Effect of Graphite as Forming Additive on Wear Properties of (SiCp + Al2O3f)/Al Composites Prepared by Pressure Infiltration

The 2024Al matrix composites reinforced by 30 vol% SiCp and 10 vol% Al2O3f as wear-resistant materials are prepared by pressure infiltration. The graphite powders are added during the preparation of the preform to support shaping. In this article, the effect of the size of the graphite powder on the friction and wear properties of the composites is researched. The results showed that at a given conditions, namely, the size of the SiCp is 14 µm and the diameter of the Al2O3 fiber is 4–5 µm, the composites made from 5 ∼ 30 µm have a more stable friction coefficience and lower wear rate than those from 30 ∼ 50 µm and 50 ∼ 70 µm graphite because the diameter of the generated pores in the corresponding preforms is smaller and more concentrated, resulting in a uniform distribution of the reinforcements in the matrix. The detailed effect mechanisms of different graphite sizes on wear and friction properties of the composites as well as the porosity of the corresponding preforms are also discussed.