In Vitro Corrosion Behavior and Mechanical Property of Novel Mg–Sn–In–Ga Alloys for Orthopedic Applications

This study develops novel Mg–Sn–In–Ga alloys as potential implant materials for orthopedic applications. The corrosion behavior of the Mg–Sn–In–Ga alloys was studied through mass loss measurements, hydrogen evolution measurements, electrochemical analysis, and corrosion morphology observations. The results show that the corrosion rate of the Mg–1Sn–1In–1Ga alloy was only 0.10 ± 0.003 mm/y after immersion in Hank’s solution for 15 days. This outstanding corrosion resistance was associated with the protective effect of the corrosion products. The increase in the Sn and Ga element content led to the precipitation of a large amount of Mg₂Sn and Mg₅Ga₂, which had a dominant effect on the corrosion rate in the Mg–5Sn–1In–2Ga alloy. These precipitates increased the current density and detached from the alloy surface during the corrosion process. This can lead to a weakened protective effect of the corrosion layer, and thus generate localized corrosion and an increase in the corrosion rate. The strength of the Mg–5Sn–1In–2Ga alloy was enhanced due to fine-grain strengthening and precipitation strengthening. The ultimate tensile strength and yield strength of the Mg–5Sn–1In–2Ga alloy were ~ 309 MPa and ~ 253 MPa, respectively.