Effective formation energies of atomic defects in D03Fe3Al: an ab-initio study

Constitutional and thermal defects in B82–SnTi2

“…The thermodynamic data are obtained from Eqs. (22) and (7). Let us point out that the expressions of E (Eq.…”

“…The formation energies and volumes of point defects in compounds can nowadays be obtained from ab initio electronic structure calculations based on density functional theory [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. The calculations are performed on large supercells containing one defect either a vacancy or an antisite.…”

“…The basic assumptions are that the energy and volume of formation of the compound depend linearly of the defect concentrations and that the entropy is calculated assuming a random distribution of the species on the lattice sites. At constant pressure and temperature, the defect concentrations are obtained either by grand potential minimization in the grand canonical ensemble [14][15][16][17][18][19][20][21][22][23][24][26][27][28][29][35][36][37][38], or by Gibbs energy minimization in the canonical ensemble [2,25,[39][40][41][42]. The two methods are equivalent.…”

“…Very few researchers treated the case where three sublattices are necessary to describe the structure of the considered phase. We may quote the works of Mayer et al [22] concerning the D0 3 -Fe 3 Al compound, Bester et al [23,24] concerning D0 3 -Ni 3 Sb compound, and Dennler and Hafner [29] concerning D0 3 -Fe 3 Si. These three works combine ab initio calculations of defect energies and a statistical model developed in the grand canonical ensemble.…”

Embedded atom method study of the interactions between point defects in iron aluminides: Double defects

“…The development of new, more ductile, Fe-Al alloys depends on a thorough understanding of their properties, implicating a better comprehension of the properties and behaviour of defects in these materials. Experimental [3][4][5] as well as theoretical studies [6][7][8][9][10][11] suggest that iron aluminides present complex point defects, especially double defects. In addition, it has been demonstrated that 'quenched-in' vacancies are responsible for a large strengthening effect both on B2 FeAl [12] and on disordered (A2) Fe-Al alloys [13,14].…”