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

Synthesis of ternary Al-Fe-Si intermetallics starting from elemental powder s 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 synth esis was carried out. Only two of the known compounds were made successfull y in the pure form while others gave mixed products. Records of temperature profiles, thermal analyses and microstructure examinations indicated a tra nsient liquid phase mechanism to be operative where liquid Al acts as a med ium for the reaction. Heating the compounds to higher temperatures led to t ransformations to a more composition-tolerant phase. The heats of reactions computed are lower than those for binary iron aluminides. All imtermetalli c compounds synthesized were very hard and possibly brittle. (C) 2000 Elsev ier Science S.A. All rights reserved.