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本文系统地研究了8090Al-Li合金的微观结构与力学性能的关系。结果表明,合金性能的变化主要归因干δ′颗粒尺寸的变化和S′相的析出。δ′相容易析出并迅速长大,而S′相析出的孕育期较长,时效前冷变形可促进S′相析出。δ′相和S′相共同析出可改善合金强度和塑性,其最佳时效条件为190℃,20—30h。另外,在有平衡相析出的高角晶界容易形成无沉淀区,在峰值时效条件,其宽度可达200nm以上,但在亚晶界难以形成。
This paper systematically studied the microstructure and mechanical properties of 8090Al-Li alloy. The results show that the variation of the properties of the alloy is mainly attributed to the variation of dry δ ’grain size and the precipitation of S’ phase. δ ’is easily precipitated and grows rapidly, while the S’ phase precipitates longer incubation period, cold deformation before aging can promote the S ’phase precipitation. The coexistence of δ ’phase and S’ phase can improve the strength and ductility of alloy. The optimum aging conditions are 190 ℃, 20-30h. In addition, a precipitate-free zone is easily formed in a high-angle grain boundary precipitated in the equilibrium phase. Under peak aging conditions, the width is up to 200 nm or more, but is hard to form in the sub-grain boundary.