(河南理工大学材料科学与工程学院,焦作 454010)
摘 要: 在Mg-6Zn合金中添加0.6%、1%和2% Ce(质量分数),联合往复挤压和低温正挤压细化Mg-Zn-Ce合金组织,利用X射线衍射、光学显微镜、扫描电镜和透射电镜分析合金中相组成和组织演化,测试合金的室温力学性能。结果表明:Mg-6Zn-0.6Ce合金中主要化合物为Mg4Zn7相,Mg-6Zn-1Ce和Mg-6Zn-2Ce合金中主要化合物为T-(MgZn)12Ce相。往复挤压合金经动态再结晶而细化,晶粒尺寸随Ce添加量增加而变小,分别为20.6 μm、16.5 μm和9.1 μm。低温正挤压时,合金再次发生动态再结晶而再次细化,晶粒尺寸分别为2.0 μm、8.6 μm和1.9 μm。Mg-6Zn-0.6Ce合金力学性能最佳,屈服强度、抗拉强度和伸长率分别为266.4 MPa、312.4 MPa和12.8%。合金的优良性能是由细晶强化、颗粒强化和固溶强化的共同作用造成的。
关键字: Mg-Zn-Ce;镁合金;往复挤压;挤压;力学性能
(School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454010, China)
Abstract:The microstructures of Mg-Zn-Ce alloys, which were prepared by adding 0.6%, 1% and 2% Ce (mass fraction) based on an Mg-6Zn alloy, were refined by combining reciprocating extrusion and low-temperature forward extrusion. The phase composition and microstructural evolution in alloys were analyzed by X-ray diffractometry, optical microscopy, scanning electron microscopy and transmission electron microscopy, the mechanical properties were tested at room temperature. The results show that major intermetallics in Mg-6Zn-0.6Ce alloy is Mg4Zn7 phase, the major intermetallics in Mg-6Zn-1Ce and Mg-6Zn-2Ce alloy is T-(MgZn)12Ce phase. The alloys are refined due to dynamic recrystallization after reciprocating extrusion, the grain size decreases with increasing Ce content, the grains sizes are 20.6 μm, 16.5 μm and 9.1 μm, respectively. The alloys are refined one more time due to dynamic recrystallization occurring once more during low-temperature forward extrusion, and the grain sizes are 2.0 μm, 8.6 μm and 1.9 μm, respectively. Mg-6Zn-0.6Ce alloys have the best mechanical properties, the yield strength, ultimate tensile strength and elongation are 266.4 MPa, 312.4 MPa and 12.8%, respectively. The excellent properties are attributed to the combination of fine grain strengthening, particle strengthening and solid solution strengthening.
Key words: Mg-Zn-Ce; magnesium alloy; reciprocating extrusion; extrusion; mechanical property