Elastic properties of C40 transition metal disilicides
- Los Alamos National Lab., NM (United States). Center for Materials Science
- Quatrosonics, Inc., Albuquerque, NM (United States)
Room-temperature and low temperature elastic properties of hexagonal C40 transition metal disilicides, NbSi{sub 2} and TaSi{sub 2}, have been studied using Resonant Ultrasound Spectroscopy (RUS). All five independent elastic stiffness constants c{sub ij} for NbSi{sub 2} and TaSi{sub 2} single crystals have been obtained. The temperature dependence of the c{sub ij} is normal but not large. The orientation dependence of the Young`s and shear moduli was examined in comparison with other transition metal disilicides. The room temperature shear moduli in the {l_brace}0001{r_brace} plane, with values of 145.3 and 143.7 GPa for NbSi{sub 2} and TaSi{sub 2} respectively, are low relative to those in the equivalent pseudo hexagonal {l_brace}220{r_brace} close-packed plane for tetragonal C11{sub b} MoSi{sub 2} and WSi{sub 2}. The isotropic elastic constants for polycrystalline materials were also calculated. The results show that the various moduli are all much higher than those of the constituent elements. The room temperature Poisson`s ratios of NbSi{sub 2} and TaSi{sub 2} are 0.18 and 0.19, respectively, which are smaller than those of the constituent elements and smaller than most materials. The Debye temperatures, {theta}{sub D}, were estimated to be 688 K for NbSi{sub 2} and 552 K for TaSi{sub 2}. The elastic properties of C40 VSi{sub 2}, NbSi{sub 2}, TaSi{sub 2}, and CrSi{sub 2} and C11{sub b} MoSi{sub 2} and WSi{sub 2} are compared and the possible influence on mechanical behavior discussed.
- OSTI ID:
- 367314
- Journal Information:
- Acta Materialia, Vol. 44, Issue 8; Other Information: PBD: Aug 1996
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NIOBIUM SILICIDES
ELASTICITY
TANTALUM SILICIDES
VANADIUM SILICIDES
CHROMIUM SILICIDES
MOLYBDENUM SILICIDES
TUNGSTEN SILICIDES
INTERMETALLIC COMPOUNDS
MONOCRYSTALS
TEMPERATURE DEPENDENCE
ORIENTATION
YOUNG MODULUS
SHEAR PROPERTIES
TETRAGONAL LATTICES
HEXAGONAL LATTICES
POLYCRYSTALS
POISSON RATIO
DEBYE TEMPERATURE
MECHANICAL PROPERTIES