(广西科技大学 机械工程学院，柳州 545006)
摘 要: 采用光学金相显微镜、X射线衍射、拉伸试验、扫描电镜、透射电镜等技术，研究Cu含量对Al-Cu-Mg合金微观组织及力学性能的影响。结果表明：铸态Al-Cu-Mg合金中存在明显的树枝晶，沿晶界分布着大量块状S(Al2CuMg)和θ(Al2Cu)析出相。均匀化退火处理后，非平衡低熔点相基本熔入基体，晶间组织分布趋于均匀。大应变轧制变形后，3种Al-Cu-Mg合金中均得到典型的纤维状组织，合金中的第二相主要为S(Al2CuMg)相、θ(Al2Cu)相和T(Al20Cu2Mn3)相，沿晶界呈连续而均匀分布。经时效处理后，3种Al-Cu-Mg合金均表现出优异的综合力学性能，Cu含量为2%(质量分数)时，Al-Cu-Mg合金的抗拉强度、屈服强度和伸长率分别为507 MPa、430 MPa和10.3%；合金的力学性能随着Cu含量的增加呈递增趋势，当Cu含量为4.5%时，Al-Cu-Mg合金的抗拉强度、屈服强度和伸长率分别为644 MPa、547 MPa和10.5%。
关键字: Al-Cu-Mg合金；Cu含量；大应变轧制；显微组织；力学性能
（College of Mechanical Engineering, Guangxi University of Science and Technology, Liuzhou 545006）
Abstract:The effects of Cu content on microstructures and mechanical properties of Al-Cu-Mg alloy were investigated by optical microscopy, X-ray diffraction, tensile tester, scanning electron microscope and transmission electron microscope. The results show that there is obvious dendrite segregation in as-cast Al-Cu-Mg alloys, and a large number of massive S(Al2CuMg) and θ(Al2Cu) precipitates are distributed along the grain boundaries. After homogenization annealing treatment, the non-equilibrium low-melting phases are substantially dissolved into the matrix, and the intergranular structure distribution tends to be more uniform. After large strain rolling deformation, typical fibrous structures are obtained in the three kinds of Al-Cu-Mg alloys and the main secondary phases in the alloys are S(Al2CuMg), θ(Al2Cu) and T(Al20Cu2Mn3), which are continuous along the grain boundaries and evenly distributed. After aging treatment, all three kinds of Al-Cu-Mg alloys exhibit excellent comprehensive mechanical properties. When the Cu content is 2%(mass fraction), the tensile strength, yield strength and elongation are 507 MPa, 430 MPa and 10.3%, respectively. With the increase of Cu content, the mechanical properties of Al-Cu-Mg alloys show increasing trends, and the increase of Cu content has a significant effect on the mechanical properties of the alloy. When the Cu content is 4.5%, the tensile strength, yield strength, and the elongation of Al-Cu-Mg alloy are 644 MPa, 547 MPa, and 10.5%, respectively.
Key words: Al-Cu-Mg alloy; Cu content; large strain rolling; microstructure; mechanical property
