组织和性能的影响
(北京有色金属研究总院 有色金属材料制备加工国家重点实验室， 北京 100088)
摘 要: 对Mg-5.0Y-7.0Gd-1.3Nd-0.5Zr(EW75M)合金在不同条件下挤压变形后的组织和性能进行测试。结果表明：随着挤压比的增大，合金的强度和塑性均大幅度提高，当挤压比增大到20以后，晶粒细化对合金的强化效果趋于稳定；当挤压筒温度由400 ℃升高到450 ℃时，合金强度和伸长率的降幅均在5%以内，挤压筒温度在400 ℃~ 450 ℃变化时对合金挤压变形后的性能影响较小；将合金均匀化处理(535 ℃、24 h)后直接进行挤压变形(挤压比20，挤压筒温度400 ℃，挤压速度1~2 m/min)，其极限抗拉强度、屈服强度和伸长率分别达到335 MPa、240 MPa和16.5%。
关键字: 镁合金；挤压比；挤压筒温度；微观组织；力学性能
（State Key Laboratory for Fabrication and Processing of Nonferrous Metals,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:The microstructures and mechanical properties of Mg-5.0Y-7.0Gd-1.3Nd-0.5Zr (EW75M) alloys extruded under different conditions were tested. The results indicate that both the strength and plasticity are improved with increasing extrusion ratio. When extrusion ratio is more than 20, the effect of grain refinement on strengthening has little improvement. When the extrusion tube temperature increases from 400 ℃ to 450 ℃, the average grain size has little increase, and both strength and elongation are decreased by less than 5%. After being hot treated at 535 ℃ for 24 h，EW75M alloy is directly extruded under conditions of extrusion ratio of 20, extrusion tube temperature of 400 ℃ and extrusion speed of 1−2 m/min. After being extruded, the ultimate tensile strength，yield strength and elongation of EW75M reach 335 MPa, 240 MPa and 16.5%, respectively.
Key words: magnesium alloy; extrusion ratio; extrusion tube temperature; microstructure; mechanical property
