Pressure Derivatives of Elastic Moduli in Body-Centered-Cubic (Bcc) Transition Metals and Their Solutions. Final Report, 1 June 1975-31 May 1980

摘要

Objectives are to study the elasticity, equations-of-state, and structural stability of bcc transition metals and alloys based on Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W. The studies of the elastic moduli and their pressure and temperature dependence have helped to clarify the nature of the alloy electronic band structure and its dependence on strain. The studies of elastic moduli and lattice parameters under pressure have also enabled establishing accurate P-V equations-of-state valid to several hundred kbars. We also investigated the effects of interstitial hydrogen on the elastic properties of these alloys. In the elastic studies, the elastic moduli were measured ultrasonically as functions of pressure, and in some cases temperature and hydrogen content, for single crystals of 25 different compositions. Progress was also made on the composition-pressure phase relationships in Ti-, Zr-, and Hf-based alloys. X-ray diffraction and diamond-anvil pressure cells were used to determine lattice parameters and structural phase boundaries to ultra-high pressures for the 9 elements 8 Ti-V alloys, and 4 Zr-Hf alloys. (ERA citation 08:010211)