T6热处理对SiCp/Al复合材料摩擦磨损性能的影响

采用粉末冶金法制备出不同SiC颗粒体积分数(30%、35%和40%)的SiCp/Al复合材料。采用MMU-5GA微机控制真空高温摩擦磨损试验机对比研究SiCp/Al复合材料在不同体积分数以及T6热处理前后情况下平均摩擦因数和磨损率的变化,通过扫描电镜分析了SiCp/Al复合材料表面磨损形貌,探讨了摩擦磨损机理。试验结果表明,SiC颗粒体积分数在30%~40%变化时,随其体积分数增加耐磨性下降。SiC颗粒体积分数在30%~35%范围内,SiC颗粒与基体结合较好,SiC颗粒作为硬质点起到抵抗磨损和限制基体合金塑性变形产生磨损的双重作用;但SiC含量过多时,颗粒与基体的结合不紧密,磨损时颗粒极易脱落,复合材料耐磨性降低;T6热处理后复合材料的平均摩擦因数和磨损率均降低,这是由于热处理后试样强度及硬度提高,从而提高了试样的耐磨性;常温下复合材料在磨损初期的磨损机理主要以磨粒磨损为主,而在磨损期则为磨粒磨损与剥落磨损共存。

Effect of T6 heat treatment on friction and wear properties of SiCp/Al composites

SiCp/Al composites with different Si C particle volume fractions(30%,35%and 40%)were prepared by means of powder metallurgy.The changes of average friction coefficient and wear rate of SiCp/Al composites under different volume fraction and T6 heat treatment were studied by using MMU-5 GA microprocessor controlled high temperature friction and wear tester.The wear morphology of SiCp/Al composites was analyzed by means of scanning electron microscopy,and the friction and wear mechanism was discussed.The results show that when the volume fraction of Si C particles varies from 30%to 40%,the wear resistance decreases with the increase of the volume fraction.In a certain range of 30%-35%Si C particle volume fraction,Si C particles bond well with the matrix,as a hard point,Si C particles play a dual role in resisting wear and restricting the plastic deformation and wear of the matrix alloy.However,when the Si C content is too high,the bonding between the particles and the matrix is not close,the particles are easy to fall off during wear,and the wear resistance of the composites decreases.The average friction coefficient and wear rate of the composite decrease after heat treatment,because the strength and hardness of the sample after heat treatment are improved,so does the wear resistance of the sample.At room temperature,the wear mechanism of composites is mainly abrasive wear at the early stage of wear and abrasive wear and peeling wear coexist at the wear stage.