Microstructure and mechanical properties of TiC-10Mo-20Ni cermets

Abstract

TiC-10Mo-20Ni cermets with outstanding comprehensive properties were fabricated using Ni powder, self-synthesized ultrafine TiC and Mo powders. The effects of different liquid-phase sintering temperatures (1450–1525 °C) on the microstructure and mechanical properties of TiC-10Mo-20Ni cermets were investigated. The results demonstrated that all sintered samples exhibited a uniformly distributed core-rim structure. As the temperature increased, the degree of densification increased, and the number of gray coreless grains increased. The grain size of TiC-10Mo-20Ni cermets gradually increased with temperature, with the average grain size rising from 1.04 ± 0.29 μm to 1.43 ± 0.55 μm. The hardness of the sintered samples initially increased and then decreased with temperature, reaching a peak value of 1622 HV₃₀ at 1475 °C. The fracture toughness (K_IC) and transverse rupture strength (TRS) increased with temperature, and had the values of 15.02 MPa·m^1/2 and 1741 MPa at 1525 °C, respectively. The sintered samples were mainly dominated by a mixed fracture pattern of intergranular fracture and transgranular fracture, with transgranular fracture increasing as the temperature rose. Meanwhile, the crack extension and fracture morphology became more intricate, thus enhancing the K_IC and TRS.