Microstructure, Mechanical Properties, and Sintering Behavior of Ti₃O-Fe₂TiO₄-TiC Composites

This study aims to assess the impact of TiC content on the sintering behavior, microstructure, and mechanical properties of Ti₃O-Fe₂TiO₄ composites produced by the reactive spark plasma sintering (SPS) technique. The powders of Ti₃O, Ti, Fe, and TiC were utilized as the starting materials, sintered by SPS under 1500 °C at 45 MPa for 7 min. The high relative density of 97.16% was achieved for the maximum TiC content (namely 30 vol.%). X-ray diffraction patterns and microstructural observations endorsed the in situ formation of Fe₂TiO₄ compound during the SPS process. Because this phase has a low melting point, its presence could activate the liquid phase sintering mechanism, promoting the sintering behavior of the as-sintered composites. In addition, when more TiC content was added to the composite matrix, the fracture mode changed from intergranular to mixed-mode. In terms of mechanical properties, the highest macro-hardness (13.29 GPa), micro-hardness (1244.84 HV_0.3 kg), and bending strength (601 MPa) were achieved by the composite containing the highest proportion of TiC within the tested range.