Compression studies of TiB{sub 2} using synchrotron x-ray diffraction and ultrasonic techniques
- Hawaii Institute of Geophysics and Planetology, School of Ocean Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822 (United States)
The compressibility of TiB{sub 2} has been determined separately by synchrotron x-ray diffraction and ultrasonic measurements on samples loaded in diamond-anvil cells and in multianvil high-pressure apparatus up to pressures of 65.9 GPa and 13.9 GPa, respectively, at ambient temperature. The high-pressure x-ray diffraction measurements, carried out on a pure polycrystalline sample, show a monotonic decrease of the lattice parameters with pressure, with the c/a ratio variation suggesting an increase in the structural rigidity along the c direction. No structural transition is observed even after laser heating of the sample up to 2200 K at 40 GPa, indicating a phase stability of TiB{sub 2} in this pressure range. The ultrasonic measurements of compressional V{sub p} and shear V{sub s} velocities on a cylindrical specimen show linear pressure dependencies. Using the third-order Eulerian finite strain equation to fit the pressure-volume x-ray data, we obtain an isothermal bulk modulus of K{sub To}=232.9{+-}4.2 GPa and its pressure derivative K{sub To}{sup '}=3.86{+-}0.23. Similarly, the parameters derived from fitting the finite strain equation to the ultrasonic data give an adiabatic bulk modulus of K{sub So}=232.9{+-}1.6 GPa and K{sub So}{sup '}=3.02{+-}0.24, in good agreement with the x-ray diffraction measurements. The shear modulus and its pressure derivative derived from the ultrasonic measurements are G{sub So}=259.8{+-}0.4 and G{sub So}{sup '}=2.52{+-}0.01, respectively.
- OSTI ID:
- 20664993
- Journal Information:
- Journal of Applied Physics, Vol. 97, Issue 2; Other Information: DOI: 10.1063/1.1836857; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMBIENT TEMPERATURE
COMPRESSIBILITY
COMPRESSION
CYLINDRICAL CONFIGURATION
DIAMONDS
EQUATIONS OF STATE
LASER-RADIATION HEATING
LATTICE PARAMETERS
PHASE STABILITY
POLYCRYSTALS
PRESSURE RANGE GIGA PA
STRAINS
STRESSES
SYNCHROTRONS
TEMPERATURE RANGE 1000-4000 K
TITANIUM BORIDES
ULTRASONIC TESTING
X-RAY DIFFRACTION