In this paper, the effect of Y content on hot tearing properties of cast Al–Cu–Mg alloy was studied. The effect and mechanism of Y on hot tearing of cast Al–4.4Cu–1.5Mg–0.15Zr alloy were studied by analyzing the microstructure evolution, phase structure, solidification process and hot tearing sensitivity coefficient of the alloy with different Y additions, and determined the appropriate amount of Y element. The results showed that Y improves hot tearing resistance of Al–4.4Cu–1.5Mg–0.15Zr alloy by refining microstructure and reducing the solidification temperature range. The suitable amount of Y is 0.15 wt%. At this time, a certain amount of Al₆Cu₆Y low melting point phase is formed in the alloy, and the grain structure is the smallest, which significantly improves the hot tearing resistance of Al–4.4Cu–1.5Mg–0.15Zr alloy. The microstructure coarsening and hot tearing tendency increase with increasing Y content. The experimental results are basically consistent with the hot tearing sensitivity predicted by the Clyne–Davies model.

本文研究了Y含量对铸造Al-Cu-Mg合金热裂性能的影响。通过分析不同Y添加量合金的显微组织演变、相结构、凝固过程和热裂敏感性系数，研究了Y对铸造Al-4.4Cu-1.5Mg-0.15Zr合金热裂的影响和机理，并确定适量的Y元素。结果表明，Y通过细化组织和降低凝固温度范围提高了Al-4.4Cu-1.5Mg-0.15Zr合金的抗热撕裂性。Y的合适量为0.15wt％。此时，一定量的 Al ₆ Cu ₆合金中形成Y低熔点相，晶粒组织最小，显着提高了Al-4.4Cu-1.5Mg-0.15Zr合金的抗热裂性能。随着Y含量的增加，显微组织粗化和热裂倾向增加。实验结果与Clyne-Davies模型预测的热撕裂敏感性基本一致。