THE SOLUBILITY OF HYDROGEN IN NIAL

Measurements of the H-solubility of stoichiometric NiAl in the tempera ture range 670-1373 K have been carried out at a constant H-2 gas pres sure of 1.01 x 10(5) Pa. The data obtained are not consistent with sim ple mixing statistics where the H-atoms occupy unique interstitial sit es in the B2 cubic NiAl lattice. The thermodynamic behavior is consist ent with a model in which H-atoms may occupy both tetrahedral and octa hedral sites and the relative site occupancy depends on the temperatur e. (C) 1998 Acta Metallurgica Inc.