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采用普通重力铸造、挤压铸造和等温热处理半固态挤压的方法制备了原位Mg2Si/Al复合材料,研究了其组织演变和耐磨性.结果表明,P孕育变质后,铸态组织中Mg2Si增强相由粗大的枝晶转变为细小的块状,经过等温热处理后的半固态组织,Mg2Si增强相分布均匀、尺寸细小,表现为规则的球形,a-Al的形貌也变得较为圆整,表现为规则的球状或椭球状.此外,等温热处理的半固态组织中的Mg2Si和a-Al尺寸还有较为明显的改变.与普通重力铸造Mg2Si/Al复合材料相比,挤压铸造复合材料的HB硬度提高了23.5%,半固态挤压复合材料的HB硬度提高了39%.在相同磨粒尺寸和载荷条件下,普通重力铸造复合材料的磨损率最大,挤压铸造复合材料的磨损率次之,半固态挤压复合材料的磨损率最小.
In-situ Mg2Si / Al composites were prepared by ordinary gravity casting, squeeze casting and isothermal heat treatment of semi-solid extrusion.The microstructure evolution and wear resistance of the composites were studied.The results show that after the P gerthenization, the as-cast microstructure The Mg2Si phase is transformed from coarse dendrites into fine blocks. After being isothermally heat treated, the microstructure of Mg2Si reinforced microstructure is uniform and small in size, showing a regular spherical shape. The morphology of a-Al also changes More round, the performance of the rules of spherical or ellipsoidal.In addition, the isothermal heat treatment of semi-solid Mg2Si and a-Al size there is a more significant change compared with the ordinary gravity casting Mg2Si / Al composite material , The HB hardness of the die-cast composite increases by 23.5% and the HB hardness of the semi-solid extruded composite increases by 39% .At the same abrasive size and loading conditions, the wear rate of ordinary gravity casting composites is the largest, The wear rate of the cast composite was second, and the wear rate of the semi-solid extruded composite was the lowest.