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⁻¹. 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 (x = 1, 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 FeAl₂, FeAl, Fe₃Al, Fe₃AlC_x and α-Fe formed as phases of matrix. The mixture with the lower Al content gave out a higher combustion temperature.

Keywords:

• X-ray diffraction
• Composites
• Intermetallics
• Self-propagating synthesis
• Phase transformation