Electrical wear of TiB2 particle-reinforced Cu and Cu–Cr composites prepared by vacuum arc melting

Abstract In this paper, TiB2 particle-reinforced Cu and Cu–Cr composites were prepared by the vacuum arc melting technique. The tensile strength, electrical conductivity and wear properties of the composites were tested. The microstructure and wear morphology of the composites were characterized by SEM. The results showed that microscale TiB2 particles were dispersed uniformly in copper matrix, and the interface between the TiB2 particles and matrix was clean and well bonded. Nanoscale Cr particles were dispersed in the copper matrix. The friction coefficient and wear rate of the composites increased with increasing current. The dual-scale TiB2/Cu–Cr composites with nanoscale Cr particles and microscale TiB2 particles possessed a high strength and hardness, that was conducive to improving the wear resistance. Compared with the wear rate for composites prepared with powder metallurgy, when the current was 50 A, the wear rate of TiB2 particle-reinforced Cu and Cu–Cr composites prepared by vacuum arc melting decreased by 9.3% and 55.3%, respectively. The Cr particles strengthened the copper matrix and the TiB2 particles supported the friction process. The synergistic effect improved electrical wear resistance of the TiB2/Cu–Cr composite. Microstructural observations revealed that the main wear mechanisms of the composites were adhesive wear, abrasive wear and arc erosion.