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

• Published in: Nature communications Vol. 12; no. 1; p. 5474
• Main Authors: Lee, Chanho, Maresca, Francesco, Feng, Rui, Chou, Yi, Ungar, T., Widom, Michael, An, Ke, Poplawsky, Jonathan D., Chou, Yi-Chia, Liaw, Peter K., Curtin, W. A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16.09.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 147/143; 639/166/988; 639/301/1023/303; 639/301/1034/1037; Alloys; BCC metals; Body temperature; Chromium; Computational methods; Dislocation mobility; Edge dislocations; Electron microscopes; Energy efficiency; Entropy; High entropy alloys; High resolution electron microscopy; High strength alloys; High temperature; Humanities and Social Sciences; MATERIALS SCIENCE; Mechanical engineering; Mechanical properties; Metals; Molybdenum; multidisciplinary; Niobium; Plastic flow; Science; Science (multidisciplinary); Screw dislocations; Titanium; Transmission electron microscopy; Tungsten; Zirconium
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25807-w

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 10 7 BCC HEAs and identify over 10 6 possible ultra-strong high-T alloy compositions for future exploration. The strength in BCC high-entropy alloys is associated with the type of mobile dislocations. Here the authors demonstrate by means of an ample array of experimental techniques that edge dislocations can control the strength of BCC high-entropy alloys.