Structure of Defects, their Interactions and Positron Characteristics in Fe3 Alsystem

Various defect properties in Fe3Al are studied theoretically. In particular, defect formation energies for vacancies and antisites are determined on the basis of ab initio calculations. Defect concentrations and defect interactions are examined as well. Positron lifetimes for the most probable trapping sites in Fe3Al are obtained and compared with available experimental data. Finally, specific features of coincidence Doppler broadening spectra for selected defects in Fe3Al are discussed in terms of the desired defect identification.