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研究了铸态AZ80A镁合金汽车轮毂预制坯的超塑成形,通过实验验证了该合金超塑性成形的最佳工艺参数为:成形温度410℃、应变速率0.01 s-1;在选定成形参数的基础上制订了超塑成形工艺,等温挤压成形出合格的汽车轮毂预制坯试样;通过对轮毂预制坯成形前后的微观组织的对比分析发现,在预制坯成形过程中AZ80A镁合金发生了动态再结晶,形状不规则的粗大铸态晶粒通过挤压成形变成了晶粒细小的等轴晶,枝晶状的β相被破碎,沿轴向等轴晶呈带状分布,形成了纤维织构。通过试样检测发现,等温成形轮毂预制坯的综合力学性能良好,特别是轴向力学性能更为突出,这是因为成形后的晶粒细化和纤维织构形成。
The superplastic forming of the as-cast AZ80A magnesium alloy automobile wheel hub preform has been studied. The optimum technological parameters of the superplastic forming of the alloy AZ80A alloy have been verified by experiments: the forming temperature is 410 ℃ and the strain rate is 0.01 s-1. Based on the development of superplastic forming process, isothermal extrusion forming a qualified automobile hub preform samples; by analyzing the microstructure of the wheel hub preform before and after forming found that in the preform forming AZ80A magnesium alloy dynamic The recrystallized and irregularly shaped coarse as-cast grains are transformed into fine equiaxed grains by extrusion and the dendritic β phase is broken and distributed along the equiaxed grains in the axial direction to form fibers Texture. Through the test of the sample, it is found that the mechanical properties of isothermal formed hub preform are good, especially the axial mechanical properties are more prominent because of the grain refinement and fiber texture formation after forming.