EXAFS Measurements of Laser-Shocked V and Ti and Crystal Phase Transformation in Ti [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2004.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
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- PDF-file: 17 pages; size: 0.3 Mbytes
- Additional Creators:
- Lawrence Berkeley National Laboratory
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information
- Extended X-Ray Absorption Fine Structure (EXAFS), using a laser-imploded target as a source, can yield the properties of laser-shocked metals on a nanosecond time scale. EXAFS measurements of vanadium shocked to ≈0.4 Mbar yield the compression and temperature in good agreement with hydrodynamic simulations and shock-speed measurements. In laser-shocked titanium at the same pressure, the EXAFS modulation damping is much higher than warranted by the predicted temperature increase. This is shown to be due to the α-Ti to ω-Ti crystal-phase transformation, known to occur below ≈0.1 Mbar for slower shock waves. The dynamics of material response to shock loading has been extensively studied in the past . The goal of those studies has been to understand the shock-induced deformation and structural changes at the microscopic level . Laser-generated shocks can be employed to broaden these studies to higher pressures (≈1 Mbar) and strain rates (≈ 10⁷-10⁸ s⁻¹). Recently, laser-shocked materials have been studied with in-situ x-ray diffraction [3,4]. The goal of this work is to examine the use of in-situ EXAFS  as a complementary characterization of laser-shocked metals. EXAFS is the modulation in the x-ray absorption above the K edge (or L edge) due to the interference of the photoelectron waves with the waves reflected from neighboring atoms. The frequency of EXAFS modulations is related to the inter-particle distance, hence to the compression. The damping rate of the modulation can yield the lattice temperature, which is not readily available by other methods.
- Published through SciTech Connect.
Physical Review Letters, vol. 92, no. 9, March 5, 2004, pp. 095504 92 9 ISSN 0031-9007; PRLTAO FT
Allen, P G; Meyerhofer, D D; Boehly, T R; Remington, B A; Pollaine, S M; Albers, R C; Rehr, J J; Yaakobi, B.
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