In-situ development of Ti(C, N) and their effect on microstructure,wear and corrosion properties of CoCrFeNiTi high-entropy alloy matrix composites

In situ Ti(C, N) reinforced high-entropy alloy (HEA) matrix composites were fabricated spark plasma sintering (SPS). The effects of Ti(C, N) on the microstructure, wear and corrosion behaviour of the composites were systematically investigated in this study. The Ti(C, N) particles were uniformly distributed and well bonded to the HEA interface. Hardness analysis revealed that the addition of Ti(C, N) significantly increased the hardness of the composites from 776Hv to 1256.3Hv. Additionally, when Ti(C, N) was incorporated, the wear mechanisms of High Entropy Alloys (HEA) changed from adhesive wear, oxidative wear, and delamination to abrasive and oxidative wear. The Ti(C, N)/HEA composite showed the highest nano-hardness, resulting in the wear rate of the composites was significantly lower than that of the HEA. In H2SO4 solution, pitting corrosion mainly occurs in HEA. However, the introduction of Ti(C, N) resulted in finer grains and the formation of a denser and more stable passivation film on the composite surface. This inhibited pitting, leading to lower corrosion current density and higher polarization impedance compared to HEA Alloy.