机械搅拌法制备颗粒增强铝基复合材料组织及性能研究

A study on the microstructure and properties of particle-reinforced aluminum matrix composites prepared with mechanical stirring method

采用机械搅拌铸造法制备SiC_(p)/AlSi7Mg0.3铝基复合材料,通过金相组织观察(OM)、扫描电镜(SEM)、XRD等测试方法对SiC增强颗粒的预处理效果、铝基复合材料的显微组织及其力学性能进行研究。结果表明,高温氧化预处理工艺能够改善增强颗粒表面属性,促进Al熔体对颗粒的润湿,最佳高温氧化预处理工艺为1200℃、4 h。随着机械搅拌速度和搅拌时间的增加,SiC颗粒在基体合金中的分布越来越均匀,当搅拌速度达到1200 r/min,搅拌时间为40 min时,SiC颗粒在基体中能够完全均匀分散,且被铝基体润湿,周围无孔洞缺陷存在。所制备的铝基复合材料铸态下抗拉强度达到207.7 MPa,屈服强度达到158.7 MPa,断后伸长率达到1.17%,布氏硬度达到119 HBW,其铸态下强度比ZAlSi7Mg合金材料提升了33%。

SiC_(p)/AlSi7Mg0.3 aluminum matrix composite is prepared with mechanical stirring casting method.The effect of SiC reinforced particle pretreatment,microstructure and mechanical properties of Al-based composite are studied by means of OM(optical microscope),SEM(scanning electron microscope)and XRD(X-ray diffraction).Test results show that the high temperature oxidation pretreatment process can improve the properties of particle-reinforced surface and promote the wetting of particles by Al melt.The optimal high temperature oxidation pretreatment process is 1200℃ for 4 h.With the increase of mechanical stirring speed and stirring time,the distribution of SiC particles in the matrix alloy becomes more and more uniform.When the stirring speed reaches 1200 r/min and the stirring time is up to 40 min,the SiC particles can be completely and uniformly dispersed in the matrix,and can be moistened by the aluminum matrix without any defective holes around.The prepared as-cast aluminum matrix composite can achieve a tensile strength of 207.7 MPa,a yield strength of 158.7 MPa,1.17%elongation after breaking,and a Brinell hardness of 119 HBW,which increases the strength of the as-cast aluminum matrix composite by 33%compared with ZAlSi7Mg alloy material.