Study on the Microstructure and Mechanical Properties of TiB2-Ti(C,N) Composite Ceramic Tool Materials

Abstract

TiB2-Ti(C, N)-(Ni, Mo) composite ceramic tool materials were fabricated by the hot-press sintering technology. The effects of the content of Ti(C, N) on the microstructure and mechanical properties were investigated by XRD and SEM observations. It is shown that the grain size of the composites is small, the fracture surface is irregularity, the grain boundaries of TiB2 and Ti(C, N) are connected tightly, and a new crystalline phase of MoNi is formed. A small amount of Ti(C, N) is decomposed into TiN, and the decomposition of Ti(C, N) is intensified as the content of Ti(C, N) is increased during the sintering process. The fracture pattern is the combination of the intergranular mode and transgranular mode. It is found that the flexural strength and fracture toughness of TiB2-Ti(C, N)-(Ni, Mo) composites increase consistently owning to the addition of Ti(C, N), the maximum resultant mechanical properties of TiB2-Ti(C, N)-(Ni, Mo) composites are 1019.53MPa for the flexural strength, 6.89MPa•m1/2 for the fracture toughness and 23.65GPa for Vickers hardness.