Al-3.7Cu-0.8Mg-0.7Mn合金应力腐蚀性能研究

Stress Corrosion Behavior of Al-3.7Cu-0.8Mg-0.7Mn Alloy

通过慢应变速率拉伸测试法(SSRT),研究了Al-3.7Cu-0.8Mg-0.7Mn合金在不同温度、不同腐蚀介质中的应力腐蚀开裂(SCC)行为,利用金相显微镜观察断口侧面的腐蚀形貌,借助SEM分析断口形貌。结果表明,在3.5%的NaCl溶液中,合金的应力腐蚀敏感性随着温度升高而增大,断口形貌呈现典型的沿晶断裂;25℃下,合金分别在3.5%的NaCl,3.5%的NaCl+0.5%的H_2O_2,3.5%的NaCl+1.0%的H_2O_2腐蚀介质中的应力腐蚀指数(ISSRT值)分别为3.17%、8.83%、14.4%,表现出很强的应力腐蚀敏感性,容易发生断裂。

The stress corrosion cracking（SCC）behaviors of Al-3.7 Cu-0.8 Mg-0.7 Mn alloy at various temperatures and corrosive media were investigated by slow strain rate test（SSRT）.The fracture surface was observed by metallographic microscope and the fracture morphology was analyzed by SEM.The results show that the alloy exhibits the strong stress corrosion susceptibility in 3.5% NaCl solution at 25℃,40 ℃and 50℃,and it is increased with increasing in temperature.The fracture surfaces exhibit typical intergranular fracture.At 25 ℃,the values of the intergranular corrosion（ISSRT）reach 3.17%,8.83%and 14.4%corresponded to 3.5% NaCl,3.5% NaCl＋0.5% H2O2,3.5% NaCl＋1.0% H2O2 conditions,respectively.The alloy presents the strong stress corrosion susceptibility with the changes of corrosion conditions,so fracture is easily formed.