A study of combustion synthesis reaction in the Ti+C/Ti+Al system

Combustion synthesis (SHS) of the Ti+C/Ti+Al system was investigated by using titanium, graphite and aluminum powders as reactants. These powders were thoroughly mixed and pressed into cylindrical compacts, and heated in an argon atmosphere. The effects of the reactant composition and the heating rate were studied. The phase identification and morphology observation of the products were carried out by X-ray diffraction (XRD) and scanning electronic microscopy (SEM), respectively. XRD analysis showed that the products, in addition to the expected TiC/TiAl phases, also contained an appreciable amount of the ternary carbide (i.e., TixAlC). The heating rate was found to strongly affect the extent of the combustion reaction. A possible reaction mechanism based on the experimental results was proposed to describe the whole process of the SHS reaction and the characteristic product morphology. It was considered that the ternary carbides may be formed by the peritectic reaction between TiC and the Ti-Al melt during the cooling stage after combustion. (C) 2004 Kluwer Academic Publishers.