In this paper, the precipitates of the Mg‒3 wt%Nd alloy in the as-cast state and after heat treatment at 540 ℃ for 12 h were investigated and related to the corrosion behavior in saline solution. For the as-cast specimen, the network and spherical β-phases (Mg₁₂Nd) act as the anodes relative to Mg matrix at the initial stage of immersion in saline solution. With increasing the immersion time, the intergranular corrosion caused by the preferential dissolution of the reticular β-phase leads to the detachment of Mg fragments. For the heat-treated specimen, the plate-shaped β₁-phases (Mg₃Nd) distributed evenly in the grain interior act as the micro-cathodes. The corrosion pits are prone to extend horizontally and connected each other, resulting in an uniform corrosion status and a relatively lower corrosion rate. This result is helpful for developing the biomedical Mg‒Nd base alloys with a good degradation property by adjusting the precipitation of intermetallics.

Graphical Abstract

中文翻译：

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Mg12Nd和Mg3Nd对Mg-3 wt%Nd合金在盐溶液中腐蚀行为的影响

本文研究了铸态 Mg-3 wt%Nd 合金在 540 ℃ 热处理 12 h 后的析出物及其在盐溶液中的腐蚀行为。对于铸态试样，在浸入盐溶液的初始阶段，网络和球形β相（Mg ₁₂ Nd）相对于Mg基体充当阳极。随着浸泡时间的增加，网状β相优先溶解引起的晶间腐蚀导致Mg碎片脱离。对于热处理试样，板状β ₁相（Mg ₃Nd) 均匀分布在晶粒内部充当微阴极。腐蚀坑易水平延伸并相互连接，腐蚀状态均匀，腐蚀速率相对较低。该结果有助于通过调节金属间化合物的析出来开发具有良好降解性能的生物医用Mg-Nd基合金。

图形概要