Microstructure and tribological properties of copper/graphite composites with Ti3AlC2 addition prepared by rapid hot press sintering

Abstract

Copper/graphite composites are widely used due to their excellent electrical, thermal, and self-lubricating properties. However, their mechanical and anti-wear properties are usually limited by brittle graphite and soft copper matrix. Enhancing the properties of composites by further introducing harder ceramic particles is an effective way. However, these particles are usually poorly wetted to metal and can easily separate from the matrix during friction, causing more severe abrasive wear. Herein, TiCx-reinforced Cu/graphite composites were prepared by rapid hot press sintering of a hybrid powder consisting of Ti3AlC2, Cu-plated graphite, and Cu powder. Al atoms diffused out of Ti3AlC2 and solid-solved into the Cu matrix during the sintering process, forming TiCx and Cu(Al) alloys. Such in situ formed TiCx particles have good interfacial bonding with the matrix. With the increase of Ti3AlC2 addition from 0 to 15 wt%, the average grain size of the composites decreased, the relative density increased, the hardness became larger, the electrical conductivity decreased, and the average coefficient of friction were all maintained at about 0.14, but the wear rate was reduced from 3.6569 × 10−4 mm3·N−1·m−1 to 9.35013 × 10−6 mm3·N−1·m−1. The in situ Ti3AlC2-derived TiCx particles improved the deformation resistance and shear resistance of the Cu/graphite composites, thus contributing to the wear resistance. This research may offer fresh perspectives on how to enhance the properties of copper/graphite composites.