Identification of Metastable Phases: fcc Ti

        First-principles total-energy electronic structure calculations are used to find the epitaxial line of tetragonal Ti, i.e., the line of body-centered tetragonal (bct) structures produced by isotropic epitaxial strain on the (001) plane of tetragonal phases of Ti. An fcc phase and a higher-energy non-cubic bct phase are found at minima of the total energy with respect to tetragonal deformations, but the bcc structure is found to be a saddle point of energy. The calculation yields the strained structures, the corresponding stresses and the elastic stiffness coefficients on the epitaxial line. A segment of the epitaxial line between the two phases is shown to be inherently unstable, so that unique meaning can be given to designating a structure as strained fcc Ti. The bulk structure of a film of Ti on Al(001) is shown to be strained fcc Ti, a new phase, not on the phase diagram.

By: P. M. Marcus and F. Jona (SUNY Stony Brook)

Published in: RC20696 in 1997

This Research Report is not available electronically. Please request a copy from the contact listed below. IBM employees should contact ITIRC for a copy.

Questions about this service can be mailed to .