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. [doi:10.2320/matertrans.M2012113]