In our previous work, die cast LA42 (Mg–4La–2.5Al–0.3Mn, wt.%) alloy with an excellent combination of thermal-conducting performance and mechanical properties was developed. This study, taking commercial die cast AZ91 (Mg-9Al-1 Zn, wt.%) alloy as a comparison, investigates the microstructure and corrosion behavior of the LA42 alloy in chloride-containing environment. The findings revealed that the microstructure of die cast LA42 alloy displays an Al-depleted α-Mg dendrite and a network shape eutectic phase comprising of eutectic α-Mg and lamellar Al₁₁La₃. The LA42 alloy exhibited slightly inferior corrosion resistance and deeper corrosion pits than the AZ91 alloy, which were related to the interphase attack and the presence of a layer of corrosion products containing more magnesium hydroxide of the LA42 alloy. The corrosion behavior of the LA42 alloy was characterized by an interphase attack on the periphery of Al-depleted α-Mg dendrite adjacent to Al₁₁La₃, which primarily ascribed to the relatively lower potential of the Al-depleted α-Mg phase and the interfacial reactivity between it and the adjacent Al₁₁La₃, whereas the AZ91 alloy showed a trait of preferential corrosion of the interior of α-Mg dendrite for its lowest potential among different phases. This comprehensive research can provide a guidance for future alloy design of Mg-Al-La alloys and their industrial applications.

在我们之前的工作中，开发了具有良好导热性能和机械性能的压铸 LA42（Mg-4La-2.5Al-0.3Mn，wt.%）合金。本研究以商用压铸 AZ91 (Mg-9Al-1 Zn, wt.%) 合金为对比，研究了 LA42 合金在含氯化物环境中的显微组织和腐蚀行为。研究结果表明，压铸 LA42 合金的微观结构显示出贫铝的 α-Mg 枝晶和由共晶 α-Mg 和层状 Al ₁₁ La _{3组成的网络状共晶相}. 与AZ91合金相比，LA42合金的耐蚀性略差，腐蚀坑更深，这与LA42合金的相间侵蚀和一层含有较多氢氧化镁的腐蚀产物有关。_{LA42 合金的腐蚀行为表现为对与 Al 11} La ₃相邻的贫铝 α-Mg 枝晶外围的相间侵蚀，这主要归因于贫铝 α-Mg 相的相对较低的电位和它与相邻的Al ₁₁ La _{3之间的界面反应}，而 AZ91 合金显示出优先腐蚀 α-Mg 枝晶内部的特征，因为它在不同相中具有最低的电位。该综合研究可为未来Mg-Al-La合金的合金设计及其工业应用提供指导。