Abstract

The effect of 0.25 wt% and 0.5 wt% rare earth Er addition on the microstructure and creep behavior of the cast A356 alloy was investigated. The microstructure of the alloys before and after the creep was evaluated by optical and scanning electron microscopy equipped with energy dispersive spectrometry. The creep behavior was examined by the impression creep test at the temperature range of 493 to 553 K under the stresses between 480 and 680 MPa. Results showed that the addition of Er addition caused the α-Al dendrites to refine and the morphology of the eutectic silicon to modify significantly. The microstructure of the A356 alloy with Er addition was characterized by Er-rich intermetallics. The lattice self-diffusion climb-controlled creep was found to be the dominant creep mechanism in all alloys. The addition of Er improved the creep resistance of the A356 alloy and the alloy modified with 0.5 wt% Er exhibited the highest creep resistance.

Graphic Abstract

中文翻译：

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稀土Er对Al-7Si-0.3Mg合金组织和蠕变行为的影响

摘要

研究了 0.25 wt% 和 0.5 wt% 稀土 Er 添加对铸造 A356 合金的显微组织和蠕变行为的影响。通过配备能谱仪的光学和扫描电子显微镜评估蠕变前后合金的微观结构。在 480 至 680 MPa 的应力下，在 493 至 553 K 的温度范围内通过压痕蠕变试验检查蠕变行为。结果表明，Er的加入使α-Al枝晶细化，共晶硅的形貌发生显着改变。添加 Er 的 A356 合金的微观结构以富含 Er 的金属间化合物为特征。发现晶格自扩散爬升控制蠕变是所有合金中的主要蠕变机制。

图形摘要