P对原位合成20Mg_2Si/Al-Si复合材料组织与性能的影响

Effects of P Element on Microstructure and Mechanical Properties of 20Mg_2Si/Al-Si Composites

采用原位反应法制备了20Mg_2Si/Al-Si复合材料,研究了P对该复合材料微观组织和力学性能的影响。结果发现,未添加P时,复合材料中的初生Mg_2Si相呈现出粗大的树枝晶和多边形块状;当加入P后,初生Mg_2Si相转变为细小的颗粒状,其实质是P与Al形成了AlP化合物,并充当了初生Mg_2Si相的异质形核核心。未变质时,复合材料的硬度(HB)和抗拉强度约为71.5和102.1 MPa,而加入P后,复合材料的硬度(HB)和抗拉强度分别增加至97.2和133.6 MPa。

The effects of P on the microstructure and mechanical properties of 20Mg2Si/Al-Si composites fabricated by in situ reaction were investigated.The results show that the primary Mg2Si phase in the composites without P addition presents the feature of coars dendrite or polygonal block,while the primary Mg2Si phase is changed from dendrites to fine particles with the addition of P element,which is attributed to the elements Al and P forming a compound of AlP to be acted as heterogeneous nucleation sites.The hardness and tensile strength of the composites without P addition are 71.5 HB and 102.1MPa,respectively,while with adding P element,the hardness and tensile strength of the composites are increased to 97.2HB and 133.6 MPa,respectively.