Diffusion of /sup 114m/In in NiAl

The mobility of Al and Ni atoms in NiAl was studied by measuring the diffusivity of /sup 114m/In in this compound. From a comparison with the diffusivities of the transition metal atoms it may be concluded that the mobilities of both species are controlled by both lattice defects V/sub Ni/ and Ni/sub Al/ in a correlated diffusion mechanism. As in the diffusion studies of the transition metal atoms a maximum in the activation energy was observed near stoichiometry for the diffusion of In. This is explained by an increasing concentration of structural defects upon deviation from stoichiometry which reduces the total activation energy by a term equal to the formation energy of thermal defects. (auth)