应变速率条件下第二相对7A52铝合金搅拌摩擦焊焊缝应力腐蚀性能的影响  

Effects of secondary phases on stress corrosion property of friction stir welded seam of 7A52 aluminum alloy under different strain rates

作　　者：赵军军[1] 李奇[2] 蔡志海[1] 张平[1] 

机构地区：[1]装甲兵工程学院装备再制造工程系,北京100072 [2]装甲兵工程学院机械工程系,北京100072

出　　处：《焊接学报》2013年第8期63-66,75,共5页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(50801066)

摘　　要：采用慢应变速率拉伸试验,结合扫描电镜、能谱分析仪研究了第二相对7A52铝合金搅拌摩擦焊(FSW)焊缝应力腐蚀性能的影响.结果表明,FSW焊缝在3.5%NaCl溶液中,应力腐蚀开裂(SCC)均发生在后退侧的热影响区,断裂位置与显微硬度曲线中硬度最低区域相对应.焊缝的SCC敏感性在1×10-6s-1条件下最高,在1×10-5s-1条件下最低,不同第二相对FSW焊缝应力腐蚀裂纹形核和扩展的影响是不同的:Al9Fe0.84Mn2.16Si容易引发裂纹的萌生和扩展,Mg2Si被腐蚀留下的点蚀坑引发的裂纹相对较小.The effects of secondary phases on stress corrosion property of friction stir welded(FSW) seam of 7A52 aluminum alloy were investigated with SEM-EDS during low stress rate test(SSRT).The experimental results indicate that the stress corrosion cracking(SCC) occurred on the retreating side of HAZ in FSW seam in 3.5%NaCl solution.The fracture position was corresponding to the position of minimum microhardness value in FSW seam.The SCC susceptibility of FSW seam was highest at strain rate of 1×10-6 s-1 and lowest at 1×10-5s-1.Different secondary phases had different effects on the initiation and growth of stress corrosion cracks.Al9Fe0.84Mn2.16Si easily induced the initiation and growth of cracks,however,the pitting resulted from the dissolved Mg2Si could only initiate small cracks.

关 键 词：7A52铝合金 搅拌摩擦焊焊缝 应力腐蚀开裂 第二相 

分 类 号：TG453[金属学及工艺—焊接]