腐蚀环境下2E12航空铝合金疲劳裂纹扩展行为研究  

Effect of Corrosive Environment on Fatigue Crack Propagation of 2E12 Aerospace Aluminum Alloy

作　　者：杨胜[1] 易丹青[1] 杨守杰[2] 钟利[3] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]北京航空材料研究院,北京100095 [3]东北轻合金有限公司,哈尔滨115001

出　　处：《材料工程》2007年第12期26-29,34,共5页Journal of Materials Engineering

基　　金：国家"973"重点基础研究发展规划项目(2005CB623705)

摘　　要：采用SEM,TEM及疲劳性能测试等分析测试手段,系统地研究了2E12铝合金在室温空气、潮湿气体及盐雾环境下的疲劳裂纹扩展速率。结果发现2E12合金具有良好的疲劳性能,疲劳裂纹扩展速率优于国外的2524铝合金。利用修正的Paris公式分析腐蚀介质对合金的疲劳裂纹扩展性能影响轻重程度依次为:室温空气<潮湿气体<盐雾环境。不同环境条件下合金的疲劳裂纹形貌均表现微观裂纹扩展的晶界小平面、宏观裂纹扩展的疲劳条纹以及剪切撕裂的微观结构。在腐蚀环境下,宏观裂纹扩展表现出更多的脆性裂纹扩展特征,氢脆导致塑性区脆化及腐蚀诱导的阳极溶解是导致裂纹扩展性能降低的原因。The fatigue crack growth behavior of 2E12 aluminum alloy was studied in air, humidity air and 3.5% （mass fraction）NaCl salt fog by SEM, TEM and fatigue property testing. The results showed that the fatigue crack growth of 2E12 was better than that of 2524 aluminum alloy. The growth rates of fatigue crack in different environments, were analyzed and compared by Paris equa- tion. Fatigue crack growth rates in salt fog was highest, somewhat less in humidity air and lowest in air. Furthermore, the fractographic features such as small crystallographic face of micro-crack growth, fatigue striation of macro-crack growth and microstructure of shear zone reflected the fatigue crack growth behavior of alloy in a given environment, more brittle striations were observed in humidity air and salt fog. The increased crack growth rates was due to a combination of hydrogen embrittlement and anodic dissolution at the crack tip.

关 键 词：2E12铝合金 腐蚀 疲劳裂纹扩展 氢脆 

分 类 号：TG111.8[金属学及工艺—物理冶金]