Shen, Andy H. and Ahrens, Thomas J. and O'Keefe, John D. (2003) Shock wave induced vaporization of porous solids. Journal of Applied Physics, 93 (9). pp. 5167-5174. ISSN 0021-8979. http://resolver.caltech.edu/CaltechAUTHORS:SHEjap03
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Strong shock waves generated by hypervelocity impact can induce vaporization in solid materials. To pursue knowledge of the chemical species in the shock-induced vapors, one needs to design experiments that will drive the system to such thermodynamic states that sufficient vapor can be generated for investigation. It is common to use porous media to reach high entropy, vaporized states in impact experiments. We extended calculations by Ahrens [J. Appl. Phys. 43, 2443 (1972)] and Ahrens and O'Keefe [The Moon 4, 214 (1972)] to higher distentions (up to five) and improved their method with a different impedance match calculation scheme and augmented their model with recent thermodynamic and Hugoniot data of metals, minerals, and polymers. Although we reconfirmed the competing effects reported in the previous studies: (1) increase of entropy production and (2) decrease of impedance match, when impacting materials with increasing distentions, our calculations did not exhibit optimal entropy-generating distention. For different materials, very different impact velocities are needed to initiate vaporization. For aluminum at distention (m)<2.2, a minimum impact velocity of 2.7 km/s is required using tungsten projectile. For ionic solids such as NaCl at distention <2.2, 2.5 km/s is needed. For carbonate and sulfate minerals, the minimum impact velocities are much lower, ranging from less than 1 to 1.5 km/s.
|Additional Information:||©2003 American Institute of Physics. Received 9 May 2002; accepted 28 January 2003. Research supported by NASA and DOE. This is contribution No. 8876, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125.|
|Subject Keywords:||porous materials; shock wave effects; impact (mechanical); entropy; thermochemistry; vaporisation; Gruneisen coefficient; equations of state; minerals|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||07 Aug 2006|
|Last Modified:||26 Dec 2012 08:58|
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