In situ observation of a phase transition in silicon carbide under shock compression using pulsed x-ray diffraction in SITU OBSERVATION of A PHASE ... S. J. TRACY et al.

S. J. Tracy, R. F. Smith, J. K. Wicks, D. E. Fratanduono, A. E. Gleason, C. A. Bolme, V. B. Prakapenka, S. Speziale, K. Appel, A. Fernandez-Pañella, H. J. Lee, A. MacKinnon, F. Tavella, J. H. Eggert, T. S. Duffy

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Abstract

The behavior of silicon carbide (SiC) under shock compression is of interest due to its applications as a high-strength ceramic and for general understanding of shock-induced polymorphism. Here we use the Matter in Extreme Conditions beamline of the Linac Coherent Light Source to carry out a series of time-resolved pump-probe x-ray diffraction measurements on SiC laser-shocked to as high as 206 GPa. Experiments on single crystals and polycrystals of different polytypes show a transformation from a low-pressure tetrahedral phase to the high-pressure rocksalt-type (B1) structure. We directly observe coexistence of the low- and high-pressure phases in a mixed-phase region and complete transformation to the B1 phase above 200 GPa. The densities measured by x-ray diffraction are in agreement with both continuum gas-gun studies and a theoretical B1 Hugoniot derived from static-compression data. Time-resolved measurements during shock loading and release reveal a large hysteresis upon unloading, with the B1 phase retained to as low as 5 GPa. The sample eventually reverts to a mixture of polytypes of the low-pressure phase at late times. Our study demonstrates that x-ray diffraction is an effective means to characterize the time-dependent structural response of materials undergoing shock-induced phase transformations at megabar pressures.

Original languageEnglish (US)
Article number214106
JournalPhysical Review B
Volume99
Issue number21
DOIs
StatePublished - Jun 17 2019

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Tracy, S. J., Smith, R. F., Wicks, J. K., Fratanduono, D. E., Gleason, A. E., Bolme, C. A., Prakapenka, V. B., Speziale, S., Appel, K., Fernandez-Pañella, A., Lee, H. J., MacKinnon, A., Tavella, F., Eggert, J. H., & Duffy, T. S. (2019). In situ observation of a phase transition in silicon carbide under shock compression using pulsed x-ray diffraction in SITU OBSERVATION of A PHASE ... S. J. TRACY et al. Physical Review B, 99(21), [214106]. https://doi.org/10.1103/PhysRevB.99.214106