In-situ synthesized TiC particle-reinforced titanium matrix composites prepared by gas-solid reaction

Using hydrogenation-dehydrogenation titanium powders as the raw materials, the in-situ synthesized TiC particles were prepared by gassolid reaction at a certain temperature under the atmosphere of CH4 after cold isostatic pressing, then the TiC particle-reinforced titanium matrix composites were manufactured by vacuum sintering with the oxygen content (volume fraction) less than 0.2%.In the results, the volume fraction of TiC particles can be controlled by adjusting the temperature and time of gassolid reaction, and the TiC particle-reinforced titanium matrix composites with the higher volume fraction of TiC particles (> 30%) can be obtained.TiC is first formed on the surface of titanium powders, and the growth of TiC particles is obviously hindered by Ti powders, resulting in the grain refining of TiC particles; however, the excessive TiC particles also hinder the self-diffusion process of titanium in the sintering process and reduce the relative density.The titanium powder compacts handled by gassolid reaction at 700 ℃ under the atmosphere of CH4 for 30 min are vacuum sintered at 1300 ℃, and the sintered specimens show the better comprehensive mechanical properties, the tensile strength is 606 MPa, the elongation is 14.4%, the hardness is HV 442, and the relative density is 98.6%.However, a relatively short period of gassolid reaction cannot guarantee the uniform distribution of TiC particles, resulting in the inhomogeneity in the internal and external structures of sintered specimens.