SiC粒径比对SiC_p/Al基复合材料组织及性能的影响

采用高压扭转(high pressure torsion)法将粒径比分别为1:1,1:7,1:21的SiC颗粒和纯铝粉末的混合物固结成金属基复合材料。利用金相显微镜、显微维氏硬度计、万能试验机和扫描电镜研究不同SiC粒径比对SiCp/Al复合材料显微组织和力学性能的影响。结果表明,与SiC粒径比1:1的试样相比,粒径比为1:7和1:21的试样中SiC颗粒分布更加均匀,颗粒间无明显团聚现象;大颗粒加入后对材料硬度的影响较为复杂,1:21试样硬度值最低;材料伸长率分别提高130%和113%,致密度也高于1:1的试样,材料断裂形式为韧性断裂。SiC粒径比为1:7试样的致密度、伸长率高于粒径比为1:21试样,综合性能较好。

Effects of SiC particle size ratio on microstructure and mechanical properties of SiCp/Al composites

The mixtures of SiC particles with different particle size ratio of 1:1, 1:7, 1:21 and pure Al powder were fabricated into metal matrix composites by high pressure torsion (HPT). The effects of different particle size ratio on the microstructure and mechanical properties of the composites were investigated by optical microscope, microhardness- testing device, universal testing machine and scanning electron microscope. The results show that when the particle size ratios are 1:7 and 1:21, the distribution of SiC particles is more uniform, and there is no obvious agglomeration. The effect of large particles on the hardness is more complex, and the microhardness of sample with particle size ratio of 1:21 is the lowest. The elongation of the samples have increased by 130% and 113% respectively, compared to the sample with particle size ratio of 1:1. The density is also higher than that of the sample with particle size ratio of 1:1, and the fracture manner of the two materials is ductile. When the particle size ratio is 1:7, the composite has better performance, and the density and elongation are higher than those of the sample with particle size ratio of 1:21.