Combustion synthesis of Fe–Al/TiC composite powders and effect of Al content on its characteristics

Abstract

In this work, combustion synthesis of ferrotitanium-Al-C powder mixtures with different compositions was carried out to synthesise Fe-Al/TiC composites. Differential thermal analysis was performed on the precursor powder from ambient temperature to 1673 K at a heating rate of 30 K min 21 . Phase development and structural changes were investigated by X-ray diffraction technique and scanning electron microscopy. The results showed that no trace of TiAl x (x51, 3) was formed in all samples, and the reaction of (Ti-Fe)-Al-C system took place in the following two steps: first, molten Al and Fe reacted exothermically to form Fe-Al intermetallic compound. Second, the produced heat melted the ferrotitanium with lower Fe content and resulted in a liquid containing Ti, Fe, Al and C. TiC formed in all samples, but depending on the Al content, different phases containing FeAl 2 , FeAl, Fe 3 Al, Fe 3 AlC x and a-Fe formed as phases of matrix. The mixture with the lower Al content gave out a higher combustion temperature.