Mechanical properties of high carbon Fe3Al-based intermetallic alloys

Fe-16 wt% Al alloys containing 0.074 to 1.1 wt% carbon were prepared by a combination of air induction melting and electroslag remelting (ESR). The cast ESR ingots exhibited a two-phase structure consisting of Fe3AlC0.5 precipitate in an Fe3Al-based matrix. The precipitate volume fraction increased with increasing carbon content of the ingot. Most of the carbon was found to be present as the Fe3AlC0.5 phase. The bulk hardness of these alloys increases linearly with increasing volume fraction of the precipitates. However, the Youngʹs modulus of these alloys was measured to be around 175 GPa and does not change significantly with change in volume fraction of the phases present. This is explained by arguing that both the matrix as well as precipitate exhibit the same modulus values for the alloys studied in the present work. Both the bulk hardness and Youngʹs modulus follow the rule of mixture for two phase alloys. However, the same may not be true for structure sensitive properties such as yield strength, ductility and creep resistance.