Cálculo da energia de falha de empilhamento através da teoria do funcional da densidade

Abstract

Due to the large number of possible compositions, multicomponent alloys present a wide spectrum of properties, especially mechanical, when compared to traditional ones. In this context, the use of methods that allow knowing in advance the effect of composition on the properties of these alloys is essential to enable their development with optimized experimental effort. In particular, various alloys that undergo the TRIP (transformation-induced plasticity) and TWIP (twinning-induced plasticity) effects during plastic deformation tend to exhibit excellent combinations of strength and ductility. The activation of these deformation mechanisms is directly associated with the stacking fault energy, a property whose experimental determination, although possible, is not feasible for large amounts of compositions. Computational simulation methods based on quantum mechanics, that is, first principles methods, such as those based on density functional theory, allow estimating this property for the most varied compositions and, therefore, the optimized development of new alloys. Thus, in this work, the two main methods for calculating the stacking fault energy through density functional theory – the supercell method and the axial interaction model – are presented and their advantages and disadvantages are analyzed. Furthermore, an introduction to density functional theory and related concepts is briefly presented.