摘要
Microstructural characterization,mass loss tests,hydrogen evolution tests,electrochemical measurements,and corrosion morphology observations were conducted to investigate the effect of the secondary phases on the corrosion behavior of the as-cast Mg−7Sn−1Zn−1Y(TZW711)alloy after solution treatment(T4)and aging treatment(T6).The results show that the T4-TZW711 alloy possesses the highest corrosion resistance in the early corrosion stage.This is because the dissolution of Mg2Sn reduces the cathodic current density and increases the charge transfer resistance(Rct).When the corrosion time is prolonged,the undissolved and clustered MgSnY phase will peel off from the T4-TZW711 alloy surface,thereby increasing the corrosion rate of the alloy.After aging treatment,the undissolved MgSnY phase is dispersed,which results in a lower localized corrosion sensitivity of T6-TZW711 alloy than that of the T4-TZW711 alloy,suggesting that the T6 treatment can enhance the corrosion resistance of Mg−7Sn−1Zn−1Y alloys.
通过显微组织表征、质量损失实验、析氢实验、电化学测试和腐蚀形貌观察等手段研究了第二相对经固溶(T4)和时效(T6)热处理后铸态Mg-7Sn-1Zn-1Y(TZW711)合金腐蚀行为的影响。结果表明:T4-TZW711合金在早期腐蚀阶段具有最高的耐蚀性,这是因为Mg_2Sn的固溶降低了合金的阴极电流密度,并增加了合金的电荷转移电阻(R_(ct))。但当腐蚀时间延长时,未固溶且聚集的MgSnY相从T4-TZW711合金表面剥落,从而提高其腐蚀速率。经时效热处理后,未固溶的MgSnY相分布变得离散,使T6-TZW711合金的局部腐蚀敏感性低于T4-TZW711合金。此结果表明,T6处理能提高Mg-7Sn-1Zn-1Y合金的耐蚀性。
基金
National Natural Science Foundation of China(Nos.52301041,52022017,52065009,52371005)
Special Fund for Special Posts of Guizhou University,China(No.[2023]26)
Science and Technology Planning Project of Guizhou Province,China(No.ZK2021269)
Fundamental Research Funds for the Central Universities,China(No.DUT23YG104)。
