Mg-9Gd-4Y-2Zn-0.5Zr镁合金的微观组织与性能研究

目的 研究挤压比对热挤压制备的Mg-9Gd-4Y-2Zn-0.5Zr(VW94)镁合金微观组织、拉伸性能和抗腐蚀性的影响，并揭示挤压比对组织和性能演变的影响机制。方法 用挤压比为16和35的热挤压工艺制备了Mg-9Gd-4Y-2Zn-0.5Zr(VW94)镁合金，通过光镜（OM）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）等手段表征并分析了不同挤压比下的微观组织，进一步通过拉伸测试和电化学测试评估合金的力学性能和腐蚀速率，并通过SEM表征断口形貌和腐蚀形貌，分析其断裂方式和腐蚀机制。结果 挤压比的大小并不会影响镁合金的相成分，镁合金主要由α-Mg基体及晶界处的LPSO相组成。当挤压比为16时，第二相数量更多，平均晶粒尺寸更小；当挤压比增大到35时，合金的再结晶程度更高，其晶粒尺寸分布更加均匀。性能表征结果发现，挤压比为16的VW94合金的力学性能更优，其抗拉强度及伸长率分别达到376.3MPa和13.3%，但是挤压比为35的VW94合金的耐腐蚀性能更好。结论 挤压比虽然不会影响相的种类，但是会影响第二相的含量和晶粒尺寸，从而进一步影响拉伸性能和腐蚀速率，因此可以通过优化挤压比协同...

Microstructure and Properties of Mg-9Gd-4Y-2Zn-0.5Zr Magnesium Alloy

The work aims to investigate the effect of extrusion ratio on the microstructure, tensile properties and corrosion resistance of Mg-9Gd-4Y-2Zn-0.5Zr (VW94) magnesium alloy prepared by hot extrusion technique, and reveal the effect mechanism of extrusion ratio on the evolution of microstructure and properties. Both hot extrusion processes with extrusion ratios of 16 and 35, respectively, were used to prepare VW94 magnesium alloy. The microstructures under different extrusion ratios were characterized and analyzed by optical microscopy (OM), X-ray diffractometer (XRD), scanning electron microscopy (SEM), etc. The mechanical properties and corrosion rates were further evaluated by tensile and electrochemical tests. Additionally, fracture modes and corrosion mechanisms were analyzed by SEM characterization of fracture profile and corrosion morphology. The extrusion ratio did not affect the phase composition of the magnesium alloy and the phase composition mainly consisted of the α-Mg matrix and the LPSO phase at the grain boundaries. The VW94 magnesium alloy with an extrusion ratio of 16 contained a higher content of second phases and a smaller average grain size. When the extrusion ratio increased to 35, the degree of recrystallization was higher and its grain size distribution was more uniform. The mechanical properties of VW94 alloy with extrusion ratio of 16 were better, and its tensile strength and elongation reached 376.3 MPa and 13.3%, respectively, but the corrosion resistance of VW94 alloy with extrusion ratio of 35 was better. Although the extrusion ratio does not change the phase type, it affects the content and grain size of the second phase, which further affects the tensile properties and corrosion rate. Therefore, the mechanical properties and corrosion resistance of the extruded VW94 alloy can be synergistically improved by optimizing the extrusion ratio.