ABSTRACT SiC/Al-4.5Cu and SiO2/Al-4.5Cu nanocomposites were fabricated by semi-solid stirring combined with ultrasonic cavitation and their hot-tearing resistance during casting investigated. The hot-tearing susceptibilities of Al-4.5Cu alloy and its nanocomposites were studied using a constrained rod casting steel mould. The results showed that the extent of hot tearing in the Al-4.5Cu alloys is greatly reduced by the addition of 1 wt% SiC or 1 wt% SiO2 nanoparticles. Microstructural analysis suggested that SiC and SiO2 nanocomposites refined the θ-Al2Cu phases and α-Al dendrites and lead to discontinuous Al2Cu phases along the grain boundaries in the Al-4.5Cu alloys during solidification, which leads to an enhancement on the hot-tearing resistance of Al-4.5Cu to a considerable degree. Moreover, SiO2 nanoparticles have a remarkable effect on the microstructure refinement of the Al-4.5Cu alloys.

中文翻译：

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半固态搅拌结合超声空化制备Al-4.5Cu纳米复合材料的热撕裂敏感性

摘要 采用半固态搅拌结合超声空化法制备了 SiC/Al-4.5Cu 和 SiO2/Al-4.5Cu 纳米复合材料，并研究了它们在铸造过程中的抗热撕裂性。使用约束棒铸钢模具研究了Al-4.5Cu合金及其纳米复合材料的热撕裂敏感性。结果表明，Al-4.5Cu 合金的热撕裂程度通过添加 1 wt% SiC 或 1 wt% SiO2 纳米颗粒大大降低。微观结构分析表明，SiC和SiO2纳米复合材料细化了θ-Al2Cu相和α-Al枝晶，导致Al-4.5Cu合金在凝固过程中沿晶界形成不连续的Al2Cu相，从而提高了抗热撕裂性Al-4.5Cu 在相当程度上。而且，