Reaction mechanism, microstructure and properties of Ti–TiB insitu composite processed by spark plasma sintering

Conventionally, Ti–TiB composites have been processed using TiB2 or elemental boron in titanium. We report a novel method of processing Ti–TiB composite insitu through reaction between an inexpensive precursor, KBF4, and Ti using spark plasma sintering (SPS). The reaction mechanism was evaluated by differential scanning calorimetry (DSC) in combination with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The reaction happens in steps that involve different intermediate phases which finally lead to TiB. No residual TiB2 was found in the final composite unlike other methods. The insitu formed TiB whiskers refined the grain size and also homogenized the microstructure. The hardness and compressive strength increased significantly compared to cp Ti processed under same conditions.