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研究了Ce添加量分别为0.09%及0.23%的Al-4.15Cu-1.25Li-X高强铝锂合金薄板T6态时效(175℃时效)及T8态时效(5%冷轧预变形+155℃时效)时的微观组织和拉伸性能。结果表明,相比T6态时效,T8态时效时铝锂合金强度及伸长率均有所提高。T8态时效时,含0.23%Ce的铝锂合金强度及伸长率均低于Ce含量为0.09%的铝锂合金。Ce含量增加未改变铝锂合金中时效析出相的种类,主要强化相仍为T1相(Al_2CuLi)及θ’相(Al_2Cu),但其数量减少。微量Ce的添加可形成含Ce且富Cu的Al_8Cu_4Ce相粒子,这些粒子在均匀化及固溶处理时均难以完全溶解。Ce含量增加,导致固溶基体中Cu含量降低,时效时含Cu析出相T1相及θ’相含量减少,铝锂合金强度降低。
Al-4.15Cu-1.25Li-X high strength Al-Li alloy sheets with Ce addition of 0.09% and 0.23%, respectively, were tested for T6 aging (175 ℃ aging) and T8 aging (5% cold rolling pre-deformation + 155 ℃ aging ) When the microstructure and tensile properties. The results show that the strength and elongation of Al-Li alloys are improved when aging at T8 compared with aging at T6. T8 aging, the 0.23% Ce aluminum lithium alloy strength and elongation are lower than the Ce content of 0.09% of the aluminum-lithium alloy. The increase of Ce content did not change the types of precipitates in the Al-Li alloy. The main strengthening phases were still T1 phase (Al2CuLi) and θ ’phase (Al2Cu), but the number decreased. The addition of trace Ce can form Ce-rich Cu-rich Al_8Cu_4Ce phase particles, which are difficult to dissolve completely in homogenization and solution treatment. The content of Ce increases, which leads to the decrease of Cu content in solution matrix. The content of T1 phase and θ ’phase in Cu precipitation phase decreases and the strength of Al-Li alloy decreases.