Effect of Graphite Addition on the Microstructure and Mechanical Properties of Hot-pressed Titanium Carbide

Abstract

Titanium carbide with a wide range of grain size was consolidated by controlling hot-pressing temperature and small amount of graphite addition. In the TiC without graphite addition, increase in hot-pressing temperature from 2073 to 2373K resulted in the significant grain growth in the sintered body from 7.0 to 27.7μm, which caused decrease in flexural strength from 670 to 430MPa. Graphite addition to TiC caused a distinct inhibition of grain growth resulting increase in flexural strength. Increase in grain size caused increase in fracture toughness of the hot-pressed TiC with and without graphite addition, which may be resulted from increase in traction of fracture surface behind the crack tip. Graphite addition increased in fracture toughness of the TiC due to certain toughening mechanisms such as crack deflection and bridging.