挤压态生物可降解镁合金Mg-2Zn-1Y-0.5Zr的显微组织、力学性能和腐蚀行为

Microstructure, Mechanical Properties and Corrosion Behavior of Biodegradable As-extruded Mg-2Zn-1Y-0.5Zr Alloys

摘要:

研究了挤压温度对挤压态Mg-2Zn-1Y-0.5Zr生物可降解镁合金动态再结晶、织构和拉伸性能的影响，基于显微组织和腐蚀形态阐述了挤压态合金在模拟体液中的腐蚀机理。结果表明，在440 ℃（E440）下挤压的合金出现双峰结构，具有粗大的未再结晶（unDRXed）晶粒和细小的再结晶（DRXed）晶粒。未再结晶区域的变形晶粒对织构强度的影响最大。460 ℃的挤压合金（E460）具有均匀的再结晶晶粒，晶粒细化后拉伸性能显著改善。同时，均匀的再结晶晶粒会弱化织构强度。E460的样品表现出最佳耐腐蚀性，腐蚀速率为0.669±0.017 mm·a^-1。

Abstract:

The effects of extrusion temperature on dynamic recrystallization, texture and tensile properties of biodegradable Mg-2Zn-1Y-0.5Zr alloys were studied, and the corrosion mechanisms of as-extruded alloys in SBF solution were elaborated. The results show that the extruded alloy at 440 ℃ (E440) has a bimodal structure with coarse unrecrystallized (unDRXed) grains and fine recrystallized (DRXed) grains. The deformed grains from unDRXed region make the greatest contribution to the texture strength. The extruded alloy at 460 ℃ (E460) has uniform DRXed grains, and its excellent tensile properties reveal a dominance of fine grain strengthening. Simultaneously, the uniform DRXed grains are good for the weakening of texture strength. The E460 sample exhibits the best corrosion resistance with a corrosion rate of 0.669 ± 0.017 mm·a^-1.