Effects of Si on friction properties of Ti₃SiC₂/Al composites

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 Ti₃SiC₂ powder as raw materials, the study prepared Ti₃SiC₂ reinforced Al-Si-base composites in the way of cold briquetting and pressure-free sintering. It is found that apart from Al, Si and Ti₃SiC₂ phases, Al₂O₃ and Al4C3are produced in the process of sintering. With the increase of silicon content, large spherical Ti₃SiC₂ gradually reduces. And the friction coefficient and wear weight first decrease and then increase. When the silicon content (mass fraction) is 12.5 %, the friction coefficient is at its lowest of 0.18, 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.