Cu含量对T6及T8态时效超高强铝锂合金时效析出相和强度的不同影响  

Different Effects of Cu Content on Aging Precipitation and Strength of T6-Aged and T8-Aged Ultra-High Strength Al-Li Alloys

作　　者：曾广俊 李昊然 李玉琢 李劲风[1] 马鹏程 陈永来[2] 张绪虎[2] ZENG Guangjun;LI Haoran;LI Yuzhuo;LI Jinfeng;MA Pengcheng;CHEN Yonglai;ZHANG Xuhu(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Aerospace Research Institute of Materials&Processing Technology,Beijing 100076,China)

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]航天材料及工艺研究所,北京100076

出　　处：《材料研究与应用》2023年第2期277-285,共9页Materials Research and Application

基　　金：863项目(2013AA032401)。

摘　　要：采用透射电子显微镜和室温拉伸性能测试,研究了Cu含量对Mg、Ag、Zn复合微合金化的新型超高强铝锂合金Al-x Cu-1.2Li-X(x=4.2、4.5)冷轧薄板的时效析出相和强度的影响。结果表明:T6(165℃/24 h)及T8态时效时,不同Cu含量的超高强铝锂合金的析出相包括大量的T_(1)相、较多的θ’相、部分GP区和δ’/GP/δ’复合相以及少量的S’相;T6态时效时,高Cu含量更有利于合金中GP区及θ’相的析出而导致T_(1)相的数密度减少,因而强度较低、伸长率相对较高;T8时效时,高Cu含量则有利于T_(1)相和θ’相的同时析出,导致其数密度大幅度增加,同时S’相和GP区的析出受到抑制,因此随着Cu含量增加,合金强度增加、伸长率小幅度下降;T8态时效后,高Cu含量新型超高强铝锂合金的抗拉强度达661.7 MPa、伸长率约为6%。Using transmission electron microscopy and tensile property tests,the effects of Cu content on the aging precipitates and strength of the ultra-high strength alloy Al-xCu-1.2Li-X(x=4.2,4.5)cold-rolled sheets microalloyed with Mg,Ag,and Zn were studied.The results show that the strengthening precipitates of the T6-aged and T8-aged alloys include a large amount of T_(1)(Al_(2)CuLi)precipitates,a considerable amount ofθ′(Al2Cu)precipitates,part of GP zones andδ′/GP/δ′composite phases,as well as a small amount of S′precipitates.The higher Cu content in the T6-aged alloy facilitates the precipitation of GP zones andθ′precipitates,whereas the number density of T_(1) precipitates decreases,which results in the reduction of strength and slight increase of elongation.With the increase of Cu content in T8-aged alloy,the number density of T_(1) andθ′precipitates significantly increases,simultaneously inhibiting the nucleation of GP zones and S′precipitates,contributing to an increase in the strength of T8-aged alloy with a slight decrease of elongation.The tensile strength of the T8-aged ultra-high strength Al-Li alloy with higher Cu content approaches to 661.7 MPa with the elongation of around 6%.

关 键 词：超高强铝锂合金 CU含量 时效制度 微观组织 强度 

分 类 号：TG164.2[金属学及工艺—热处理]