The properties of Cr in α-Fe were investigated by ab initio calculations based upon density functional theory. The intrinsic point defect formation energies were found to be larger in model bcc Cr as compared to those in ferromagnetic bcc Fe. The interactions of Cr with point defects (vacancy and self-interstitials) were characterized. Single Cr atoms interacted weakly with vacancies but significantly with self-interstitial atoms. Mixed interstitials of any interstitial symmetry were bound. Configurations where two Cr atoms were in nearest-neighbor position were generally unfavorable in body-centered cubic Fe except when they were a part of a ⟨111⟩ interstitial complex. Mixed ⟨110⟩ interstitials did not have as strong directional stability as pure Fe interstitials have. The effects on the results using the atom description scheme of either the ultra-soft pseudopotential or the projector augmented wave formalisms were connected to the differences in local magnetic moments that the two methods predict. As expected for the Fe-Cr system, the results obtained using the projector augmented wave method were more reliable than the ones obtained with the ultra-soft pseudopotential.

Ab initio Study of Cr Interactions with Point Defects in BCC Fe. P.Olsson, C.Domain, J.Wallenius: Physical Review B, 2007, 75[1], 014110 (12pp)