第二相对7A52铝合金应力腐蚀性能的影响研究  

Effects of Secondary Phases on Stress Corrosion Property of 7A52 Aluminum Alloy

作　　者：蔡志海[1] 李奇[1] 王宪成[1] 底月兰[1] 

机构地区：[1]装甲兵工程学院机械产品再制造国家工程研究中心,北京100072

出　　处：《稀有金属材料与工程》2013年第S2期541-544,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50901089);装甲兵工程学院创新基金资助(2012CJ070)

摘　　要：通过慢应变速率拉伸试验,结合扫描电镜和能谱分析,对7A52铝合金在空气中和3.5%NaCl溶液中的应力腐蚀开裂(SCC)进行了研究,用面积收缩率损失系数表征了合金的SCC敏感性。结果表明:合金的SCC敏感性在应变速率为1×10-6 s-1时最高,在1×10-5 s-1时最低。不同第二相对合金应力腐蚀裂纹形核和扩展的影响是不同的:AlMn0.75Fe2.25造成了应力集中,其被折断或与界面脱离形成最初开裂的微孔,微孔逐渐长大、聚合,在拉应力作用下沿垂直拉应力方向扩张,形成细微裂纹;而Mg2Si被腐蚀留下的点蚀坑只会引发细微裂纹。可见,合金的第二相在应力腐蚀过程中起重要作用。The stress corrosion cracking(SCC) behaviour of 7A52 aluminum alloy in air and in 3.5% NaCl solution was researched by slow strain rate tests and SEM-EDS.The SCC susceptibility was estimated with the loss of the reduction in area.The results indicate that the SCC susceptibility of 7A52 aluminium alloy in 3.5% NaCl solution is the highest at strain rate of 1×10-6 s-1.The lowest one is under the condition of 1×10-5 s-1.Different secondary phases have different effects on the initiation and growth of stress corrosion cracks.AlMn0.75Fe2.25 were broke off or fell off from the matrix because of stress concentration on them.Both factors initiated micropores which resulted in microcracks.The existence of AlMn0.75Fe2.25 in the microstructure may play an important role in understanding the SCC mechanisms of 7A52 aluminium alloy.Dissolved Mg2Si leave pittings which could only initiate small cracks.Secondary phases play an important role in stress corrosion of 7A52 aluminum alloy.

关 键 词：7A52铝合金 应力腐蚀 应力腐蚀开裂敏感性 第二相 

分 类 号：TG146.21[一般工业技术—材料科学与工程]