The effects of extrusion temperature on the microstructure and tensile properties of extruded AZ61 and AZ91 alloys are investigated by subjecting them to hot extrusion at 300 and 400 °C. Although the average grain size of the extruded AZ61 alloy slightly increases from 9.5 to 12.6 µm with increasing extrusion temperature, its resultant microstructural variation is insignificant. In contrast, the average grain size of the extruded AZ91 alloy significantly increases from 5.7 to 22.5 µm with increasing extrusion temperature, and the type of Mg₁₇Al₁₂ precipitates formed in it changes from fine dynamic precipitates with a spherical shape to coarse static precipitates with a lamellar structure. As the extrusion temperature increases, the tensile yield strength of the extruded AZ61 alloy increases from 183 to 197 MPa while that of the extruded AZ91 alloy decreases from 232 to 224 MPa. The tensile elongations of the extruded AZ61 and AZ91 alloys decrease with increasing extrusion temperature, but the degree of decrease is significant in the latter alloy. These different extrusion temperature dependences of the tensile properties of the extruded AZ61 and AZ91 alloys are discussed in terms of their microstructural characteristics, strengthening mechanisms, and crack initiation sites.

通过300和400℃热挤压，研究了挤压温度对挤压AZ61和AZ91合金显微组织和拉伸性能的影响。尽管随着挤压温度的升高，挤压AZ61合金的平均晶粒尺寸从9.5微米略微增加到12.6微米，但由此产生的微观结构变化并不显着。_{相比之下，随着挤压温度的升高，挤压AZ91合金的平均晶粒尺寸从5.7微米显着增加到22.5微米，并且Mg 17} Al ₁₂的类型其内部形成的析出物由球状的细小动态析出物转变为片状结构的粗大静态析出物。随着挤压温度的升高，挤压AZ61合金的拉伸屈服强度从183 MPa增加到197 MPa，而挤压AZ91合金的拉伸屈服强度从232 MPa下降到224 MPa。AZ61和AZ91合金的挤压伸长率随着挤压温度的升高而降低，但后者降低的程度显着。讨论了挤压 AZ61 和 AZ91 合金拉伸性能的不同挤压温度依赖性，包括微观结构特征、强化机制和裂纹萌生位点。