摘要
用慢应变速率拉伸测试、金相(OM)、扫描电镜(SEM)及透射电镜(TEM)分析等方法研究了Al-3.88Cu-1.18Mg-0.31Mn铝合金在T6时效状态下的应力腐蚀开裂(SCC)行为。结果表明:随着时效时间的延长,合金的应力腐蚀开裂敏感性逐渐降低。合金应力腐蚀与晶间腐蚀具有正相关性,其本质是晶界与晶内存在电位差,形成电偶腐蚀,在应力作用下,导致晶界连续腐蚀。在时效过程中,晶界S'(S)相由连续分布逐渐转变为断续分布,晶内析出相由GPB区逐渐转变为S'(S)相,并形成PFZ。这样的微观组织转变使合金应力腐蚀开裂敏感性随着时效的进行逐渐降低。
The stress corrosion cracking（ SCC） performance of aluminum alloy Al-3. 88Cu-1. 18Mg-0. 31 Mn in T6 temper was investigated by using slow strain rate tension,optical microscope,scanning electron microscope and transmission electron microscope. The results show that the stress corrosion cracking susceptibility of the alloy reduces gradually with the increase of aging time. Stress corrosion cracking has positive correlation with intergranular corrosion,whose essence is that the potential difference between grain and grain boundaries produces galvanic corrosion and results in continuous grain boundary corrosion under stress.During aging,the S＇（ S） precipitates of grain boundary changed from continuous distribution gradually to discontinuous distribution,the precipitates of grain changed from GPB zone gradually to S＇（ S） phase and PFZ produced. These microstructural transformation make the stress corrosion cracking sensitivity of the alloy decreased with aging proceed.
出处
《材料开发与应用》
CAS
2015年第3期31-36,共6页
Development and Application of Materials
