一种新型超高强铝锂合金薄板的时效行为与微观组织  

Aging Behavior and Microstructure of a New Super-High Strength Al-Li Alloy Sheet

作　　者：李劲风[1] 陈永来[2] 张绪虎[2] 张健[1] 郑子樵[1] LI Jinfeng CHEN Yonglai ZHANG Xuhu ZHANG Jian ZHENG Ziqiao(School of Materials Science and Engineering, Central South University, Changsha 410083 Aerospace Research Institute of Materials ＆ Processing Technology, Beijing 100076)

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

出　　处：《宇航材料工艺》2016年第5期62-67,共6页Aerospace Materials & Technology

基　　金：863项目(No.2013AA032401);中南大学教师基金(No.2013JSJJ 001)

摘　　要：为优化一种新型超高强Al-Cu-Li-X合金2 mm厚度薄板的热处理工艺,本文研究了其不同时效条件下的力学性能和微观组织。结果表明：预变形为6%时,T8态长时间（20~120 h）时效时可保持600MPa以上的抗拉强度。T8态时效时合金强化相为大量T1相（Al2Cu Li）和部分θ＇相（Al2Cu）,T6态时效时还可析出极少量S＇相（Al2CuMg）。预变形可促进T1相细小弥散析出,但抑制θ＇相及S＇相的析出。6%以下预变形可有效提高合金T8态时效的强度。6%以上预变形量的T8态时效合金中T1相密度明显增加,尺寸显著降低,θ＇相减少,但相应合金抗拉强度的增量很小,而延伸率急剧下降;过大预变形（15%）则导致θ＇相消失。To optimize the heat treatment processing of a new super-high strength Al-Cu-Li-X alloy sheet with 2 mm thickness,the mechanical properties and microstructures of the alloy with different aging treatment were investigated. Its tensile strength kept higher than 600 MPa after a long time（ 20 - 120 h） of T8 aging with 6% pre-deformation. The strengthening phases in T8 temper were a large number of T1（ Al2CuLi） precipitates and some（ Al2Cu） precipitates. A very small amount of S＇（ Al2CuMg） precipitates also formed in T6 aging. Pre-deformation accelerated dispersive and fine precipitation of T1 phases,but inhibited the precipitation of θ＇ and S＇ phases. At pre-deformation lower than 6%,the tensile strength of the T8-aged alloy was effectively increased with pre-deformation. At pre-deformation higher than 6%,with pre-deformation increasing,T1 number density was obviously increased and its size decreased,θ＇ fraction reduced,and the strength enhancement caused by pre-deformation was decreased and elongation was much lowered. Excessively high pre-deformation（ 15%） made θ＇ precipitates disappear.

关 键 词：超高强铝锂合金 时效行为 微观组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]