采用挤压铸造法制成复合材料并热挤压成板材 ,然后对其进行了超塑拉伸实验。当拉伸温度为5 70℃ ,应变速率为 2 .0× 10 -3s-1时获得了 2 80 %的延伸率 ,用TEM观察了超塑变形过程中位错的变化分布规律。结果表明 ,位错的密度及分布与变形温度及应变速率有一定关系。在最佳变形条件下 ,变形初期位错主要集中在晶界处分布 ,随着变形量的加大 ,位错向晶粒中间扩展 ,并发现有层错及孪晶出现 ,这对协调变形具有一定作用。 The composite material was produced by squeeze casting and hot extruded into sheet, and then the superplastic tensile test was carried out on the sheet. When the stretching temperature was 5 70 ℃ and the strain rate was 2.0 × 10 -3 s-1, the elongation of 280% was obtained. The distribution of dislocation in superplastic deformation was observed by TEM. The results show that the density and distribution of dislocations have a certain relationship with deformation temperature and strain rate. Under the optimum deformation conditions, the dislocations are mainly distributed in the grain boundaries at the early stage of deformation. As the amount of deformation increases, the dislocations expand to the middle of the grains and faults and twins appear. Certain effect.