摘要
通过微观组织观察、慢应变速率拉伸试验对某动车电气屏柜用7003-T5铝合金型材在不同温度3.5%中性NaCl溶液中的应力腐蚀行为进行研究。结果表明:铝合金型材横截面呈现大小不均匀的完全再结晶等轴晶组织,晶粒内以及晶界处分布较多点状的η相(MgZn2),且在晶界处呈连续分布。在25℃的3.5%的中性NaCl溶液中,应力腐蚀敏感性指数高达8.75%;随着温度升高至50℃,应力腐蚀敏感指数增加至11.77%,表现为较高的应力腐蚀敏感性;断口表面裂纹形貌呈现沿晶开裂,且在金属刻面处可见清晰的"冰糖"状花样,为典型的应力腐蚀开裂,表明合金具有较高的应力腐蚀敏感性,腐蚀介质以及拉应力的存在是导致应力腐蚀开裂发生的直接因素。
The stress corrosion cracking behavior of 7003-T5 aluminum alloy were investigated in 3.5%NaCl solution at different temperature by means of microstructure characterization and slow strain rate tensile tests.The results indicate that varisized equiaxed grains are observed in the cross section,which suggests completed recrystallization occurred.The majority of precipitation:fine and punctateη(MgZn2)presents in the grain,but also aggregates at the grain boundary.The stress corrosion cracking sensitivity index is as high as 8.75%in the neutral 3.5%NaCl solution at room temperature.It increases to 11.74%as the temperature increases to 50℃,which means that 7003-T5 aluminum alloy is highly sensitivity to stress corrosion cracking.Fracture morphologies show that crack propagation is typified by an intergranular cracking,meanwhile,the ice sugar pattern is apparent on the facet.These features manifest the stress corrosion cracking.It’s worth noting that stress corrosion sensitivity of Al alloy,corrosive medium and tensile stress are the direct factors resulting in stress corrosion cracking.
作者
剡苏荣
丁浩
刘雄
王向东
YAN Su-rong;DING Hao;LIU Xiong;WANG Xiang-dong(Zhuzhou CRRC Times Electric Co.,Ltd,Zhuzhou 412001,China)
出处
《内燃机与配件》
2020年第19期118-122,共5页
Internal Combustion Engine & Parts
