Synthesis of aluminium–iron–silicon intermetallics by reaction of elemental powders

Synthesis of ternary Al–Fe–Si intermetallics starting from elemental powders using the self-propagating high temperature synthesis method is discussed in this paper. Powder mixtures corresponding to the chemical compositions of phases identified and documented in Al alloys were made, and their synthesis was carried out. Only two of the known compounds were made successfully in the pure form while others gave mixed products. Records of temperature profiles, thermal analyses and microstructure examinations indicated a transient liquid phase mechanism to be operative where liquid Al acts as a medium for the reaction. Heating the compounds to higher temperatures led to transformations to a more composition-tolerant phase. The heats of reactions computed are lower than those for binary iron aluminides. All imtermetallic compounds synthesized were very hard and possibly brittle.