热挤压Mg-5Zn-0.6Zr-3Gd合金的显微组织与拉伸性能
Microstructures and Tensile Properties of Hot-Extruded Mg-5Zn-0.6Zr-3Gd Alloy
李锋，李宪明，车欣，陈立佳
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作者单位：沈阳工业大学
中文关键字：Mg-Zn-Zr-Gd合金；热挤压；热处理；显微组织；拉伸性能
英文关键字：Mg-Zn-Zr-Gd alloy; hot-extrusion; heat treatment; microstructure; tensile property
中文摘要：通过进行显微组织观察与室温拉伸性能测试，研究了热挤压Mg-5%Zn-0.6%Zr-3%Gd合金的显微组织及拉伸性能。结果表明，随着挤压比的增大，热挤压期间动态再结晶效应增强，合金的抗拉强度、屈服强度以及伸长率增大；经过时效处理后，合金中析出细小的第二相粒子，合金的屈服强度与伸长率的提高幅度较大，而抗拉强度略有提高。拉伸断口形貌观察与分析表明，挤压态和热处理态Mg-5%Zn-0.6%Zr-3%Gd合金的断裂方式都是脆性和韧性混合断裂，前者以脆性断裂为主，后者以韧性断裂为主。
英文摘要：Through performing both microstructural observations and tensile tests at room temperature, the microstructures and mechanical properties of hot-extruded Mg-5%Zn-0.6%Zr-3%Gd alloy were investigated. The results show that with increasing the extrusion ratio, the effect of dynamic recrystallization gets enhanced during hot-extrusion, and the ultimate tensile strength, yield strength and elongation of the alloy are improved. After aging treatment, the fine second phase particles precipitate in the alloy. The elongation and yield strength of the alloy are significantly improved, while the ultimate tensile strength gets slightly raised. The observations on the morphology of tensile fracture surfaces reveal that the fracture ways for as-extruded and aged Mg-5%Zn-0.6%Zr-3%Gd alloys are the mixed brittle and ductile rupture. For as-extruded alloy, the brittle fracture is main rupture mode, and for the aged alloy, the ductile fracture is main failure mode.