Microstructure and Mechanical Properties of TiCN-Ni Based Cermets Strengthened by Fore-Solid Solubilizing Ti in Ni

TiCN-Ni based cermets were prepared by pre-solid solubilizing Ti in Ni to adjust the composition of the binder in advance. The composition, morphology, microstructure and effects on TiCN cermets of Ni-Ti powder were tested and analyzed by XRD, SEM, EDS and TEM. The mechanical properties such as transverse rupture strength, fracture toughness and hardness were tested. The results showed that the wettability of Ni to ceramic particles can be improved, and the particles could be refined by pre-solution treatment. The reasons for the improvement of wettability were as follows: the content of alloy elements in the binder phase during sintering was adjusted, the complete and uniform rim-shaped phase was formed, and a nanometer thickness transition zone was formed between the metal binder phase and the rim-shaped phase. In addition, a high density of dislocation in the transition zone could inhibit grain growth. The fracture mode of cermets was mixed fracture mode composed of intergranular fracture and transgranular fracture. When 3 wt.% Ti was fore-solid solubilized in Ni, the performance of the cermets was the best. The transverse rupture strength, fracture toughness and the hardness of the cermets reached 2356.8 Mpa, 14.33 MPa·m1/2 and 88.9 HRA, respectively.