Formation of TiB2 particles during dissolution of TiAl3 in Al-TiB2 metal matrix composite using an in situ technique

A new technique has been developed in an aluminum based metal matrix composite in order to reveal the mechanism of formation of TiB2 particles by mixing molten master alloys i.e., Al-8Ti and Al-4B in the Ti:B weight ratio of 5:2. A composite containing fine TiB2 particles produced by this technique. In this approach, the progress of In situ formation of TiB2 was carried out using hot stage microscope, energy dispersive X-ray analysis, scanning electron microscopy and X-ray diffraction analysis. From the experimental observations obtained; it was proposed that the formation of TiB2 particles occurred via diffusion of Boron atoms through TiAl3 particles interface, thereby reacting to form fine TiB2 particles. Studies indicate that since the primary TiB2 particles on the surface of TiAl3 are appreciably free and movable and because of boron diffusion across boundary layer towards TiAl3, TiB2 particles produced during growth with the primary ones formed agglomeration rings. A model was schematically developed to explain the formation of TiB2. (c) 2005 Elsevier Ltd. All rights reserved.