Surface Specularity as an Indicator of Shock-Induced Solid-Liquid Phase Transitions
When highly polished metal surfaces melt upon release after shock loading, they exhibit a number of features that suggest that significant surface changes accompany the phase transition. The reflection of light from such surfaces changes from specular (pre-shock) to diffuse upon melting. A familiar manifestation of this phenomenon is the loss of signal light in velocimetric measurements typically observed above pressures high enough to melt the free-surface. Unlike many other potential material phase-sensitive diagnostics (e.g., reflectometery, conductivity), changes in the specularity of reflection provide a dramatic, sensitive indicator of the solid-liquid phase transition. Data will be presented from multiple diagnostics that support the hypothesis that specularity changes indicate melt. These diagnostics include shadowgraphy, infrared imagery, high-magnification surface images, interferometric velocimetry, and most recently scattering angle measurements.
- Research Organization:
- National Security Technologies, LLC (NSTec), Mercury, NV (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NA)
- DOE Contract Number:
- DE-AC52-06NA25946
- OSTI ID:
- 946607
- Report Number(s):
- DOE/NV/25946-126; TRN: US200903%%557
- Journal Information:
- American Physical Society, 15th APS Topical Conference on Shock Compression of Condensed Matter, June 24-29,2007, Conference: 2007 Shock Compression of Condensed Matter American Physical Society Conference, Hawaii, June 23-29, 2007
- Country of Publication:
- United States
- Language:
- English
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