A study about shock-induced spallation in mono- and nanocrystalline high-entropy alloys

ORAL

Abstract

High-entropy alloys are highly attractive for future applications in the technical field thanks to their incredible potential regarding mechanical properties. Although they are increasingly sparking interest for future usage, their general understanding is not yet complete. To further understand high-entropy alloys and their capabilites, we studied the influence of shock-induced spallation on mono- and nanocrystalline high-entropy alloys with varying grain sizes. The monocrystalline sample shows high spall strength and was compared to experiments that also showed high spall strengths. The nanocrystalline high-entropy alloy samples also show high spall strength, but the spall strength is lower compared to the monocrystalline sample. While our monocrystalline high-entropy alloy shows an amorphous region giving rise to void nucleation and spall during loading, our nanocrystalline high-entropy alloy samples show a high amount of stacking faults, twins and dislocations during shock. These even persist during the release of the shock wave. This is in good agreement with earlier shock loading experiments using high power lasers where nanotwinning has been observed in the recovered samples.

*Daniel Thürmer and Nina Merkert (née Gunkelmann) greatly appreciate the financial support from Simulation Science Center Clausthal / Göttingen.Eduardo M. Bringa and Orlando Deluigi thank support from UNCuyo SIIP grant 06/M035, and from PICTO-UUMM-2019-00048.Iyad Alabd Alhafez and Herbert M. Urbassek acknowledge funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - project number 172116086 - SFB 926 and computation at the High Performance Cluster Elwetritsch (RHRK, TU Kaiserslautern, Germany).The experimental portion was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and is identified as LLNL-JRNL-825521.

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Publication: https://doi.org/10.1063/5.0082199 "Shock-induced spallation in a nanocrystalline high-entropy alloy: An atomistic study"

https://doi.org/10.1016/j.jallcom.2021.162567 "Exceptionally high spallation strength for a high-entropy alloy demonstrated by experiments and simulations"

Presenters

  • Daniel Thürmer

Authors

  • Daniel Thürmer

  • Nina Merkert (née Gunkelmann)

    • Clausthal University of Technology, Institute of Applied Mechanics

  • Shiteng Zhao

    • Beihang University, School of Material Science and Engineering

  • Orlando R Deluigi

    • University of Mendoza, CONICET and Faculty of Engineering
    • Universidad de Mendoza

  • Camelia V Stan

    • Lawrence Livermore Natl Lab

  • Iyad A Alhafez

    • University Kaiserslautern, Physics Department and Research Center OPTIMAS

  • Herbert M Urbassek

    • University Kaiserslautern, Physics Department and Research Center OPTIMAS

  • Marc A Meyers

    • University of California, San Diego

  • Eduardo M Bringa

    • University of Mendoza, CONICET and Faculty of Engineering
    • Universidad de Mendoza