Microstructure, mechanical property and corrosion behavior of biomedical Zn-Fe alloy prepared by low-temperature sintering

Zn is recognized as a novel orthopedic implant due to its excellent biocompatibility and favorable degradation behavior. Nevertheless, its poor strength and hardness fail to meet mechanical requirements of orthopedic implants. In this study, Fe with excellent mechanical properties was successfully alloyed with Zn at low temperature of 350 ℃ via rapid spark plasma sintering. Alloying Fe activated grain boundary pinning effect where pinning force at the grain boundary inhibited grain growth, and significantly refined grain. The grain refinement reduced stress concentration, and induced large resistance to dislocation and cracks growth, which improved mechanical properties of Zn-Fe alloys. Moreover, the formation of intermetallic FeZn13 phases contributed to precipitation strengthening. As a result, compression yield strength and hardness of Zn-Fe alloys were increased to 135.2 MPa and 64.6 Hv, respectively. Additionally, Zn-Fe alloys exhibited good biocompatibility to MG-63 cells in cytotoxicity assay. All these results demonstrated that Zn-Fe alloys were a great potential candidate as orthopedic implants.