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Title: Dynamic reflectance changes in high-purity zirconium when it is shocked from the α to ω phase

Abstract

Flash lamp-illuminated integrating spheres have been used to measure the dynamic reflectance at the interface between a shocked metal target and a window maintaining the shock stress. In conjunction with radiance measurements, this method was recently used to study the pressure versus temperature phase boundary of the beta phase to body-centered-tetragonal transition of tin at around 13 GPa and, in separate experiments, to show a relationship between the reflectance and the phase fraction. We have used this technique to measure the ratio, R, of the dynamic reflectance relative to the ambient value for a high-purity zirconium sample attached to a sapphire window to study the alpha to omega phase transition. Nine experiments cover the range of stress, σ, from 4 to 16 GPa at six wavelengths from 500 to 1550 nm. The two phases in zirconium differ in volume by <1%, so a phase change between them can be difficult to identify from anomalies in the particle velocity measured on the shock Hugoniot. The phase boundary is believed to cross the Hugoniot around 3 GPa, but dynamically it is observed at much higher stresses >6 GPa. Our results show that the relative reflectance decreases upon initial shock in the alphamore » state but increases as the material transforms to its omega state. The slope dR/dσ changes the sign around the phase transition. For shocks below 6 GPa, dR/dσ < 0, and for σ above 10 GPa, dR/dσ > 0. In the stress region between 6 and 10 GPa, dR/dσ varies somewhat, perhaps due to the band structure or because the transition is incomplete there. I. INTRODUCTION« less

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [1];  [1];  [4]
  1. Nevada National Security Site, Santa Barbara, CA (United States). Special Technologies Lab.
  2. Nevada National Security Site, Los Alamos, NM (United States). New Mexico Operations
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Nevada National Security Site, Santa Barbara, CA (United States). Special Technologies Lab.; Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1492673
Report Number(s):
LA-UR-18-28548
Journal ID: ISSN 0021-8979
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 124; Journal Issue: 18; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS

Citation Formats

Stevens, G. D., Scharff, R. J., Lang, J. M., La Lone, B. M., Turley, W. D., and Veeser, L. R. Dynamic reflectance changes in high-purity zirconium when it is shocked from the α to ω phase. United States: N. p., 2018. Web. doi:10.1063/1.5054893.
Stevens, G. D., Scharff, R. J., Lang, J. M., La Lone, B. M., Turley, W. D., & Veeser, L. R. Dynamic reflectance changes in high-purity zirconium when it is shocked from the α to ω phase. United States. doi:10.1063/1.5054893.
Stevens, G. D., Scharff, R. J., Lang, J. M., La Lone, B. M., Turley, W. D., and Veeser, L. R. Wed . "Dynamic reflectance changes in high-purity zirconium when it is shocked from the α to ω phase". United States. doi:10.1063/1.5054893. https://www.osti.gov/servlets/purl/1492673.
@article{osti_1492673,
title = {Dynamic reflectance changes in high-purity zirconium when it is shocked from the α to ω phase},
author = {Stevens, G. D. and Scharff, R. J. and Lang, J. M. and La Lone, B. M. and Turley, W. D. and Veeser, L. R.},
abstractNote = {Flash lamp-illuminated integrating spheres have been used to measure the dynamic reflectance at the interface between a shocked metal target and a window maintaining the shock stress. In conjunction with radiance measurements, this method was recently used to study the pressure versus temperature phase boundary of the beta phase to body-centered-tetragonal transition of tin at around 13 GPa and, in separate experiments, to show a relationship between the reflectance and the phase fraction. We have used this technique to measure the ratio, R, of the dynamic reflectance relative to the ambient value for a high-purity zirconium sample attached to a sapphire window to study the alpha to omega phase transition. Nine experiments cover the range of stress, σ, from 4 to 16 GPa at six wavelengths from 500 to 1550 nm. The two phases in zirconium differ in volume by <1%, so a phase change between them can be difficult to identify from anomalies in the particle velocity measured on the shock Hugoniot. The phase boundary is believed to cross the Hugoniot around 3 GPa, but dynamically it is observed at much higher stresses >6 GPa. Our results show that the relative reflectance decreases upon initial shock in the alpha state but increases as the material transforms to its omega state. The slope dR/dσ changes the sign around the phase transition. For shocks below 6 GPa, dR/dσ < 0, and for σ above 10 GPa, dR/dσ > 0. In the stress region between 6 and 10 GPa, dR/dσ varies somewhat, perhaps due to the band structure or because the transition is incomplete there. I. INTRODUCTION},
doi = {10.1063/1.5054893},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 18,
volume = 124,
place = {United States},
year = {2018},
month = {11}
}

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