Effect of TiC additions on the microstructure, mechanical and tribological properties of NbC-CoCrFeNiMn high entropy alloys cermets

NbC-xTiC-15CoCrFeNiMn (x = 0, 5, 10, 15) cermets were prepared by powder metallurgy, and the effects of the addition of second-phase carbide TiC on microstructure, mechanical properties and wear resistance of the cermets were systematically investigated. The results showed that the grain growth phenomenon occurred more obviously in the cermets without TiC addition, while the addition of TiC led to effective suppression of grain growth. Meanwhile, TiC additions resulted in significant increases in hardness under fine grain strengthening effect and solid solution strengthening effect. The NbC-10TiC-15CoCrFeNiMn cermet exhibited the highest transverse strength. With adding 15 vol% TiC, the cermets exhibited the highest relative density of 98.0% and the highest hardness of 1471.5 kg/mm(2). Furthermore, the addition of TiC improved wear resistance of the cermets. The adhesive wear was gradually reduced with increasing TiC contents, and NbC-15TiC-15CoCrFeNiMn cermets exhibited the smallest wear depth.