Structural properties of metastable phases in Zr-Nb alloys: III.The athermal omega phase

AURELIO, G.; A. FERNÁNDEZ GUILLERMET; CUELLO, G. J.; CAMPO, J.

JOURNAL OF ALLOYS AND COMPOUNDS

Elsevier

Año: 2002 vol. 335 p. 132 - 138

0925-8388

By means of high-resolution neutron diffraction experiments, a new study of the lattice parameters and other structural properties as ell as the mass fraction of the V phase formed by quenching Zr–Nb alloys, has been made.With the present results and those from the rcent neutron diffraction work by Benites and co-workers (J. Alloys Comp. 299 (2000) 183; 302 (2000) 192) reported on papers I and II f this series, an analysis is performed of the composition dependence of various key aspects of the diffusionless (‘athermal’) V phasetransition in the Zr–Nb system. In particular, we discuss the misfit between the V particles and the parent bcc phase, the hexagonal to trigonal symmetry change occurring in V and the effect of the latter upon the shortest interatomic distance in this phase. The picture emerging from the present study is also used to investigate the interatomic distance correlation previously reported by Grad et al. (Z. Metallkd. 87 (1996) 726).