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测量了２０２４Ａｌ及其复合材料超塑变形到不同应变量时的正电子寿命谱，讨论了缺陷数量随应变量的变化规律及缺陷类型的相互转化规律 同时也讨论了铝合金及其复合材料超塑变形过程中空洞形核机制、控制空洞长大的因素及微观缺陷对超塑性能的影响结果表明：２０２４Ａｌ合金中的缺陷数量先增加，当延伸率达到８０％后显著降低；变形过程中晶格缺陷从变形初期的空位（团）对或位错转变为变形后期的单空位或位错，并且空洞的尺寸也在随变形量在变化复合材料中的缺陷数量是先缓慢增加，延伸率超过８０％后急增，增到一定程度后缺陷数量基本不变；变形过程中晶格缺陷从变形初期的单空位或位错转变为变形后期的空位对（团）或位错，而空洞的尺寸变化不大２０２４Ａｌ合金的空洞形核主要通过空位集聚，空洞不断吸收沿晶界扩散来的空位而迅速长大，最终这些大空洞在垂直于拉伸方向连接导致材料的破坏；复合材料主要是通过位错在ＳｉＣ／Ａｌ界面塞积引起的高应力集中致使界面开裂，形成微空洞，空洞的长大受周围材料的塑变控制，随延伸率的增大，ＳｉＣ与基体逐步脱粘形成一个个独立空洞的累积损伤导致材料突然断裂
The positron lifetime spectra of 2024Al and its composites at different strain levels were measured. The variation rules of the number of defects and the mutual transformation rules of the defect types were discussed. The superplasticity of aluminum alloy and its composites The results show that the number of defects in 2024Al alloy first increases, and then decreases significantly when the elongation reaches 80%. The deformation of the lattice Defects change from vacancies or dislocations at the initial stage of deformation to single vacancies or dislocations at the late stage of deformation, and the size of the cavities increases with the amount of deformation. The number of defects in the composite material firstly increases slowly, and the elongation exceeds 80 The number of defects increased to a certain extent after the basic unchanged; lattice defects during the deformation process from the initial deformation of single vacancies or dislocations into the late deformation gap (cluster) or dislocation, and the size of the cavity changes Small 2024Al alloy hollow nuclei mainly through vacancies, voids continue to absorb along the grain boundary expansion To the vacancies and the rapid growth of these large holes in the final perpendicular to the tensile direction of the connection led to the destruction of materials; composite material mainly through dislocation in the SiC / Al interface plugging caused by high stress concentration caused the interface cracking, the formation of micro-cavities , The growth of the cavity is controlled by the plastic deformation of the surrounding material. With the increase of the elongation rate, the cumulative damage of SiC and the matrix gradually debonding to form independent voids leads to the sudden fracture of the material