Abstract The corrosion properties of selective laser melted (SLM) and of additionally heat-treated (T6) Al-3.5Cu-1.5 Mg–1Si samples were assessed in 0.001 M and 0.1 M NaCl solutions (pH 7) by means of electrochemical polarization measurements and SEM surface analysis. In both solutions these new alloy types exhibited improved corrosion behavior compared to wrought and heat-treated AA 2024 reference states. This is attributable to more refined microstructural states and to the formation of particular phases. The SLM samples comprise finely dispersed Q-phase particles which act cathodic and thus, trigger adjacent matrix phase dissolution. Additional T6 heat treatment was efficient for attaining the lowest corrosion current density of ~0.04 μA/cm2 and a widening of the anodic passive range to ~400 mV in 0.1 M NaCl. Only this alloy state shows a repassivation ability upon reverse scanning. T6 treatment yields mainly the Mg2Si phase acting as local anode and a widely passive Al-based matrix phase. Altogether, SLM processing with final heat treatment of the Al-3.5Cu-1.5 Mg–1Si alloy is suitable for achieving not only superior mechanical performance but also improved corrosion stability.

中文翻译：

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激光选区熔化热处理制备的Al-3.5Cu-1.5 Mg-1Si合金的腐蚀

摘要 通过电化学极化测量，在 0.001 M 和 0.1 M NaCl 溶液 (pH 7) 中评估了选择性激光熔化 (SLM) 和额外热处理 (T6) Al-3.5Cu-1.5 Mg-1Si 样品的腐蚀性能和 SEM 表面分析。在这两种解决方案中，与锻造和热处理的 AA 2024 参考状态相比，这些新合金类型表现出更好的腐蚀行为。这归因于更精细的微观结构状态和特定相的形成。SLM 样品包含精细分散的 Q 相颗粒，这些颗粒起到阴极作用，从而引发相邻的基质相溶解。额外的 T6 热处理可有效实现 ~0.04 μA/cm2 的最低腐蚀电流密度，并将阳极钝化范围扩大至 0.1 M NaCl 中的 ~400 mV。只有这种合金状态在反向扫描时显示出再钝化能力。T6 处理主要产生充当局部阳极的 Mg2Si 相和广泛钝化的铝基基体相。总之，对 Al-3.5Cu-1.5 Mg-1Si 合金进行最终热处理的 SLM 加工不仅适用于实现优异的机械性能，而且还适用于提高腐蚀稳定性。