Exceptionally high spallation strength for a high-entropy alloy demonstrated by experiments and simulations

D Thurmer and ST Zhao and OR Deluigi and C Stan and IA Alhafez and HM Urbassek and MA Meyers and EM Bringa and N Gunkelmann, JOURNAL OF ALLOYS AND COMPOUNDS, 895, 162567 (2022).

DOI: 10.1016/j.jallcom.2021.162567

High-entropy alloys are materials with an increasing number of technological applications. Amongst them, the Cantor alloy, FeMnCoCrNi, shows desirable mechanical properties at normal loading conditions. In this study we focus on the performance of the Cantor alloy at the ultra- high deformation rates of shock waves. We study shock-induced spallation using both experiments and atomistic simulations. Experimental loading is achieved using high power laser, with VISAR to obtain velocity profiles and spall strength, followed by transmission electron microscopy of the recovered samples. Molecular Dynamics (MD) simulations of shock-induced spallation are compared with experiments. Both experiments and simulations show a high spall strength which would be beneficial for certain applications, with experiments giving similar to 8 GPa at similar to 10(7)s(-1) and MD giving almost similar to 30 GPa at similar to 10(9)s(-1). The difference between experiments and simulations can be explained by the difference in strain rate. Post- mortem analysis of the experimental samples shows nanotwins near the spall plane, while MD simulations show a highly disordered region giving rise to void nucleation and spall during loading. (C) 2021 Elsevier B.V. All rights reserved.

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