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

Atomic Jumps and Diffusion in Ni3Al Studied by Anelastic Relaxation Measurements. Numakura, H., Nishi, K.: Materials Science and Engineering A, 2006, 442[1-2], 59-62

Figure 6

Diffusion of Fe and Ni in a Ni75.5Al24.5/Ni70.0Al24.0Fe6.0 couple

White circles, i = Fe; black circles, i = Ni