A Study of Point Defects in the B2-Phase Region of the Fe-Al System by Mossbauer Spectroscopy

Abstract

In this work, we employed the Mössbauer spectroscopy and X-ray powder diffraction in a study of point defect 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 defect determined from positron annihilation data. In the MÄossbauer effect, two types of samples are investigated: Fe{Al alloys with few additives obtained by induction melting and Al-rich metallic powders produced by the self-decomposition method and intensive grinding of high energy in the electro-magneto-mechanical mill. We present the values of the 57Fe isomer shift and quadrupole splitting for the components describing the point defect in the local environment of a MÄossbauer nuclide. The concentration of the Fe vacancies and Fe atoms substituting Al (Fe{AS) are determined. The results showed that an increase in Al content causes an increase in vacancy and Fe{AS concentration.