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通过常规拉伸、慢应变速率拉伸和晶间腐蚀实验研究了T6及双级时效处理对6156铝合金力学性能与腐蚀性能的影响,并采用透射电镜(TEM)观察了析出相特征。结果表明:6156合金在T6欠时效状态下晶内析出相主要为GP区,晶界无明显析出相;T6峰时效晶内析出相主要为β″相,出现少量的Q′相,晶界析出物呈连续分布,合金虽然具有最高强度,但晶间腐蚀严重,应力腐蚀敏感性最大;随时效时间延长,Q′相增多并逐渐粗化,晶界析出物粗大非连续分布;T78时效态晶内析出大量的Q′相,晶界析出相球化且析出相之间的间距增大,呈断续分布,无沉淀析出带(PFZ)变宽,因此相比T6态而言T78状态合金强度损失不大而耐蚀性得到明显提高。
The effects of T6 and two-stage aging treatments on the mechanical properties and corrosion resistance of 6156 aluminum alloy were studied by conventional tensile tests, slow strain rate tensile tests and intergranular corrosion tests. The characteristics of precipitated phases were observed by transmission electron microscopy (TEM). The results show that the precipitated phase of 6156 alloy is mainly GP zone and the grain boundary has no obvious precipitates under T6 under-aging condition. The precipitated phase of T6 peak is mainly β "phase with a small amount of Q ’phase precipitated Although the alloy has the highest strength, the intergranular corrosion is serious and the stress corrosion sensitivity is the most. With the aging time prolongs, the Q ’phase increases and coarsens gradually, and the grain boundary precipitates are coarse and non-continuous; A large number of Q ’phases are precipitated in the grain boundaries, and grain boundaries are precipitated in the grain boundaries and the spacing between the precipitated phases increases and is intermittent. No precipitation zone (PFZ) is broadened. Therefore, the T78 state alloy strength Loss is not large and corrosion resistance has been significantly improved.