An example of useful application of mechanical spectroscopy to diffusion measurements was presented. A thermally activated anelastic relaxation effect was observed in Ni3Ga, an intermetallic compound of the L12 structure. The relaxation was of similar nature to that reported for Ni3Al, and was attributed to stress-induced reorientation of Ga atoms in the Ni sub-lattice. By assuming the diffusion mechanism proposed for these compounds, the diffusion coefficient of Ga was evaluated from the relaxation rate. It agrees fairly well with the extrapolation of the high-temperature data of the tracer diffusion coefficient in the literature.

Application of Mechanical Spectroscopy to Studies of Atomic Diffusion in Ordered Compounds. H.Numakura, K.Nishi: Materials Science and Engineering A, 2009, 521-522, 34-8