生物医用Mg-6Zn-xGd合金的挤压组织与腐蚀性能

Extruded Microstructures and Corrosion Properties of Biomedical Mg-6Zn-xGd Alloys

摘要:

通过光学显微镜和扫描电子显微镜研究了Mg-6Zn-xGd（x=0~4）合金的挤压态组织，测试了其拉伸力学性能和耐蚀性能。结果表明：随着Gd含量的增加，挤压态组织明显细化，平均晶粒尺寸从Mg-6Zn合金的12 um逐渐减至Mg-6Zn-3.41Gd合金的2 um；挤压态拉伸力学性能明显提高，抗拉强度σb和屈服强度σ0.2分别逐渐提高至Mg-6Zn-3.41Gd合金的350 MPa和325 MPa，延伸率δ先降低后提高，且均不低于10%。挤压态Mg-6Zn合金的腐蚀速率较慢，为典型的局部腐蚀；添加少量Gd（0.66%）后，合金的腐蚀速率稍增大，但腐蚀变得更均匀，朝着均匀腐蚀的方式发展；添加较多量Gd（1.66%和3.41%）后，合金的耐蚀性能急剧恶化。

Abstract:

Extruded microstructures of Mg-6Zn-xGd (x=0~4) alloys were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). Meanwhile, the tensile mechanical property and corrosion property were tested. The results show that extruded microstructure is refined obviously increasing the Gd content, where the average grain size decreases from 12 ?m for Mg-6Zn alloy to 2 ?m for Mg-6Zn-3.41Gd alloy. Extruded tensile mechanical property is enhanced obviously. Tensile strength σb and yield strength σ0.2 increase gradually from 295 MPa and 193 MPa for Mg-6Zn alloy to 350 MPa and 325 MPa for Mg-6Zn-3.41Gd alloy. Elongation δ first decreases, and then increases, which is not lower than 10%. Extruded Mg-6Zn alloy exhibits the slow corrosion rate with typical local corrosion. When a little Gd content (0.66%) is added, the corrosion rate increases slightly, however its corrosion becomes more uniform and changes to the uniform corrosion. When more Gd content (1.66% and 3.41%) is added, the corrosion resistance deteriorates sharply.