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镁合金在汽车、通讯电子和航空航天领域正得到日益广泛的应用,其中变形镁合金呈现出比铸造镁合金更优异的性能,但其强韧性仍有待于提高。利用光学显微镜(OM)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)分析了铸态和挤压态Mg-6.02Al-1.03Sm和Mg-5.95Al-1.01Sm-0.57Zn合金的组织和相组成,并测试了其室温和高温拉伸力学性能。结果表明,上述合金的铸态组织均由?-Mg基体、不连续网状?-Mg17Al12相和小块状化合物Al2Sm组成,后者合金中添加的Zn固溶于?-Mg基体和?-Mg17Al12相中;铸态合金呈现较优异的拉伸力学性能,如室温抗拉强度?b、屈服强度?0.2和伸长率?分别处于220~235 MPa、118~123 MPa和12.5~16.0%。经热挤压后,合金组织显著细化,再结晶晶粒的平均尺寸仅为12~14?m,Al2Sm相亦有所破碎;挤压态合金的拉伸力学性能显著提高:室温?b和?0.2分别提高至300~320 MPa和215~230 MPa,423 K时的高温?b、?0.2和?分别提高至205~215 MPa、161~166 MPa和42.0~44.0%。
Magnesium alloy is getting more and more widely used in the fields of automobile, telecommunication and aerospace. Among them, deformed magnesium alloy shows more excellent performance than cast magnesium alloy, but its toughness still needs to be improved. The microstructure of as-cast and as-extruded Mg-6.02Al-1.03Sm and Mg-5.95Al-1.01Sm-0.57Zn alloys were analyzed by OM, SEM and XRD. And phase composition, and tested its room temperature and high temperature tensile mechanical properties. The results show that the as-cast microstructure of the above alloys consists of Mg matrix, discontinuous network-Mg17Al12 phase and small block Al2Sm. The addition of Zn in the latter alloy dissolves in the Mg matrix and Mg17Al12 The as-cast alloys exhibit excellent tensile properties such as tensile strength at room temperature, yield strength of 0.2 and elongation at 220-235 MPa, 118-123 MPa and 12.5-16.0%, respectively. After hot extrusion, the microstructure of the alloy was refined remarkably, the average size of recrystallized grains was only 12 ~ 14μm, and the Al2Sm phase was also broken. The tensile mechanical properties of the as-extruded alloy significantly increased: ? 0.2 respectively to 300 ~ 320 MPa and 215 ~ 230 MPa, and the high temperature? B and? 0.2 and? At 423 K increased to 205-215 MPa, 161-166 MPa and 42.0-44.0% respectively.