(1. 北京宇航系统工程研究所，北京 100076;
2. 中南大学 材料科学与工程学院，长沙 410083)
摘 要: 以5.2 mm厚度2195-T8铝锂合金为对象，进行重固溶、4.5%预变形后不同温度(145C~160 ℃)的T8再时效处理，研究其力学性能与晶内显微组织演化。结果表明：重固溶处理后的晶粒形态与原始2195-T8态晶粒形态一样，仍然保持为拉长的带状晶粒组织。重固溶并经4.5%预变形后，再采用适当的温度和时间进行T8时效处理，2195铝锂合金可以回复到原始T8态的显微组织和力学性能，即2195铝锂合金采用重固溶-T8再时效处理不会明显损害其力学性能。2195铝锂合金的晶内时效析出相包括T1相(Al2CuLi)、δ′相(Al3Li)、θ′相(Al2Cu)及θ″相(Al2Cu)，其中优先析出相为T1相；较低温度及较短时间时效可形成较多δ′相和θ″相；随着时效时间延长，T1相生长，θ″相转化为θ′相并减少，δ′相消失；时效温度提高可促进该转变过程，加快铝锂合金的时效响应速度。
关键字: 铝锂合金；重固溶；再时效；显微组织；力学性能
（1. Beijing Institute of Aerospace Systems Engineering, Beijing 100076, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Based on 2195-T8 Al-Li alloy with 5.2 mm thickness, the mechanical properties and intragranular microstructural evolution during T8 (4.5% pre-deformation) re-aging at 145-160 ℃ after re-solution were investigated. The results show that the grain after re-solution still maintains as elongated pancake-like appearance, which is the same as that of original 2195-T8. The micro-structures and mechanical properties can recover to those of the original 2195-T8 Al-Li alloy through using appropriate T8 re-aging temperature and time. Re-solution and T8 re-aging treatment do not obviously damage 2195 Al-Li alloy mechanical property. The intragranular precipitates include T1(Al2CuLi), δ′(Al3Li), θ′(Al2Cu) and θ″(Al2Cu), among which the preferential precipitates are T1 phases. Re-aging at lower temperature or for shorter time, much more δ′ and θ″ precipitates are formed. With time extension, T1 precipitates grow, but θ″ precipitates are transformed to θ′ precipitates, and δ′ precipitates disappear. As re-aging temperature is elevated, the transformation process is accelerated, and the aging response is promoted.
Key words: Al-Li alloy; re-solution; re-aging; microstructure; mechanical property
