Effect of sintering temperature on microstructure and tribological properties of copper/graphite composites doped with Ti3AlC2 particles

Abstract

Copper/graphite composites have received much attention in engineering applications due to their excellent thermal, electrical and self-lubricating properties. However, their mechanical and wear resistance properties are usually limited by the brittleness of graphite and the poor interfacial bond between graphite and copper. Harder particles can be used to reinforce composites to increase their mechanical properties and wear resistance. In this paper, copper/graphite composites added with Ti3AlC2 particles were prepared by rapid hot press sintering. Studies were conducted to find out how the sintering temperature affected the composites' phase composition, morphology, hardness, relative density, and friction properties. The results showed that the relative density and hardness of the composites increased and then decreased with increasing sintering temperature. Besides, the findings indicated that Al atoms started to diffuse out of Ti3AlC2 and into the Cu matrix around 800 °C, leading to the in-situ formation of TiCx and Cu(Al) alloys. When the sintering temperature exceeded 850 °C, Ti3AlC2 decomposed essentially completely. In comparison to other similar prior findings (the wear rate was ∼1 ×10−4 mm3·N−1·m−1), the copper/graphite composites prepared in this work shown improved wear resistance. Among them, the lowest wear rate (1.942 × 10−5 mm3·N−1·m−1) was obtained at a sintering temperature of 900 °C, with a relative density of 98.41%, a hardness of 75.67 HV and an average coefficient of friction of 0.15. This will help to further broaden the application areas of copper/graphite composites.