Effect of TiC content on mechanical and tribological properties of TiC/Cu composites prepared by SPS

Abstract

Copper matrix composites reinforced with different mass fractions of TiC particles were prepared by spark plasma sintering （SPS） technology. The microstructures of the copper matrix composites with different sintering temperatures and TiC contents were investigated. The effects of TiC content on the electrical conductivity， nano-mechanical properties， microhardness， tensile properties， and tribological behaviors of the composites were studied. Results show that the TiC/Cu composites obtained by sintering at 850 ℃ have a dense structure， with a good bonding between the reinforcements and the matrix. On the one hand， as the TiC content increases， the grains of the copper matrix phase in the TiC/Cu composites are continuously refined and the grain boundary density increases. This leads to an increase in the hardness and yield strength of the composites. On the other hand， the increase in TiC content gradually leads to the development of pores and cracks at the bonding interface between the reinforcement and matrix. When bearing or transmitting load， the pores and cracks will become the preferred location for stress concentration and crack formation， resulting in a reduction in the conductivity， tensile strength， and elongation of the composite. With TiC content of 5%-15%（mass fraction，the same below）， the composites have higher tensile strength， modulus of elasticity and yield strength， appropriate hardness， and better overall mechanical properties. When the TiC content exceeds 20%， the yield strength of TiC/Cu composites decreases significantly and the composite fracture mechanism changes from ductile fracture to brittle fracture. The TiC reinforcements significantly improve the tribological properties of the copper matrix composites. The friction coefficient and wear of the composites during friction increase linearly with increasing load and tend to decrease with increasing TiC content. At a TiC content of 20%， the composite has the highest wear resistance and lowest coefficient of friction. The wear mechanism is dominated by abrasive wear， accompanied by slight adhesive wear and oxidative wear.

Keywords

• copper matrix composites
• spark plasma sintering
• microstructure
• mechanical property
• tribological behavior