Effects of the addition of NbC on the performance of copper-based composites by spark plasma sintering

Copper-based composites with different quality scores for NbC particle reinforcement were prepared by spark plasma sintering. The microstructure of the copper-based composites with different NbC contents was studied, and the influence of NbC content on the density, electrical conductivity and hardness of the copper-based composites was investigated. The results showed that the electrical conductivity of the Cu-4 wt% NbC composite material after spark plasma sintering was 70.4% IACS (IACS is the percentage of the ratio of the conductivity of the sample to a certain standard value. The annealed copper wire with a density of 8.89 g cm⁻³, a length of 1 m, a weight of 1 g and a resistance of 0.15328 Ohm is used as this certain standard value), and the hardness was 63.4 HV. The strengthening mechanisms of NbC in copper-based composites were dispersion strengthening and fine crystal strengthening. During the spark plasma sintering process, the Zener pinning of NbC particles slowed grain boundary migration, which effectively prevented the pure copper grains from growing and thus enhanced the pure copper. The proportion of NbC in the raw powder was changed to adjust the proportion of fine crystals, and then the mechanical properties of the material were adjusted. Additionally, NbC caused a preferred orientation of pure copper and reduced some of the stress in the material.