自然时效对Al-6.5Zn-2.3Mg-2.2Cu合金厚板组织性能的影响  

Effect of natural aging on microstructure and properties of Al-6.5Zn-2.3Mg-2.2Cu aluminum alloy thick plate

作　　者：左德运[1] 温凯 任伟才[1] 李锡武 李志辉 谭艺哲 ZUO Deyun;WEN Kai;REN Weicai;LI Xiwu;LI Zhihui;TAN Yizhe(Northeast Light Alloy Co.,Ltd.,Harbin 150060,China;State Key Laboratory of Nonferrous Metals and Processes,China GRINM Group Co.,Ltd.,Beijing 100088,China;GRIMAT Engineering Institute Co.,Ltd.,Beijing 101407,China)

机构地区：[1]东北轻合金有限责任公司,黑龙江哈尔滨150060 [2]中国有研科技集团有限公司有色金属材料制备加工国家重点实验室,北京100088 [3]有研工程技术研究院有限公司,北京101407

出　　处：《轻合金加工技术》2024年第6期33-40,共8页Light Alloy Fabrication Technology

基　　金：国家重点研发计划项目课题(2023YFB3710502)。

摘　　要：商用7×××系铝合金产品人工时效前一般会经历自然时效,自然时效时间的长短直接决定产品的生产制备流程。本试验研究了工业化制备的Al-6.5Zn-2.3Mg-2.2Cu合金厚板在不同的自然时效阶段经人工时效处理后的组织及性能,并重点分析了短时自然时效(0.125~21 d)及长时自然时效(30~360 d)对合金不同时效状态的影响。研究结果表明:自然时效0.125~21 d,T6态合金的强度持续降低,抗拉和屈服强度的降幅分别为14 MPa和17 MPa,伸长率在13.6%~15.6%的范围内波动;基体析出相主要为GPII区和η′相,晶界析出相呈断续分布。自然时效3~360 d时,T6态合金的强度、伸长率和断裂韧性均在一定范围内波动,无明显的变化规律,基体析出相主要为η′相且分布密集,晶界析出相呈断续分布。自然时效3~105 d时,T76态合金的拉伸性能和断裂韧性同样在一定范围内波动,无明显的变化规律,基体析出相尺寸粗大、分布分散,主要为η′相和η相,晶界析出相同样呈断续分布。The production processes of commercial 7×××series aluminum alloy products typically include a period of natural aging before artificial aging.The duration of natural aging directly affects the production process of the product.This study investigated the microstructure and properties of industrially-fabricated Al-6.5Zn-2.3Mg-2.2Cu alloy thick plates after artificial aging at different stages of natural aging,focusing on the effects of shortterm natural aging(0.125 to 21 days)and long-term natural aging(30 to 360 days)on the alloy in different aging states.The results indicate that during natural aging from 0.125 to 21 days,the strength of the T6-tempered alloy consistently decreases,with reductions in tensile strength and yield strength of 14 MPa and 17 MPa,respectively,while the elongation fluctuates within the range of 13.6%to 15.6%.The primary precipitates in the matrix are GPII zones andη′phases,and the grain boundary precipitates are discontinuously distributed.During natural aging from 3 days to 360 days,the strength,elongation,and fracture toughness of the T6-tempered alloy fluctuate within a certain range without a clear pattern,with the primary precipitates in the matrix being densely-distributedη′phases and the grain boundary precipitates being discontinuously distributed.During natural aging from 3 days to 105 days,the tensile properties and fracture toughness of the T76-tempered alloy also fluctuated within a certain range without a clear pattern,with the primary precipitates in the matrix being coarse and sparsely distributedη′andηphases,and the grain boundary precipitates being discontinuously distributed.

关 键 词：Al-6.5Zn-2.3Mg-2.2Cu合金 自然时效 析出特征 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG156.92[金属学及工艺—金属材料]