Phase stability and elastic properties of C15 compounds HfV{sub 2}+Nb
- Los Alamos National Lab., NM (United States)
- Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Materials Science and Engineering
The ternary phase diagram of Hf-V-Nb system has been established and the C15 and C14 Laves phase regions located. The structural stability of the cubic Laves phase HfV{sub 2}+Nb was examined using heat capacity measurements and transmission electron microscopy. It is found that the binary C 15 has a martensitic transformation at 115K and that Nb addition can eliminate the martensitic transformation and stabilize the C15 structure. The elastic properties vs. temperature of the C15 HfV{sub 2}+Nb were studied using the resonant ultrasound technique. It is observed that the shear and Young`s moduli increase abnormally with increasing temperature, the bulk modulus is virtually constant, and the Poisson`s ratio is very high and decreases abnormally with increasing temperature. The elastic properties of the C15 compound can be qualitatively understood using the electronic structure obtained from ab initio calculations. The relation between the phase stability and anomalous elastic properties is discussed based on these results.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States); National Aeronautics and Space Administration, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10187361
- Report Number(s):
- LA-UR--94-3247; CONF-9410184--2; ON: DE95000940; CNN: Grant N00014-91-J-1165P02; Grant DMR91-20668
- Country of Publication:
- United States
- Language:
- English
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