Effect of surface roughness on tribological properties of TiB2/Al composites

•55 vol.% TiB2/2024Al composites are fabricated by pressure infiltration method.•Effect of surface roughness on tribological properties are investigated.•Optimal roughness is determined by combining microstructure and wear mechanism.

55 vol.% TiB2/2024Al composites were fabricated by pressure infiltration method. The effect of surface roughness of GCr15 steel disc (Ra 0.606, 0.372, 0.023, 0.005 μm) on the tribological properties of composites was investigated. Results showed that with the change of surface roughness, there is an optimal value (Ra 0.023 μm) under which the friction coefficient and wear rate is the lowest. The optimal surface roughness is in the same order of mixture of TiO2 and B2O3, observed on the surface of TiB2 particles after pre-heating process. During sliding, the filling of this oxidation layer into the asperity gap of GCr15 and greatly reduces adhesion between aluminium and GCr15, furthermore, decreases the friction coefficient and wear rate.