High Pressure

Phase transition mechanisms

Post-Image

Figure 1: Microstructure induced by the alpha-epsilon transformation in iron under pressure measured with X-ray tomography, Boulard et al., Acta Materialia 192, 30-39 (2020)

Phase transition mechanisms

Solid-solid phase transitions are complex phenomena that span several length and time scales, from the local rearrangement of atoms to the evolutions in the microstructure of the material. The research conducted in the laboratory aims at elucidating:

  • The sequence of local mechanisms that drives the transition between phases ;
  • The characteristic time response of transformations under dynamic loadings ;
  • The impact of loading rate on deviations with respect to the equilibrium phase diagram and on the introduction of a competition between deformation mechanisms. The exploration of the wide range of time and length scales of interest relies on a synergetic use of experimental (synchrotron radiation, static/dynamic diamond anvil cells, large volume presses, laser shock) and numerical (ab initio calculations, molecular dynamics, continuum mechanics) tools.
Deformation and nucleation of twins in a TATB polycrystal under shock loading, Lafourcade et al., Physical Review Materials 3, 053610 (2019)

Figure 2:

Deformation and nucleation of twins in a TATB polycrystal under shock loading, Lafourcade et al., Physical Review Materials 3, 053610 (2019)

Contour plot of integrated X-ray diffraction images collected at the β-γ phase transition in tin at a compression rate of ~10 GPa/ms using a dynamic diamond anvil cell.

Figure 3:

Contour plot of integrated X-ray diffraction images collected at the β-γ phase transition in tin at a compression rate of ~10 GPa/ms using a dynamic diamond anvil cell.

Publications

  1. B. Dupé, B. Amadon, Y.-P. Pellegrini, C. Denoual, Mechanism for the α-ε phase transition in iron, Phys. Rev. B 87, 024103 (2013) DOI
  2. A. Dewaele, C. Denoual, S. Anzellini, F. Occelli, M. Mezouar, P. Cordier, S. Merkel, M. Véron, E. Rausch, Mechanism of the α-ε phase transformation in iron, Phys. Rev. B 91, 174105 (2015) DOI
  3. C. Pépin, A. Sollier, A. Marizy, F. Occelli, M. Sander, R. Torchio, P. Loubeyre, Kinetics and structural changes in dynamically compressed bismuth, Phys. Rev. B. 100, 060101 (2019) DOI
  4. L. Soulard and O. Durand, Observation of phase transitions in shocked tin by molecular dynamics, J. App. Phys. 127, 165901 (2020) DOI
  5. C. Pépin, R. Torchio, F. Occelli, E. Lescoute, O. Mathon, V. Recoules, J. Bouchet, L. Videau, A. Benuzzi-Mounaix, T. Vinci, R. Briggs, S. Pascarelli, R. Gaal, P. Loubeyre and A. Sollier, White-line evolution in shocked solid Ta evidenced by synchrotron x-ray absorption spectroscopy, Phys. Rev. B 102, 144102 (2020) DOI
  6. N. Bruzy, C. Denoual, A. Vattré, Polyphase crystal plasticity for high strain rate: Application to twinning and retwinning and tantalum, J. Mech. Phys. Sol. 166, 104921 (2022) DOI

Researchers involved

B. Amadon, E. Barraud, R. Béjaud, N. Bruzy, C. Denoual, A. Dewaele, T. Géral, B. Jodar, P. Lafourcade, P. Loubeyre, J.-B. Maillet, F. Occelli, Y.-P. Pellegrini, C. Pépin, V. Recoules, A. Sollier, L. Soulard, L. Toraille, L. Videau