Effect of SPS process sintering on the microstructure and mechanical properties of nanocrystalline TiC for tools application

The most important spark plasma sintering (SPS) parameters (Temperature, holding time and pressure), have been reviewed to assess their effect on the densification, grain growth kinetics and mechanical properties of nanocrystalline TiC synthesized by mechanical alloying. Experiments were performed in the 1350–1800 °C temperature range with holding time from 1 to 10 min under various pressure values of 50, 80 and 100 MPa. The results of experiments revealed that the mechanical properties of the material were improved with raising the sintering temperature and extending the sintering time. However, a hardness decrease was observed as a result of abnormal grain growth under higher sintering temperatures. The optimized process parameters for SPS process are identified as a sintering temperature of 1650 °C, a pressure 100 MPa and a sintering time of 5 min. The resulting mechanical properties are: a relative density of 97.9%, a micro-hardness of 2570 Hv, a nano-hardness of 28 GPa, a fracture toughness of 4.9 MPa·m1/2 and a compressive strength of about 2210 MPa.

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► The Bottom-up strategy combining mechanical alloying and SPS is a powerful process to obtain TiC materials denser.
► The obtained materials present very high compressive strength of about 2210 MPa and a nano-hardness of 28 GPa.
► The improvement in fracture toughness was attributed to crack bridging and crack deflection.