Effect of thermo-mechanical processing and heat treatment on structure and mechanical properties of an electroslag remelted Fe-8.5wt%Al-1.1wt%C alloy

Electroslag remelted (ESR) ingots of Fe-8.5wt%Al-1.1wt%C alloy were hot forged at 1373 K to 83% reduction. The forged ingots were hot rolled at 1373 K to 53% rolling reduction and heat treated at 1173 K for one h. The thermo-mechanical processing and heat treatment of the ESR alloy ingots resulted in breakdown of cast dendritic structure leading to a homogeneous microstructure with fine Fe3AlC0.5 precipitates. This was accompanied by a significant improvement in ductility and strength of the alloy. It is shown that the addition of carbon to Fe-8.5wt%Al binary alloy does not result in a significant loss in ductility. The presence of Fe3AlC0.5 precipitates results in an increase in strength and improvement in creep and stress rupture properties. The cast and wrought alloys exhibited similar creep and stress rupture properties. The reasons for this are discussed. An attractive combination of strength, ductility and creep and stress rupture properties not yet reported for Fe-Al alloys was achieved by thermomechanical processing and heat treatment. (C) 1999 Elsevier Science S.A. All rights reserved.