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采用脉冲电沉积技术制备不同大小Al2O3颗粒的Al2O3/Ni-Co纳米复合材料,研究其在不同应变速率和变形温度下的力学性能变化。结果表明,在应变速率为8.33×10-4s-1时,变形温度升高,材料的伸长率先增大后减小;应变速率为1.67×10-2s-1时,变形温度升高,材料的伸长率先减小后增大。断裂后材料表面未发现硫的偏析,但出现大量位错和孪晶。表明经超塑性变形后,复合材料内孪晶是晶界滑移的重要协调机制。
The Al2O3 / Ni-Co nanocomposites with different sizes of Al2O3 particles were prepared by pulsed electrodeposition, and their mechanical properties were studied under different strain rates and deformation temperatures. The results show that when the strain rate is 8.33 × 10-4s-1, the deformation temperature increases and the elongation of the material first increases and then decreases. When the strain rate is 1.67 × 10-2s-1, the deformation temperature increases. The elongation of the first decrease and then increase. Sulfur segregation was not observed on the surface of the material after fracture, but a large number of dislocations and twins appeared. It is shown that the twin in the composite is an important coordination mechanism of grain boundary slip after superplastic deformation.