Indexed on: 01 Jun '98Published on: 01 Jun '98Published in: Metallurgical and Materials Transactions B
By making use of a novel technique in which TiB2 particulates are fabricated by an in situ reaction in molten aluminum, we have successfully produced TiB2/Al composites. In order to reveal the characteristic of the technique, the mechanism of formation of TiB2 particulates obtained by this method is studied in this article. Both theoretical and experimental results have shown that the TiB2 particulates are formed by a diffusion mechanism when the molar fraction of aluminum in the preform is higher than 43.5 pct. In this case, the TiB2 particulates are generally spherical, and their mean size is less than 2.0 µm. On the contrary, the TiB2 particulates are formed by a solution-precipitation mechanism when the fraction is lower than 43.5 pct. In this case, the TiB2 particulates are multifaceted, and the size of most particulates lies between 3.0 and 6.0 µgm.