Positron annihilation study of vacancies in Fe-Al based alloys

In the present contribution, high-resolution positron lifetime and coincidence Doppler broadening spectroscopies are used to characterize defects in Fe76Al24 and Fe72Al28 alloys. In order to facilitate defect identification, we also perform a theoretical study of basic vacancy-like defects in three phases of the Fe-Al system: ordered, short-range ordered, and disordered. Positron characteristics, like positron lifetime, positron binding energy to defects, high-momentum parts of Doppler broadening curves and specific trapping rates, are calculated for various defect configurations. The results are discussed in the context of experimental data obtained here and available in literature.