LI Shaofeng
(Ningbo Donglian Seals Co., LTD., Ningbo 315191, Zhejiang, China)
Abstract: Titanium carbide (TiC) composites were fabricated by using hot pressing sintering process. The fracture morphology and apparent morphology were observed by using scanning electron microscopy (SEM). Mechanical properties of the samples were evaluated. X-ray diffraction (XRD) was used to characterize the phase composition of the composites. The oxidation behavior of the samples was also discussed. The microstructure and mechanical properties of the titanium carbide materials were improved due to the addition of WC. The discrete reinforcing of WC particles in the TiC matrix and the strengthening and toughening of metal components contributed to the improvement in comprehensive properties of the TiC composites. The sample S4 with 15 wt.% WC had the optimized performance, owing to the synergistic effect of the metal phase malleabled and the carbide hard phase dispersed in the matrix, with hardness of 21.7 GPa, bending strength of 1139 MPa, fracture toughness of 9.8 MPa•m1/2 and relative density of 99.2%. Under the oxidation conditions at 1150 ℃ for 2 h, a relatively dense oxide layer was formed on the surface of the samples. The layer thicknesses of the oxidation layer and the transitional layer are about 52.3 μm and 22.8 μm, respectively.
Key words: titanium carbide; composites; hot pressing sintering; oxidation resistance