Tan, Hua and Ahrens, Thomas J. (1990) Shock induced polymorphic transition in quartz, carbon, and boron nitride. Journal of Applied Physics, 67 (1). pp. 217-224. ISSN 0021-8979. http://resolver.caltech.edu/CaltechAUTHORS:TANjap90
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A theory describing the polymorphism induced by shock waves in silicates, oxides, sulfides, and many inorganic solids is presented. Shock wave experiments conducted on these and other materials indicate that many transformations to high-pressure phases are triggered via the production of shear bands and, in some cases, formation of high-density amorphous phases. Shock states in the mixed phase regimes, of quartz, carbon, and boron nitride, are quantitatively described in terms of the properties of both their low- and high-pressure phases. Good agreement between the calculated results and measured Hugoniot data in the mixed phase regime is obtained. By fitting the pressures of the onset of the phase transition from graphite to diamond, and associating its triggering with crossing the extension of the metastable melting line of graphite, we obtain a similar shaped curve to the metastable melting line obtained by Bundy [J. Geophys. Res. 85, 6930 (1980)]. Similarly, the transition from quartz to stishovite is associated with the metastable melting line of coesite. The present theory, when fit to the onset of the mixed phase regime of graphitelike boron nitride transforming to cubic boron nitride Hugoniot, predicts the standard entropy for cubic BN to be 0.4–0.5 J/g K.
|Additional Information:||Copyright © 1990 American Institute of Physics. Received 8 May 1989; accepted 31 July 1989. Research supported under NASA Contract No. NGL-05-002-105; Defense Nuclear Agency, Contract No. DNA-001-87-C-0125; and Army Research Office Contract No. DAA-LO3-88K0199. Contribution No. 4950, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California.|
|Subject Keywords:||QUARTZ, CARBON, BORON NITRIDES, SHOCK WAVES, PHASE TRANSFORMATIONS, POLYMORPHISM, AMORPHOUS STATE, HUGONIOTS, METASTABLE PHASES, ENTROPY, VERY HIGH PRESSURE|
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|Deposited On:||15 Apr 2008|
|Last Modified:||26 Dec 2012 09:57|
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