Strength can be controlled by edge dislocations in refractory high-entropy alloys

Chanho Lee; Francesco Maresca; Rui Feng; Yi Chou; T Ungar; Michael Widom; Ke An; Jonathan D Poplawsky; Yi-Chia Chou; Peter K Liaw; W A Curtin

doi:10.1038/s41467-021-25807-w

Strength can be controlled by edge dislocations in refractory high-entropy alloys

Nat Commun. 2021 Sep 16;12(1):5474. doi: 10.1038/s41467-021-25807-w.

Authors

Chanho Lee^#^{1

2}, Francesco Maresca^#^{3

4}, Rui Feng^#^{1

5}, Yi Chou⁶, T Ungar⁷, Michael Widom⁸, Ke An⁵, Jonathan D Poplawsky⁹, Yi-Chia Chou⁶, Peter K Liaw¹⁰, W A Curtin¹¹

Affiliations

¹ Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, 37996-2100, USA.
² Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
³ Engineering and Technology Institute (ENTEG), Faculty of Science and Engineering, University of Groningen, Groningen, 9747AG, Netherlands. f.maresca@rug.nl.
⁴ Laboratory for Multiscale Mechanics Modeling, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland. f.maresca@rug.nl.
⁵ Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
⁶ Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
⁷ Department of Materials Physics, Eötvös University, Budapest, P.O. Box 32, H-1518, Hungary.
⁸ Department of Physics, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
⁹ Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
¹⁰ Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, 37996-2100, USA. pliaw@utk.edu.
¹¹ Laboratory for Multiscale Mechanics Modeling, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.

^# Contributed equally.

Abstract

Energy efficiency is motivating the search for new high-temperature (high-T) metals. Some new body-centered-cubic (BCC) random multicomponent "high-entropy alloys (HEAs)" based on refractory elements (Cr-Mo-Nb-Ta-V-W-Hf-Ti-Zr) possess exceptional strengths at high temperatures but the physical origins of this outstanding behavior are not known. Here we show, using integrated in-situ neutron-diffraction (ND), high-resolution transmission electron microscopy (HRTEM), and recent theory, that the high strength and strength retention of a NbTaTiV alloy and a high-strength/low-density CrMoNbV alloy are attributable to edge dislocations. This finding is surprising because plastic flows in BCC elemental metals and dilute alloys are generally controlled by screw dislocations. We use the insight and theory to perform a computationally-guided search over 10⁷ BCC HEAs and identify over 10⁶ possible ultra-strong high-T alloy compositions for future exploration.