Magnesium alloys containing rare earth metals exhibit good creep resistance up to 300 °C and good tensile properties at ambient temperature. The high cost of rare earth has led to studies regarding the creep resistance of Mg alloys with cheap alloying elements (Sn, Ca, Si) that could be substituted for Mg-RE alloys. In this paper, the influence of Si and Al on microstructure and mechanical properties of Mg-7Sn alloy was investigated using optical (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), tensile tests and creep tests at 200–250 °C. Microstructure of as-cast alloys consists of α-Mg matrix and intermetallic compounds at the interdendritic regions. Heat treatment consisting of solid solution treatment and ageing increases the tensile properties at ambient temperature due to the precipitation of the fine Mg₂Sn phase. The creep resistance of aged Mg-7Sn alloy is poor. The addition of Si and Al to Mg-7Sn alloy has resulted in improving the creep resistance due to the refinement of Mg₂Sn phase and the appearance of Mg₂Si phase at the grain boundaries. The Mg-7Sn-1Si alloy exhibits better creep resistance at 200 °C than Mg-7Sn-5Si and Mg-7Sn-5Si-2Al alloys. The Mg-7Sn alloys with 5% Si have better creep properties at 250 °C in comparison to Mg-7Sn-1Si alloy.

中文翻译：

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铸造Mg-Sn-Si-（Al）镁合金的组织和蠕变性能

包含稀土金属的镁合金在300°C的温度下仍具有良好的抗蠕变性，并且在环境温度下具有良好的拉伸性能。稀土的高成本导致人们开始研究具有可替代Mg-RE合金的廉价合金元素（Sn，Ca，Si）的Mg合金的抗蠕变性。本文采用光学（LM），扫描电子显微镜（SEM），透射电子显微镜（TEM），X射线衍射分析（XRD）研究了Si和Al对Mg-7Sn合金组织和力学性能的影响。 ，拉伸试验和蠕变试验在200–250°C下进行。铸态合金的显微组织由枝晶间区域的α-Mg基体和金属间化合物组成。₂ Sn相。时效的Mg-7Sn合金的耐蠕变性差。在Mg-7Sn合金中添加Si和Al，由于Mg ₂ Sn相的细化和晶界处Mg ₂ Si相的出现，提高了抗蠕变性。Mg-7Sn-1Si合金在200°C时比Mg-7Sn-5Si和Mg-7Sn-5Si-2Al合金具有更好的抗蠕变性。与Mg-7Sn-1Si合金相比，含5％Si的Mg-7Sn合金在250°C时具有更好的蠕变性能。