The deformation behaviour of bimodal sized Al2O3/Al nanocomposites were investigated by hot compression tests conducted in the temperature range 350–500°C and strain rates of 0.001, 0.01 and 0.1 s–1. The dynamic recrystallisation behaviour of the nanocomposites strongly depended on the forming parameters. The bimodal sized Al2O3 particles played a crucial role in the recrystallised microstructure. The addition of bimodal sized Al2O3 particles led to a significant increase of activation energy of plastic deformation, corroborating the enhanced resistance of the nanocomposite to hot deformation. This was also reflected by the increased compressive yield strength in the nanocomposite due to both dislocation strengthening caused by n‐Al2O3 and preventing the grain growth due to the presence of μ‐Al2O3 at grain boundaries. It was found that with the decrease of Z values, local strain induced by deformation was released and the grain size of aluminium matrix gradually increased, indicating that the main softening mechanism of the bimodal sized Al2O3/Al nanocomposites was dynamic recrystallisation (DRX). The lower the Z value was, the easier the DRX occurred. The highly beneficial role of the bimodal sized Al2O3 reinforcement in improving the high‐temperature performance of aluminium matrix nanocomposite was discussed.

中文翻译：

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放电等离子烧结制备双峰尺寸Al 2 O 3 /Al纳米复合材料的热变形行为

通过在 350-500°C 的温度范围和 0.001、0.01 和 0.1 s-1 的应变速率下进行的热压缩试验，研究了双峰尺寸的 Al2O3/Al 纳米复合材料的变形行为。纳米复合材料的动态再结晶行为很大程度上取决于成形参数。双峰尺寸的 Al2O3 颗粒在再结晶微观结构中起着至关重要的作用。添加双峰尺寸的 Al2O3 颗粒导致塑性变形活化能显着增加，证实了纳米复合材料对热变形的抵抗力增强。这也反映在纳米复合材料的压缩屈服强度增加上，这是由于 n-Al2O3 引起的位错强化和由于晶粒边界处存在 μ-Al2O3 而阻止晶粒生长。结果表明，随着Z值的减小，变形引起的局部应变得到释放，铝基体晶粒尺寸逐渐增大，表明双峰尺寸Al2O3/Al纳米复合材料的主要软化机制是动态再结晶（DRX）。Z 值越低，DRX 越容易发生。讨论了双峰尺寸的 Al2O3 增强材料在提高铝基纳米复合材料的高温性能方面的非常有益的作用。