relatively high osteoblast viability and showed lower absolute BSA and fibrinogen adsorption, although cell adhesion and spreading were limited. Short-term subcutaneous implantation in mice caused mild early inflammation, followed by tissue repair and remodeling by day 7, without extensive ulceration or necrosis. Overall, Zn-2.5 Mg-1Mn provided a favorable balance of mechanical properties, corrosion resistance, in vitro biocompatibility, and short-term tissue response, supporting its potential as a biodegradable implant material.