Point defects in the B2 - phase region of the Fe-Al system studied by Mössbauer spectroscopy and X-ray diffraction

In this work Mössbauer spectroscopy and X-ray powder diffraction was used to study of point defects formation in intermetallic phases of the B2 structure of the Fe-Al system as a function of Al concentration. The results are compared with the concentrations of point defects determined from positron annihilation data. The values of the 57Fe isomer shift and quadrupole splitting for the components describing the point defects in the local environment of a Mössbauer nuclide are presented. The concentration of the Fe vacancies and Fe atoms substituting Al (i.e. anti-site atom, Fe-AS) are determined. The results show that an increase in Al content causes an increase in vacancy and Fe-AS concentrations.