挤压温度对Mg-6Zn-1Mn-4Sn-0.5Y镁合金组织和性能的影响（英文）

Effect of Extrusion Temperatures on Microstructures and Mechanical Properties of Mg-6Zn-1Mn-4Sn-0.5Y Alloy

通过光学显微镜(OM),X射线衍射(XRD),扫描电子显微镜(SEM),电子背散射衍射(EBSD)以及拉伸试验对360和420℃挤压的Mg-6Zn-1Mn-4Sn-0.5Y变形镁合金的组织和性能进行了研究。结果表明,合金铸态和时效态的相组成为α-Mg,Mn,Mg_7Zn_3,Mg_2Sn,和MgSnY相。挤压温度从360℃增加到420℃,动态再结晶完成,晶粒长大,合金的屈服强度、抗拉强度以及延伸率分别由259 MPa,350 MPa和18.3%降低至239 MPa,332 MPa和12.5%。理论计算和拉伸试验结果表明,细晶强化和固溶强化对合金屈服强度的增加产生决定性影响。

The microstructural evolution and the mechanical properties of Mg-6Zn-1Mn-4Sn-0.5Y wrought alloy extruded at 360 and 420 °C were investigated by optical microscopy（OM）, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, electron back scattered diffraction（EBSD） and tensile test. The results show that the phase compositions of as-cast and extruded alloys consist of α-Mg, Mn, Mg7Zn3, Mg2Sn, and MgSnY phases. As the extrusion temperature increases from 360 °C to 420 °C, dynamic recrystallization completes and grain growth occurs. The yield strength, the ultimate tensile strength and the elongation decrease from 259 MPa, 350 MPa and 18.3% to 239 MPa, 332 MPa and 12.5%, respectively. The theoretical calculations combined with the experimental results reveal that fine grain strengthening and solid solution strengthening play the dominating role in the enhancement of yield strength.