(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 通过显微硬度测试、常规拉伸性能测试、扫描电镜和透射电镜等观察手段研究Cu含量对含Sc铝锂合金显微组织和力学性能的影响。结果表明:在Sc元素含量基本不变的情况下，Cu含量为4.2%(质量分数)的合金在均匀化过程中会形成W(AlCuSc)相，且该相在固溶时也不会完全溶解到α(Al)。在相同Sc含量条件下，随着α(Al)中Cu含量的下降，w(Cu)/w(Sc)变小，均匀化后形成的W相数量会明显降低，直至消失。由于W相对合金力学性能不利，其数量的减少可以增加合金中有效固溶Cu原子的数量，从而提高合金性能，W相的形成抑制合金中Al3(Sc,Zr)粒子的析出形成。
关键字: 铝锂合金；AlCuSc相；Cu含量；力学性能；显微组织
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effects of Cu content on the microstructure and mechanical properties of Al-Cu-Li-Sc alloys were investigated by microhardness test, tensile test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. The results indicate that the alloys with high Cu content will precipitate W(AlCuSc) phase during homogenization when the Sc content is same, and the W phase will not dissolve into the α(Al) at solution treatment. The amount of W phase will decrease with the reduction of Cu content while the Sc content is the same. Because of the deleterious effects of W phase on the mechanical properties, the content of Cu atoms in α(Al) improves, the precipitation of θ′ and T1 phases improve the mechanical properties after aging. The formation of Al(Sc,Zr) particles will be inhibited due to the existence of W phase.
Key words: Al-Li alloy; AlCuSc phase; Cu content; mechanical property; microstructure
