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采用原位反应法制备了20%Mg_2Si/Al基复合材料,研究了过剩Si含量对该复合材料显微组织和硬度的影响。结果表明:未添加过剩Si时,复合材料中的初晶Mg_2Si相呈现出粗大的树枝晶和多边形块状,其硬度值最低约为82 HB;当过剩Si含量为5%时,初晶Mg_2Si相的尺寸最为细小,复合材料的硬度值增加至93 HB;当过剩Si含量为8%时,初晶Mg_2Si相的晶粒粗化,α-Al相球化,复合材料的硬度达到最大,约为108 HB,提高了31.7%。
The in-situ reaction method was used to prepare 20% Mg 2 Si / Al matrix composites. The effects of excess Si content on the microstructure and hardness of the composites were investigated. The results show that when the excess Si is not added, the primary Mg_2Si phase in the composites shows coarse dendrites and polygons with the lowest hardness value of about 82 HB. When the excess Si content is 5%, the primary Mg_2Si phase The hardness of the composites increases to 93 HB. When the content of excess Si is 8%, the grains of the primary crystal Mg 2 Si are coarsening and the α-Al phase is spheroidized, the hardness of the composite reaches the maximum, which is about 108 HB, an increase of 31.7%.