Rare earth (RE) can produce excellent precipitation hardening in Mg alloys. However, when forming a solid solution, it also deteriorates formability, a problem that can usually be overcome by raising deformation temperature. Here we report an unexpected observation of high temperature brittleness in a Mg-Gd-Y-Ag alloy. As the temperature reached 500 °C, the formability decreased drastically, leading to severe intergranular fracture under only 0.5% strain. This was caused by failure of grain boundaries, which are weakened by segregated interfacial compounds.

中文翻译：

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Mg-Gd-Y-Ag 合金的意外高温脆性

稀土 (RE) 可以在镁合金中产生出色的沉淀硬化。然而，当形成固溶体时，它也会降低成型性，这个问题通常可以通过提高变形温度来克服。在这里，我们报告了对 Mg-Gd-Y-Ag 合金高温脆性的意外观察。随着温度达到 500 ℃，成形性急剧下降，仅在 0.5% 应变下导致严重的沿晶断裂。这是由晶界失效引起的，晶界被偏析的界面化合物削弱。