Effects of Nb and C additions on the microstructure and tensile properties of lightweight ferritic Fe-8Al-5Mn alloy

Additions of Nb and C result in the formation of NbC and kappa-carbide in Fe-8Al-5Mn alloy. Both NbC and kappa-carbide particles inhibit recrystallization during hot rolling with the resultant formation of pancake-shaped grain structure in Fe-8Al-5Mn-0.1Nb-0.1C alloy, but kappa-carbide particles also promote recrystallization via particle-stimulated nucleation mechanism during subsequent warm/cold rolling and annealing. As a result, Fe-8Al-5Mn-0.1Nb-0.1C alloy has a much finer grain size and a better combination of tensile properties than Fe-8Al-5Mn alloy. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.