In situ processing of TiB2/TiC ceramic composites by thermal explosion under pressure: experimental study and modeling

A model describing non-isothermal reactive diffusion in B4C–Ti powder blends leading to thermal explosion (TE/SHS) in the conditions of enhanced heat transfer into the surrounding ambience was developed. The model explicitly incorporates the reaction kinetics and is based on previously reported experimental kinetics of isothermal growth of diffusion layers at a flat B4C/Ti interface. In spite of a number of simplifications (spherical geometry, sequential reactions of TiB and TiB2 formation, etc.), a good agreement between the model calculations and experimental results on TE/SHS in B4C–3Ti dense samples placed between the preheated rams of a press has been obtained. The B4C powder particle size was found to significantly affect the ignition of TE, and the combustion process could be controlled by addition of small amounts of very fine powder fraction.