Research ArticleAPPLIED PHYSICS

Dynamic fracture of tantalum under extreme tensile stress

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Science Advances  02 Jun 2017:
Vol. 3, no. 6, e1602705
DOI: 10.1126/sciadv.1602705
  • Fig. 1 The pump-probe experiment at SACLA.

    (A) Experimental configuration, where a 5-μm-thick polycrystalline Ta sample is compressed by a pump (optical) laser and the diffraction is observed preferentially in the bcc <001> direction. An ultrafast (7 fs) x-ray beam focused in the z direction probes the lattice arrangement of the sample and generates a Debye-Scherrer ring. (B) A part of the Debye-Scherrer ring is recorded by the multiport charge-coupled device (MPCCD) detector for the bcc (002) plane of Ta at different times during the interaction. All the experimental images have the same color scale.

  • Fig. 2 Experimental profiles of the stretching and postspallation compression in the Ta sample.

    (A) Observation of the stretching in the experiment of the (002) plane of Ta using an azimuthal integration of the diffraction signal obtained onto the MPCCD detector (blue arrow). (B) Observation of the compression wave (purple arrow) due to the relaxation of the tension after spallation in the experiment of the (002) plane of Ta using an azimuthal integration of the diffraction signal obtained onto the MPCCD detector. The onset at the top left corresponds to the maximum stretching of the sample reached at a time t = 1725 ps after the beginning of the interaction, whereas the onset at the top right corresponds to the dynamic fracture of the sample responsible for the generation of a compression wave propagating in the spall layer. The laser comes from the left, and the XFEL probe comes from the right. These illustrations are not to scale.

  • Fig. 3 MD simulation and direct comparison with experimental data.

    (A) Comparison of the diffraction signal obtained from the experiment and simulated by the MD just before spallation, where the stretching of the lattice is the most important at 1725 ps after the beginning of the interaction. The black and red arrows indicate the position of the maximum of the diffraction peaks. (B) Direct comparison between the position of the maximum of the different diffraction peaks in the experiment and in the simulation (t = 0 being defined in the same manner in both cases). (C) Two-dimensional (2D) maps shown in the middle panel corresponding to the spatial distribution of density ρ(x,y) and the longitudinal component of the pressure tensor (Pxx ≡ −σxx) are built by cloning the simulated narrow sample with Ly = 20 nm by a factor of 16. White gaps correspond to pores or voids. For the Pxx map, the green color represents negative pressure and the red color represents positive pressure. The corresponding profiles of density and pressure Pxx at a time of 1925 ps after the beginning of the interaction are displayed in the bottom panel.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/6/e1602705/DC1

    fig. S1. Single-shot x-ray spectra of Ta plasma irradiated by the high-power optical laser.

    fig. S2. Pulse shape of the optical beam at target center chamber.

    fig. S3. Velocity of the Lagrangian particle provided by hydrodynamic (MULTI) modeling.

    fig. S4. Comparison between the new EAM Ta potential and experimental shock Hugoniot curve.

    fig. S5. Shadowgraph of mass distribution after nucleation of first voids in the MD-simulated Ta sample.

    fig. S6. MD simulation of the experiment.

    fig. S7. Determination of the strain rate from the flow velocity profile just before nucleation of the first voids in the MD simulation.

    fig. S8. Determination of the strain rate from the flow velocity profile just before nucleation of the first voids in the MD simulation.

    fig. S9. Direct comparison between experimental profiles and x-ray profiles derived from the MD simulation.

    fig. S10. Experimental determination of the position of the different peaks at t = 1725 ps using the Gaussian method.

    fig. S11. Experimental determination of the position of the different peaks at t = 2125 ps using the Gaussian method.

    fig. S12. Experimental determination of the position of the different peaks at t = 2125 ps using the Lorentzian method.

    fig. S13. Spall strength versus strain rate for tantalum.

    table S1. Pressure and density retrieved from the experimental results at t = 1725 ps displayed in fig. S10.

    table S2. Pressure and density retrieved from the experimental results at t = 2125 ps displayed in fig. S11.

    movie S1. Evolution of density and pressure in the sample given by MD simulation.

    movie S2. Experimental data obtained at SACLA.

    References (3451)

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Single-shot x-ray spectra of Ta plasma irradiated by the high-power optical laser.
    • fig. S2. Pulse shape of the optical beam at target center chamber.
    • fig. S3. Velocity of the Lagrangian particle provided by hydrodynamic (MULTI) modeling.
    • fig. S4. Comparison between the new EAM Ta potential and experimental shock Hugoniot curve.
    • fig. S5. Shadowgraph of mass distribution after nucleation of first voids in the MD-simulated Ta sample.
    • fig. S6. MD simulation of the experiment.
    • fig. S7. Determination of the strain rate from the flow velocity profile just before nucleation of the first voids in the MD simulation.
    • fig. S8. Determination of the strain rate from the flow velocity profile just before nucleation of the first voids in the MD simulation.
    • fig. S9. Direct comparison between experimental profiles and x-ray profiles derived from the MD simulation.
    • fig. S10. Experimental determination of the position of the different peaks at t = 1725 ps using the Gaussian method.
    • fig. S11. Experimental determination of the position of the different peaks at t = 2125 ps using the Gaussian method.
    • fig. S12. Experimental determination of the position of the different peaks at t = 2125 ps using the Lorentzian method.
    • fig. S13. Spall strength versus strain rate for tantalum.
    • table S1. Pressure and density retrieved from the experimental results at t = 1725 ps displayed in fig. S10.
    • table S2. Pressure and density retrieved from the experimental results at t = 2125 ps displayed in fig. S11.
    • References (34–51)

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    Other Supplementary Material for this manuscript includes the following:

    • movie S1 (.avi format). Evolution of density and pressure in the sample given by MD simulation.
    • movie S2 (.avi format). Experimental data obtained at SACLA.

    Download Movies S1 and S2

    Files in this Data Supplement:

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