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研究了含有不同第二相的金属型铸造Mg-Ca-Sn镁合金的显微组织和力学性能。结果表明:在合金中Ca和Sn单独存在可以在一定程度抑制铸态基体晶粒长大,Mg2Ca在晶界或枝晶界处连续分布,Mg2Sn呈颗粒状在晶界和晶内分布。Ca和Sn同时存在时,有CaMgSn在基体上呈半连续的点状或针状,在凝固过程中可作为α-Mg的异质形核核心,与单独添加相比,镁基体的铸态晶粒尺寸显著细化。运用边-边匹配模型分析了CaMgSn化合物与α-Mg之间的异质形核晶体学关系。晶粒细化后的Mg-Ca-Sn镁合金的显微硬度得到明显提高。
The microstructure and mechanical properties of Mg-Ca-Sn magnesium alloy with different secondary phases were studied. The results show that the presence of Ca and Sn in the alloy can restrain the grain growth of the as-cast matrix to a certain extent, the distribution of Mg2Ca continuously in the grain boundary or dendritic boundaries, and the distribution of Mg2Sn in the grain boundaries and grains. In the presence of Ca and Sn, CaMgSn is semi-continuous dot or needle on the matrix and can be used as heterogeneous nucleation sites of α-Mg during solidification. Compared with the addition of CaMgSn alone, Significant grain size refinement. Edge-edge matching model was used to analyze the heterogeneous nuclear crystallography relationship between CaMgSn and α-Mg. After the grain refinement of the Mg-Ca-Sn magnesium alloy hardness was significantly improved.