(1.哈尔滨理工大学 材料科学与工程学院, 哈尔滨 150080；
2. 东京大学 生产技术研究所, 东京 153-8505；
3.日本国立电气通信大学 机械工程系, 东京 182-8585)
摘 要: 利用固相合成方法在挤压比为11∶1的条件下, 将AZ91D镁合金屑分别在573、 623、 673和723 K时制备成试样, 对试样进行微观组织观察和力学性能测试。 结果表明：在573~673 K时, AZ91D镁合金的抗拉强度和延伸率随合成温度的升高而增大, 高于673 K时其抗拉强度和延伸率随合成温度的升高而降低, 在合成温度为673 K时, 其抗拉强度最高, 达到384.4 MPa； 在热挤出过程中氧化层被均匀弥散在组织中且发生动态再结晶, 使固相合成AZ91D镁合金的力学性能与铸态和用铸锭热挤出制备的镁合金相比明显提高, 在合成温度为673 K时, 其延伸率为5.8%, 比铸态增加152%； AZ91D镁合金屑在挤出过程中不能完全结合且出现较多的微裂纹, 使其延伸率与铸锭热挤出制备的AZ91D镁合金相比低44%。
关键字: AZ91D镁合金； 固相合成； 热挤出； 力学性能
AZ91D magnesium alloy by solid-state recycling
（1. School of Materials Science and Engineering,
Harbin University of Science and Technology, Harbin 150080, China;
2. Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan;
3. Mechanical Department, University of Electro-Communications,
Tokyo 182-8585, Japan）
Abstract: AZ91D magnesium alloy was prepared by hot extrusion of machined chips at 573, 623, 673 and 723 K with an extrusion ratio of 11∶1, subsequently its microstructure and mechanical properties were investigated. The results indicate that the ultimate tensile strength and elongation of AZ91D magnesium alloys increase with the elevation of preparation temperature at 573-673 K, and decrease with the elevation of preparation temperature above 673 K, and its ultimate tensile strength is the best at 673 K and can reach 384.4 MPa. Compared with the as-cast specimens and the extruded specimens from cast ingot, the mechanical properties of the AZ91D magnesium alloy improve evidently because the oxide layers are dispersed in the structure and the dynamic recrystallization happens in the extrusion process. When the preparation temperature is 673 K, the elongation is 5.8%, and it is 152% higher than that of the as-cast specimens. The AZ91D magnesium alloy machined chips can't be connected completely and a lot of cracks appear during the extrusion process. Compared with the extruded specimens from cast ingot at 673 K, the elongation is 44% lower.
Key words: AZ91D magnesium alloy; solid-state recycling; hot extrusion; mechanical properties
