中文摘要：

通过光学显微镜（OM）、扫描电子显微镜（SEM）、X射线衍射仪（XRD）和电子材料试验机研究了反向挤压Mg-6Sn合金的组织、织构和拉伸性能与挤压条件（挤压速度和初始坯料温度）间的依赖关系。研究结果表明：反向挤压Mg-6Sn合金的晶粒尺寸、再结晶体积分数和动态析出第二相体积分数在很大程度上取决于反向挤压参数,随着挤压速度和初始坯料温度的升高,合金的织构强度减弱。通过控制挤压速度和初始坯料温度,经高温挤压后的合金表现出最高的抗拉强度。对于商业AZ31镁合金而言,合金的强度随着挤压温度的升高而降低。本研究的Mg-6Sn合金经高温挤压后的抗拉强度和经低温挤压后的AZ31合金相当。上述研究结果表明Mg-6Sn合金是一种适合于高速度挤压的新型合金系。

英文摘要：

Dependence of microstructure, texture and tensile properties on working conditions（ram speed and initial billet temperature） in indirect extruded Mg-6wt%Sn alloys were investigated by optical microscope（OM）, scanning electronic microscope（SEM）, X-ray diffraction（XRD） and a standard universal testing machine. Results show that the grain size, the recrystallization fraction and the dynamic precipitate fraction of the alloys are greatly affected by the working conditions. Their texture intensities weaken as the ram speed and the initial billet temperature increase. Tested in the different working conditions, the ultimate tensile strengths of the Mg-6Sn alloys extruded at high working temperature（controlled by initial billet temperature and ram speed） are remarkably better than those at the medium and low temperatures. The tensile properties of the alloys extruded at the high working temperature are similar to those of a commercial AZ31 alloy extruded at the low temperature, showing the possibility of the development of high speed extruded Mg alloys based on Mg-6Sn alloy.