Characterisation of titanium–titanium boride composites processed by powder metallurgy techniques

In this work, a detailed characterisation of titanium–titanium boride composites processed by three powder metallurgy techniques, namely, hot isostatic pressing, spark plasma sintering and vacuum sintering, was conducted. Two composites with different volume percents of titanium boride reinforcement were used for the investigation. One was titanium with 20% titanium boride, and the other was titanium with 40% titanium boride (by volume). Characterisation was performed using X-ray diffraction, electron probe micro analysis — energy dispersive spectroscopy and wavelength dispersive spectroscopy, image analysis and scanning electron microscopy. The characterisation results confirm the completion of the titanium boride reaction. The results reveal the presence of titanium boride reinforcement in different morphologies such as needle-shaped whiskers, short agglomerated whiskers and fine plates. The paper also discusses how mechanical properties such as microhardness, elastic modulus and Poisson's ratio are influenced by the processing techniques as well as the volume fraction of the titanium boride reinforcement.

► Ti–TiB composites were processed by HIP, SPS and vacuum sintering.
► The completion of Ti–TiB2 reaction was confirmed by XRD, SEM and EPMA studies.
► Hardness and elastic properties of Ti–TiB composites were discussed.
► Processing techniques were compared with respect to their microstructure.