(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 通過顯微硬度測試、常規(guī)拉伸性能測試、掃描電鏡和透射電鏡等觀察手段研究Cu含量對含Sc鋁鋰合金顯微組織和力學(xué)性能的影響。結(jié)果表明:在Sc元素含量基本不變的情況下，Cu含量為4.2%(質(zhì)量分數(shù))的合金在均勻化過程中會形成W(AlCuSc)相，且該相在固溶時也不會完全溶解到α(Al)。在相同Sc含量條件下，隨著α(Al)中Cu含量的下降，w(Cu)/w(Sc)變小，均勻化后形成的W相數(shù)量會明顯降低，直至消失。由于W相對合金力學(xué)性能不利，其數(shù)量的減少可以增加合金中有效固溶Cu原子的數(shù)量，從而提高合金性能，W相的形成抑制合金中Al3(Sc,Zr)粒子的析出形成。
關(guān)鍵字: 鋁鋰合金；AlCuSc相；Cu含量；力學(xué)性能；顯微組織
（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
