Influence of Sintering Temperature on the Microstructure of TiB2 Sintered with Al3Ti Additive

Titanium diboride (TiB2) has been sintered using spark plasma sintering (SPS) with the addition of titanium tri-aluminide (Al3Ti) at the temperature between 1273 and 1573 K. By the X-ray diffraction measurements, it has been shown that TiB2–Al3Ti composites can be obtained by the sintering at 1273 K. Vickers hardness of the specimen increases as the amount of Al3Ti increases up to 30% by the sintering at 1273 K, and TiB2–30 mass% Al3Ti composite has the relative density of around 96% and Vickers hardness as high as 2100 Hv. On the other hand, Al3Ti evaporates during sintering above 1473 K. TiB2 sintered with 10 mass% Al3Ti at 1573 K has the relative density of 94% and Vickers hardness 2100 Hv, while TiB2 sintered without Al3Ti has the relative density as low as 76%. This fact indicates that Al3Ti accelerates the diffusion of TiB2 causing densification of sintered TiB2 specimens in the sintering above 1473 K.