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采用离心铸造方法制备了不同Si、Mg含量的Al-xSi-yMg复合材料筒状铸件,考察了不同成分铸件的宏观组织和微观组织,并测试了不同成分铸件的耐磨性能,分析并计算了Al-xSi-yMg合金中形成初晶颗粒的条件。结果表明:除Al-15Si-5Mg外,其他各成分铸件内侧均形成了含有初晶Si或Mg2Si颗粒的增强层,外侧为不含颗粒的非增强层。不同成分Al-xSi-yMg铸件中形成的初晶颗粒、颗粒增强层的相对厚度值(k)以及颗粒的体积分数各不相同。随着铸件内层初晶颗粒体积分数的逐渐增加,材料的耐磨性能显著提高。计算结果表明,当x≥12.8+0.49y且y≥5时(15≤x≤30,y≤8),合金中形成初晶Si、Mg2Si两种颗粒;当x<12.8+0.49y且y≥5时,合金中只形成初晶Mg2Si颗粒;当x≥12.8+0.49y且y<5时,合金中只形成初晶Si颗粒;当x<12.8+0.49y且y<5时,合金中不形成初晶颗粒。
The microstructure and microstructure of Al-xSi-yMg composites with different contents of Si and Mg were prepared by centrifugal casting method. The wear resistance of castings with different compositions were tested. Al-xSi-yMg alloy to form primary crystal particles. The results show that, except for Al-15Si-5Mg, the reinforcing layer containing primary Si or Mg2Si particles is formed on the inner side of the other castings, and the non-reinforced non-reinforced layer on the outer side. The primary crystal grain formed in the Al-xSi-yMg castings of different compositions, the relative thickness value (k) of the particle reinforced layer, and the volume fraction of the particles vary. With the gradual increase of the volume fraction of primary crystal particles in the inner part of the casting, the wear resistance of the material can be significantly improved. The calculated results show that primary particles of Si and Mg2Si are formed in the alloy when x≥12.8 + 0.49y and y≥5 (15≤x≤30, y≤8). When x <12.8 + 0.49y and y≥ 5, only the primary crystal Mg2Si particles were formed in the alloy; only the primary Si particles were formed in the alloy when x≥12.8 + 0.49y and y <5; when x <12.8 + 0.49y and y <5, Formation of primary crystal particles.