A study on the combustion synthesis of titanium aluminide in the self-propagating mode

Abstract

The combustion synthesis of titanium aluminide (TiAl) starting from elemental powders in the self-propagating mode was investigated. A novel technique involving inductive preheating and ignition was utilized to initiate the reaction in a powder mixture compact. The effects of compact green density, titanium particle size, and mechanical activation of powder mixture on the propagation rate and combustion temperature were evaluated. It was found that mechanical activation of green powder mixture up to 2 h, and using finer titanium particles resulted in higher reaction front propagation rates. The optimum value of relative density with respect to front propagation velocity was determined to be within the range of 65–70%. The maximum combustion temperature was similarly obtained in the above range of relative density, but it was not significantly affected by the titanium particle size. The time-to-ignition was found to be highly influenced by titanium particle size and milling time. The products were characterized by X-ray diffraction and it was found out that the products were solely consisted of the TiAl phase without any other detectable phases.