Pressure-driven Mn solubility enhancement in Zn alloy: Synergistic strengthening and reduced corrosion rate for biomedical application
摘要
Zn-Mn alloys are regarded as promising biodegradable metals for orthopedic applications owing to their moderate degradation rates and favorable osteogenic properties. However, the presence of a substantial number of second-phase particles in Zn-based alloys might induce severe localized degradation via micro-coupling corrosion, thereby compromising the mechanical integrity of the alloy during in vivo tissue regeneration. In this study, high-pressure solid solution (HPSS) treatment was conducted at 5 GPa and 380 °C for 1 h to fabricate Zn-0.5Mn alloys. Microstructural characterization revealed that the HPSS treatment facilitated the formation of a supersaturated solid solution by completely dissolving the ζ-MnZn13 phase into the α-Zn matrix. The resultant strengthening mechanisms, including supersaturated solid solution strengthening, grain-size strengthening, and dislocation strengthening, collectively enhanced the compressive yield strength (σcys) of the Zn-0.5Mn alloy to about 183.7 MPa, approximately three times that of the as-cast (AC) Zn-0.5Mn alloy. Moreover, compared with the AC alloy, the HPSS Zn-0.5Mn alloy exhibited uniform degradation behavior with a markedly reduced degradation rate.