Internal friction study of intermetallic compound Fe3Al single crystals

The temperature and magnetic field dependencies of internal friction and elastic modulus have been measured by means of the vibrating-reed technique for ferromagnetic single crystals of DO3 ordered Fe3Al around the stoichiometric composition. The residual content of carbon causes the expected variation of the Snoek peak around 500 K with heat treatments (formation of Fe-Al-carbide and possible interaction with vacancies). A slight shift of the Snoek peak with quenching and an effect of the magnetic field on the Snoek peak is noticed, indicating an additional short-range chemical C-Al interaction superposed on the long-range elastic strain interaction. The elastic modulus shows a pronounced DeltaE-effect whose temperature dependence changes with thermal treatments and during an applied magnetic field. Besides the Zener peak at about 900 K, additional relaxation peaks occur after plastic deformation and disappear after high temperature annealing. They probably correspond to Hasiguti (at 190 K) and Snoek-Koester (at 570 K) relaxations.