Synthesis, microstructure and mechanical properties of Ti3SiC2–TiC composites pulse discharge sintered from Ti/Si/TiC powder mixture

Abstract

Ti3SiC2–TiC composites with the volume fractions of TiC from 0 to 90% were fabricated by pulse discharge sintering (PDS) technique using Ti–Si–TiC as starting powders in the sintering temperature range of 1250–1400°C. Phase content and microstructure of the synthesized samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The samples sintered at 1400°C are almost fully dense for all compositions with relative density higher than 98%. The phase distribution in the synthesized samples is non-uniform. The Vickers hardness increases almost linearly with the volume fraction of TiC up to a value of 20.1±1.4GPa at 90vol.% TiC. The flexural strength increases with the volume fraction of TiC to a maximum value of 655±10MPa at 50vol.% TiC. The relationship between microstructure and mechanical properties is discussed.