(1. 河南科技大学 材料科学与工程学院，洛阳 471023；
2. 有色金属共性技术河南省协同创新中心，洛阳 471023；
3. 西南交通大学 材料科学与工程学院，成都 610031)
摘 要: 研究了Gd含量对挤压态Mg-0.5Zr-1.8Zn-xGd(0~2.5%，质量分数)生物镁合金组织及耐腐蚀性能的影响。结果表明：挤压比为7.7、挤压温度为350 ℃时，合金发生了完全动态再结晶，其晶粒尺寸随Gd含量的增加先减小，最后趋于稳定。合金中的第二相主要由颗粒状(Mg, Zn)3Gd相和Mg2Zn11相组成，其数量、尺寸及体积分数随Gd含量的增加逐渐增大，同时，纳米级棒状(Mg, Zn)3Gd相与合金基体具有半共格界面关系。Gd含量大于2.0%(质量分数)时，部分未溶第二相以弯曲线条状在合金基体中随机分布，其尺寸及数量随Gd含量的增加逐渐增大。合金的耐腐蚀性能随Gd含量的增加先增强后减弱，Gd含量为1.0%(质量分数)时，合金具有较好的耐腐蚀性能。
关键字: 镁合金；挤压；微观组织；耐腐蚀性能
（1. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, China;
2. Collaborative Innovation Center of Nonferrous Metals of Henan Province, Luoyang 471023, China;
3. College of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China）
Abstract:The effects of Gd content on the microstructure and corrosion resistance of the as-extruded Mg-0.5Zr-1.8Zn-xGd alloys (0-2.5%) was investigated. The results show that, when the extrusion ratio is 7.7 and the extrusion temperature is 350 ℃, the alloys have undergone complete dynamic recrystallization. The grain size decreases with the increase of Gd content and finally tends to be stable. The second phase in the alloy consists mainly of the granular (Mg, Zn)3Gd phase and the Mg2Zn11 phase, and volume of the second phase gradually increase with increasing Gd content. Meanwhile, the nano-scale granular (Mg, Zn)3Gd phase has a semi-congruent interfacial relationship with the alloy matrix. When Gd content is greater than 2.0%, a portion of the insoluble second phase is randomly distributed in the alloy matrix in the form of curved lines, and the volume and the amount gradually increase as Gd content increasing. The corrosion resistance of the alloy is enhanced and then weakened with the increase of Gd content, that the alloy has the best corrosion with a Gd content of 1.0%.
Key words: magnesium alloy; extrusion; microstructure; corrosion resistance
