Investigation on microstructure and reinforcement mechanism of the TiC-reinforced W-matrix composite prepared by high-energy ball milling and spark plasma sintering

Abstract

The W–TiC composite with low density and good mechanical properties was prepared by high-energy ball milling and spark plasma sintering. The microstructure morphology and phase composition of the W–TiC composite were investigated. The characteristics of the interface between the second phases and the matrix were calculated and analyzed. The addition of TiC reinforcing phase significantly inhibited the growth of W grains. The reinforcing phase was distributed in long stripes in the W–TiC composite, and a variety of second phases existed in the W–TiC composite such as TiC, Ti, and W2C. First-principles calculations of three heterostructure interfaces (W–TiC, W–Ti, W–W2C) showed that the phases of W2C and Ti play a crucial role in improving interface stability and interfacial strength. The grain refinement effect and the second phase strengthening effect make the average microhardness of the W–TiC composite reach ∼958 HV, and the compressive strength at room temperature and high temperature (600 °C) are ∼2374 MPa and ∼1884 MPa, respectively. Although the compressive strength of the W–TiC composite at high temperature is ∼20.7 % lower than that at room temperature, it still shows certain thermal stability and sufficient mechanical properties.