Atomic jumps and diffusion in Ni3Al studied by anelastic relaxation measurements

Detailed experiments of isothermal mechanical spectroscopy have been made on the anelastic relaxation effect in Ni3Al, which was interpreted to be due to stress-induced reorientation of antisite Al atoms in the majority sublattice normally occupied by Ni atoms. The relaxation strength has been found to increase sensitively with increasing Al concentration, supporting firmly the earlier interpretation. The observed relaxation rates have been analysed on the basis of the mechanism of atomic diffusion proposed by Numakura and co-workers, and the diffusion coefficient of Al in Ni3Al has been evaluated.