时效制度对喷射成形7055铝合金抗应力腐蚀性能的影响  

Effect of aging process on stress corrosion resistance of spray forming 7055 aluminum alloy

作　　者：许俊华[1] 王贵会[1] 喻利花[1] 李浩[1] 张豪[2,3] 范曦 

机构地区：[1]江苏科技大学先进焊接技术江苏省重点实验室,镇江212003 [2]上海交通大学金属基复合材料国家重点实验室,上海200030 [3]江苏豪然喷射成形合金有限公司,镇江212009

出　　处：《粉末冶金材料科学与工程》2012年第5期592-598,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：江苏省科技支撑计划资助项目(BE2009126;BE2009185);江苏高校优势学科建设工程资助项目

摘　　要：对喷射成形7055铝合金分别进行T6时效和双级时效处理,然后在空气和3.5%NaCl溶液中进行慢应变速率拉伸实验,测定时效处理后合金的电导率,用扫描电镜观察合金的断口形貌。研究7055铝合金在T6及3种不同双级时效态下在空气和3.5%NaCl溶液中的应力腐蚀开裂行为。结果表明:7055铝合金只在一定的应变速率下应力腐蚀敏感性明显;相同时效制度下,4种应变速率(1.3×10 6,0.8×10 6,0.5×10 6和0.2×10 6s 1)中,应变速率为0.5×10 6s 1时应力腐蚀敏感性大;T6态合金的抗应力腐蚀性能最差,二级时效时间达到15 h后合金对应力腐蚀不敏感;应变速率为0.5×10 6s 1时,喷射成形7055铝合金的应力腐蚀断口的断裂方式为准解理断裂,在惰性介质中慢应变速率拉伸断口断裂方式为韧窝断口。Slow strain rate tensile tests of the spray forming 7055 aluminum alloy with aging systems of T6 and three different duplex aging systems were done in the air and 3.5%（mass fraction） NaCl solution.The conductivities were tested and fracture morphologies of aged 7055 aluminum alloy were determined and observed by SEM.The stress corrosion cracking behavior of 7055 aluminum alloy with T6 and three duplex aging systems in the air and 3.5%（mass fraction） NaCl solution were studied.The results show that,stress corrosion cracking susceptibility of spray forming 7055 aluminum alloy is obvious only at some strain rate;Under the same aging system,stress corrosion cracking sensitivity of spray forming 7055 aluminum alloy is the biggest at the strain rate of 0.5×10 6s 1 among four strain rates of 1.3×10 6,0.8×10 6,0.5×10 6and 0.2×10 6s 1.The stress corrosion cracking resistance of 7055-T6 aluminum alloy is worst than others.After the time of secondary ageing reaches 15 h,7055 aluminum alloy is not sensitive to stress corrosion cracking;At the strain rate of 0.5×10 6s 1in the 3.5%（mass fraction） NaCl solution,the fracture way of spray forming 7055 alloy is sub-cleavage fracture,while in the air,the fracture way of sample is dimple fracture.

关 键 词：喷射成形7055铝合金 单级时效 双级时效 慢应变速率拉伸 准解理断裂 应力腐蚀敏感性 

分 类 号：TG172.9[金属学及工艺—金属表面处理]