(华南理工大学 机械与汽车工程学院，广州 510640)
摘 要: 采用拉伸力学性能测试、宏观腐蚀、扫描电镜(SEM)、透射电镜(TEM)等，研究不同Zr含量对挤压铸造Al-5.0Cu-0.4Mn合金显微组织和力学性能的影响，并与重力铸造的合金的显微组织和力学性能进行对比分析。结果表明：针对铸态合金，无论是挤压铸造还是重力铸造，在Zr含量(质量分数)为0.25%时，合金获得最佳的抗拉强度、屈服强度和伸长率；而对于热处理态合金，当Zr含量从0增加到0.35%时，合金的抗拉强度和屈服强度都随着Zr含量的增加而增加，但伸长率在Zr含量为0.15%时达到最大值。挤压铸造可以显著改善不同Zr含量合金的伸长率，但对铸态合金伸长率的提升幅度明显优于热处理态合金的。Zr在铸态合金中的强化作用主要是细晶强化，而合金经T6热处理后，固溶强化以及Al3Zr粒子和θ?相的弥散强化是主要强化机制，挤压铸造可以显著改善Al3Zr粒子的弥散强化效果。
关键字: Al-Cu-Mn合金；挤压铸造；力学性能；显微组织
（School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:The effect of Zr on the microstructures and mechanical properties of Al-5.0Cu-0.4Mn alloy prepared by squeeze casting was studied by tensile test, macro corrosion test, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and took comparative analysis with the gravity cast alloy. The results show that the best tensile strength, yield strength and elongation are obtained for both the squeeze cast and gravity cast alloys in as-cast state when the Zr content is 0.25% (mass fraction). As for the heat-treated alloys, the tensile strength and yield strength increase when Zr content increases from 0 to 0.35%. However, the elongation reaches the maximum value when Zr content is 0.15%. Squeeze casting can significantly improve the elongation of the alloys with different Zr contents, but the improvement of the elongation of the as-cast alloys is significantly better than that of the heat-treated alloys. The dominant strengthening mechanism of Zr in the as-cast alloy is the grain refinement. However, the solid solution strengthening and dispersive strengthening of Al3Zr particles and q? phase are the main strengthening mechanisms in the alloy after T6 heat treatment. Squeeze casting can significantly improve the dispersion strengthening effect of Al3Zr particles.
Key words: Al-Cu-Mn alloy; squeeze casting; mechanical property; microstructure
