固溶时效工艺对2297铝锂合金微观组织和力学性能的影响

摘要

通过扫描电镜(SEM)、透射电镜(TEM)和拉伸性能测试等方法系统研究固溶和时效工艺对2297铝锂合金组织和性能的影响.结果表明:实验合金较为适宜的固溶制度为((535±5)℃,1.5 h),基体中的第二相得到比较充分的溶解,同时抑制再结晶晶粒长大.T6态的主要强化相为T1相和 θ′相,T8态的主要强化相为T1相,时效前的预变形可以促进T1相的形成,提高合金的强度峰值,缩短合金达到峰值的时间,160℃时效后,未经预变形的合金的强度峰值为392 MPa,到峰时间为48 h,变形量为7%时,合金的强度峰值最高,达到482 MPa,到峰时间为23 h.%The effects of solid solution and aging process on structure and properties of 2297 Al-Li alloy were investigated by SEM, TEM and tensile tests systematically. The results show that the optimum solution treatment is determined as ((535±5) ℃, 1.5 h), and in this case, second phases can be more fully dissolved in the Al matrix and the sizes of recrystallized grains are moderate. The dominant strengthening phases during T6 are T1 phase and θ′ phase. Pre-deforming before aging can promote the nucleation of T1 phase, enhance the peak-aged strength and shorten the time to reach peak. The peak strength of the alloy under T6 state at 160 ℃ is 392 MPa after 48 h. The peak strength of the alloy at 7% pre-deformation is the highest strength which can reach 482 MPa after 23 h.