等径角挤压制备的超细晶Al-5%Cu合金块材的腐蚀行为

Corrosion behavior of ultra-fine grain bulk Al-5%Cu alloy fabricated by equal-channel angular pressing

采用全浸泡腐蚀和电化学腐蚀研究等径角挤压制备的超细晶铝铜合金块材在氯化钠溶液中的腐蚀行为。结果表明:超细晶铝铜合金中基体相α(Al)晶粒细小(为200～300nm);铸态组织中网状θ相(Al2Cu)破碎、细化成10μm左右的颗粒并均匀分布于形变α(Al)基体上;形变细化提高铝铜合金在氯化钠介质中的耐蚀性能,表现出全浸泡腐蚀中更轻的腐蚀程度、电化学测试中更大的极化电阻、更正的自腐蚀电位和点蚀电位、更小的腐蚀电流密度。

The effect of strain-induced grain refinement on the corrosion behavior of ultra-fine grain bulk Al-5%Cu alloy fabricated by equal-channel angular pressing（ECAP） was investigated by constant immersion tests and electrochemical corrosion in NaCl solution.The results show that the ECAP Al-Cu alloy obtains a finer grain size（200-300 nm） of α（Al） matrix,and the original net-like coarse θ phase is also broken into uniformly distributed fine particles with grain size of about 10 μm.The corrosion resistance of ultra-fine grain（UFG） Al-Cu alloy is obviously improved with alleviated corrosion damaged morphologies in constant immersion test,and the alloy has more positive open circuit potential（φ0）,higher fitted Rt values,more positive self corrosion potential（φp） and lower corrosion current（Jc） values in electrochemical measurements.