High pressure phase transition and strength estimate in polycrystalline alumina during laser-driven shock compression

Anirudh Hari, Rohit Hari, Patrick G. Heighway, Raymond F. Smith, Thomas S. Duffy, Melissa Sims, Saransh Singh, Dayne E. Fratanduono, Cynthia A. Bolme, Arianna E. Gleason, Federica Coppari, Hae Ja Lee, Eduardo Granados, Philip Heimann, Jon H. Eggert, June K. Wicks

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Alumina (Al2O3) is an important ceramic material notable for its compressive strength and hardness. It represents one of the major oxide components of the Earth’s mantle. Static compression experiments have reported evidence for phase transformations from the trigonal α-corundum phase to the orthorhombic Rh2O3(II)-type structure at ∼90 GPa, and then to the post-perovskite structure at ∼130 GPa, but these phases have yet to be directly observed under shock compression. In this work, we describe laser-driven shock compression experiments on polycrystalline alumina conducted at the Matter in Extreme Conditions endstation of the Linac Coherent Light Source. Ultrafast x-ray pulses (50 fs, 1012 photons/pulse) were used to probe the atomic-level response at different times during shock propagation and subsequent pressure release. At 107 ± 8 GPa on the Hugoniot, we observe diffraction peaks that match the orthorhombic Rh2O3(II) phase with a density of 5.16 ± 0.03 g cm−3. Upon unloading, the material transforms back to the α-corundum structure. Upon release to ambient pressure, densities are lower than predicted assuming isentropic release, indicating additional lattice expansion due to plastic work heating. Using temperature values calculated from density measurements, we provide an estimate of alumina’s strength on release from shock compression.

Original languageEnglish (US)
Article number094002
JournalJournal of Physics Condensed Matter
Volume35
Issue number9
DOIs
StatePublished - Mar 8 2023

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • General Materials Science

Keywords

  • alumina
  • laser compression
  • megabar
  • sapphire
  • shock compression
  • strength
  • x-ray free electron laser

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