Atomic-scale modeling of Fe-Al-Mn-C alloy using pair models and Monte-Carlo calculations
Résumé
The Fe-Al-Mn-C system is widely studied for automotive applications due to its good mechanical properties and relatively low density. Our work is devoted to the atomic-scale modeling of this system and to start with, we focused on the well-documented Fe-Al binary system. More precisely, we tested the capability to reproduce its phase diagram combining ab initio calculations and cluster expansion methods. Several models were built using different input atomic configurations: pure iron, a substitutional aluminium atom diluted in iron, pairs of substitutional aluminium atoms located at different neighbour shells and complementary structures (B2, B32 and D0(3)). Long-range order parameters (occupation of sublattices) were defined to analyse the equilibrium configurations generated by Monte-Carlo runs in the semi-grand canonical ensemble. Phase diagrams were plotted for each model and compare well with experimental ones.