J. Phys. IV France
Volume 05, Numéro C1, Janvier 1995
Europhysics Industrial Workshop EIW-12
Industrial Applications of Positron Annihilation
Page(s) C1-157 - C1-161
Europhysics Industrial Workshop EIW-12
Industrial Applications of Positron Annihilation

J. Phys. IV France 05 (1995) C1-157-C1-161

DOI: 10.1051/jp4:1995118

Investigation of Defects and Atomic Ordering in Fe72Al28 by Positron Annihilation and Mössbauer Spectroscopy

Y. Jiraskova1, O. Schneeweiss1, M. Sob1, I. Novotny2, I. Prochazka2, F. Becvar2, B. Sedlak2, F. Sebesta3 and M.J. Puska4

1  Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, CZ-616 62 Brno, Czech Republic
2  Department of Low-Temperature Physics, Charles University, V Holesovickach 2, CZ-180 00 Praha 8, Czech Republic
3  Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Brehova 7, CZ-115 19 Praha, Czech Republic
4  Laboratory of Physics, Helsinki University of Technology, SF-02150 Espoo, Finland

Iron aluminide Fe72Al28 was investigated in states with different defect concentrations using the positron annihilation lifetime and Mössbauer spectroscopy methods. The dominant component of 178-187 ps, obtained from positron lifetime spectra analysis, corresponds to a high density of vacancies. In the sample where high concentrations of vacancies or dislocations and vacancy clusters were found simultaneously, a second component with a lifetime of 335 ps appears. Mössbauer results show that in the alloy above the Fe3Al stoichiometry concentration the vacancies prefer to occupy the sublattice in the DO3 superstructure which is reserved for both iron and aluminium atoms. However, this conclusion could not be verified by comparison of theoretical and experimental values of positron lifetimes as the theoretically predicted positron lifetimes for all three types of vacancies are nearly the same.

© EDP Sciences 1995