The logarithmic decrement was measured, in Nb-Mo(V)-O alloys with Mo or V contents of up to 50at%, by using a low-frequency (3 to 7Hz) inverse torsion pendulum at temperatures ranging from 20 to 700C. The complex decrement versus temperature curves were analyzed in terms of their constituent peaks, and the parameters of these peaks were used to derive information on the distribution of O atoms in octahedral interstitial sites which differed with regard to the number of Mo or V atoms which were present in surrounding nearest-neighbor lattice sites. This information was used to determine the Mo(V)-O binding energy and the structure potential barrier for O atom diffusion in alloys with strong (V-O) and weak (Mo-O) interactions. A small (0 to 1.4kJ/mol) absolute value of the Mo-O binding energy, and a positive sign, corresponded to a weak repulsion between Mo-O atoms at 150 to 400C. This changed slightly for complexes with Mo(V) nearest neighbors of 1 to 3. There was a strong interaction of a chemical nature, between V-O atoms in Nb-V-O alloys with up to 5at%V, which was produced by a V-O binding energy of -46kJ/mol and a 2V-O binding energy of -61kJ/mol.

N.P.Kushnareva, S.E.Snejko: Journal of Alloys and Compounds, 1994, 211-212, 75-9