Mechanical Properties of Titanium Composites Reinforced with Reaction Sintered TiC Prepared By Pulse Electric Current Sintering

Titanium alloys have high strength and excellent corrosion. On the other hand, the wear resistance is inferior. For improve wear resistance, an addition of TiC powder to titanium alloys is effective. However, a large amount of direct TiC powder addition causes to clustering TiC powder and porosities, thereby reducing strength.

In this study, instead of directly adding TiC powder, some other kinds of carbide powder added to titanium powder takes self-generating TiC during sintering. The carbides are VC, ZrC, NbC and Mo₂C selected to commercially obtain and to easily generate TiC during sintering. Pure titanium powder and carbide powder were mixed and sintered by spark plasma sintering. It is assumed that each added carbide in the composites turn to the TiC. The obtained composites are investigated their mechanical properties.

The tensile strength of all composite is increased with an increase in volume fraction of TiC. In case of Mo₂C addition for 3vol.%TiC, tensile strength showed a significant increase compared to the other composites with 3vol.%TiC. Further, of all composites with 15vol%TiC, VC has the most effective.

As the observation of microstructure in the composites, the composite with 3vol.%TiC by adding Mo₂C has a low porosity in spite of adding some Mo₂C. Further, the composite with15vol%TiC by adding VC has a homogeneous distribution of small TiC particles, against TiC particle cluster in the other composite.

The tensile strength depends on the TiC particle distribution and porosity in the composite. The TiC particle distribution is improved by the reaction sintering of the Ti powder and VC or Mo₂C powder instead of directly adding TiC powder.