不同时效制度对铝锂合金力学性能与微观组织的影响  

Effects of different aging treatments on properties and microstructure of Al-Li alloy

作　　者：马晓光 曾元松 蔡彦岑 韩宝帅 徐严谨 刘丹阳[2] MA Xiao-guang;ZENG Yuan-song;CAI Yan-cen;HAN Bao-shuai;XU Yan-jin;LIU Dan-yang(Department of Materials Application Research,AVIC Manufacturing Technology Institute,Beijing 100024,China;School of Materials Science and Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中国航空制造技术研究院材料应用研究部,北京100024 [2]中南大学材料科学与工程学院,长沙410083

出　　处：《中国有色金属学报》2023年第9期2787-2800,共14页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51971206);航空工业制造院青年基金资助项目(KS912024144)。

摘　　要：本文采用TEM、SEM、EBSD和室温拉伸测试等方法,研究了时效温度及预拉伸过程对喷射成形2195铝锂合金挤压棒组织性能的影响规律。结果表明:当时效温度低于145℃时,2195铝锂合金T6状态下基体微观组织中主要形成GP区+θ″/θ′相,而T8状态下基体微观组织中主要形成T1+θ′相,且T8状态下合金的晶界无析出带宽度相对T6状态显著降低。当时效温度增加至155℃时,2195铝锂合金T6状态下基体微观组织发生显著变化,逐渐由GP区+θ″/θ′相向T1+θ″/θ′相转变,并伴随θ″/θ′相数量的减少,而T8状态下基体微观组织由T1+θ″/θ′相转变为以T1相为主导的微观组织。3%的预拉伸增加了基体中的位错密度,可作为T1相优先形核位置,导致相同时效温度下,T8态合金的屈服强度明显高于T6态合金,但对抗拉强度的影响不明显,这是沉淀强化效果优于加工硬化效果导致的。T6状态下(165℃,24 h)时效处理获得最佳的强塑性(抗拉强度584 MPa,屈服强度526 MPa,断后伸长率11.5%),而T8状态下3%预拉伸+(155℃,24 h)时效获得最佳的强塑性匹配(抗拉强度622 MPa,屈服强度600 MPa,断后伸长率11.8%)。In this paper,TEM,SEM,EBSD and room temperature tensile tests were used to study the effects of aging temperature and pre-stretching process on the microstructure and properties of spray-formed 2195 Al-Li alloy extruded rods.The results show that,when the aging temperature is lower than 145℃,the GP region+θ″/θ′phase is mainly formed in the matrix microstructure of the 2195 Al-Li alloy in the T6 state,while T1+θ″/θ′phase is mainly formed in the matrix microstructure in the T8 state,and the grain boundary precipitation-free band width of the alloy in the T8 state is significantly lower than that in the T6 state.When the aging temperature increases to 155℃,the T6 state organization changes significantly,and gradually transforms from the GP region+θ″/θ′phase to the T1+θ″/θ′phase,accompanied by an increase in the number ofθ″/θ′phases,and the microstructure in the T8 state is transformed from the T1+θ″/θ′phase to the T1 phase-dominated microstructure.The dislocations and entanglements generate during the pre-stretching process contribute to the fine and uniform precipitation of the T1 phase,making the yield strength of the T8 state significantly higher than that of the T6 state at the same aging temperature.Due to the precipitate T1 phase in the process of aging,precipitation strengthening effect is better than work hardening effect.The best strong plasticity(tensile strength 584 MPa,yield strength 526 MPa,elongation after fracture 11.5%)is obtained by(165℃,24 h)aging in T6 state,while 3%pre-stretching+(155℃,24 h)aging in T8 state is the best strong-plastic matching(tensile strength 622 MPa,yield strength 600 MPa,elongation after fracture 11.8%).

关 键 词：喷射成形 铝锂合金 时效温度 时效析出相 力学性能 

分 类 号：TG379[金属学及工艺—金属压力加工]