The stability of C15 HfV{sub 2}+Nb: Experiments and ab initio calculations
- Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering
The phase diagram for the Hf-V-Nb system at 1,000 C was established and the phase fields of a C15 and a C14 Laves phases were located. The stability of the C15 compound HfV{sub 2}+Nb was studied. High temperature x-ray diffraction showed that the C15 phase is stable from room temperature to 700 C, but low temperature specific heat measurements showed that it is unstable if the Nb content is too low. LMTO calculations were made for the binary compound. The band structure, the total and partial densities of states, and the Fermi surface were determined. It was found that the instability of the C15 phase is due to a soft phonon mode driven by strong electron-phonon coupling combined with Fermi surface nesting. These results are used to explain the origins of the phase stability in the ternary alloy.
- OSTI ID:
- 72418
- Report Number(s):
- CONF-9310224--; ISBN 0-87339-249-3
- Country of Publication:
- United States
- Language:
- English
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