(1. 北京科技大学 材料科学与工程学院，北京 100083；
2. 机械科学研究总院 先进制造技术研究中心，北京 100083；
3. 北京有色金属研究总院，北京100088)
摘 要: 在保护气氛中采用喷射成形制备技术制备了形状完整的AZ91镁合金沉积圆柱坯。对沉积坯进行显微组织分析，结果表明：喷射沉积AZ91镁合金具有均匀、细小的等轴晶组织，平均晶粒尺寸约17 μm，有效地改善了离异共晶β-Mg17Al12相在晶界的偏析；挤压变形过程引发的动态再结晶使喷射成形AZ91镁合金的组织进一步细化；经175 ℃时效时，析出相中多数为不连续析出，连续析出所占比例很小；后期阶段时效过程加快，长时间时效未见片状及针状析出物球化现象。喷射成形AZ91 镁合金经挤压变形和T6处理后，抗拉强度和屈服强度分别达到435和360 MPa，伸长率为9.2%，实现了强度和韧性的同步大幅度提高。
关键字: AZ91镁合金；喷射成形；显微组织；力学性能
high strength AZ91 Mg alloy by spray forming technology
（1. School of Materials Science and Engineering, University of Science and Technology Beijing,
Beijing 100083, China;
2. Advance Manufacture Technology Center, China Academy of Machinery Science and Technology,
Beijing 100083, China;
3. Beijing General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:AZ91 magnesium preform with complete shape was prepared using spray forming technology under protective atmosphere. The microstructure analysis shows that AZ91 Mg alloy has homogeneous and equiaxial-grains structure, the average grain size is 17 μm. The segregation tendentiousness of divorce eutectic β-Mg17Al12 phase towards the grain boundary is greatly improved. The further grain refinement is attributed to the dynamic recrystallization during extrusion processing. When aging at 175 ℃, two kinds of precipitates exist which are the majority of lamellar discontinuous precipitates and a small amount of dispersive continuous precipitates. During the latter aging, β-Mg17Al12 phase precipitates quickly and no spheroidized lamellar is observed. The average tensile ultimate, yield strength and elongation of the sprayed AZ91 Mg alloy after extruded T6 treatment are 435 MPa, 360 MPa and 9.2%, respectively, at the room temperature, which indicates a better combination of toughness and strength.
Key words: AZ91 magnesium alloy; spray forming; microstructure; mechanical property
