Si对Ti_3SiC_2/Al复合材料的摩擦性能影响

Effects of Si on friction properties of Ti_3SiC_2/Al composites

MAX相因其独特的晶体结构和优良的自润滑性能受到广泛的关注,作为新型固体润滑剂添加到金属基复合材料可获得良好的摩擦磨损性能.采用铝粉、硅粉、Ti_3SiC_2粉为原材料,通过冷压成型无压烧结法制备了Ti_3SiC_2增强铝硅基复合材料.研究发现,复合材料的组成物相除Al、Si及外加Ti_3SiC_2相之外,在烧结的过程中生成了Al_2O_3和Al_4C_3.随着硅元素含量质量分数的增加,大的圆球形Ti_3SiC_2逐渐减小,摩擦系数和磨损失重均呈现先减小后增大的规律.当硅的含量为12.5%时,摩擦系数最低,其值为0.18,磨损失重也达最低;随着硅含量的增加,材料的硬度先增大后趋于平缓,致密度呈线性下降趋势.通过磨损表面SEM分析初步揭示了金属基自润滑的机理,复合材料的磨损机制为磨粒磨损、剥层磨损和氧化磨损并存.

MAX phase has obtained widespread attention as a result of its unique crystal structure and excellent self-lubricating properties.As a new solid lubricant,when added to the metal matrix composites material,its friction and wear properties can get better.Using aluminum powder,silicon powder and Ti3SiC2powder as raw materials,the study prepared Ti3SiC2reinforced Al-Si-base composites in the way of cold briquetting and pressure-free sintering.It is found that apart from Al,Si and Ti3SiC2phases,Al2O3and Al4C3are produced in the process of sintering.With the increase of silicon content,large spherical Ti3SiC2gradually reduces.And the friction coefficient and wear weight first decrease and then increase.When the silicon content(mass fraction)is12.5%,the friction coefficient is at its lowest of0.18,and the wear weight is also at its lowest.With the increase of silicon content,the hardness of the material first increases and then slowly grows,and its density decreases linearly.The mechanism of metal matrix self-lubricating is revealed by SEM analysis of wear surface.The wear mechanism of the composite material includes abrasive wear,stripping wear and oxidation wear.