Research on the Properties of Boron Carbide Particle-Reinforced Copper-Matrix/Graphite Self-Lubricating Composite Materials

Abstract

Graphite particles and boron carbide (B₄C) particles were added into copper matrix composites by powder metallurgy to form a new composite-reinforced and lubricated system. The effects of different amounts of B₄C particles on the properties of composites were studied. With addition of 2 wt % graphite powder as the solid lubricating phase, the effects of B₄C particle content on the microstructure, density, porosity, Vickers hardness, compressive strength, and the friction and wear properties of the copper-matrix/graphite self-lubricating composite materials were investigated. The results indicate that increasing addition of B₄C particles significantly improved the density, Vickers hardness, compression strength; friction and wear properties of composites. However, excess B₄C particles also increased porosity. The connected netted B₄C particles disrupt the continuity of the metal matrix causing serious decreases in density, Vickers hardness, compression, and the friction and wear properties of the composite material. Of the tested composites, the materials containing 1.5 wt % B₄C showed the best friction and wear resistance properties.