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
Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, 37996-2100, USA.
Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
Nat Commun. 2021 Sep 16;12(1):5474. 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 BCC HEAs and identify over 10 possible ultra-strong high-T alloy compositions for future exploration.
能源效率推动了对新型高温金属的探索。一些基于难熔元素（Cr-Mo-Nb-Ta-V-W-Hf-Ti-Zr）的新型体心立方（BCC）随机多组分“高熵合金（HEA）”在高温下具有出色的强度，但这种优异性能的物理根源尚不清楚。在此，我们通过结合原位中子衍射（ND）、高分辨率透射电子显微镜（HRTEM）以及近期的理论研究表明，NbTaTiV合金和高强度/低密度CrMoNbV合金的高强度及强度保持性归因于刃型位错。这一发现令人惊讶，因为BCC元素金属和稀合金中的塑性流动通常由螺型位错控制。我们利用这一见解和理论对10种BCC高熵合金进行了计算引导搜索，并确定了10多种可能的超强高温合金成分以供未来探索。
