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Lattice-Distortion-Enhanced Yield Strength in a Refractory High-Entropy Alloy |
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| Authors: | Chanho Lee Yi Chou George Kim Michael C. Gao Ke An Jamieson Brechtl Chuan Zhang Wei Chen Jonathan D. Poplawsky Gian Song Yang Ren Yi-Chia Chou Peter K. Liaw |
| Affiliation: | 1. 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;2. Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010 Taiwan;3. Department of Mechanical, Materials, and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL, 60616 USA;4. National Energy Technology Laboratory/Leidos Research Support Team, Albany, OR, 97321 USA;5. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831 USA;6. Energy and Transportation Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831 USA;7. Computherm LLC, 8401 Greenway Blvd, Middleton, WI, 53562 USA;8. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831 USA;9. Division of Advanced Materials Engineering and Institute for Rare Metals, Kongju National University, Cheonan, Chungnam, 330-717 Republic of Korea;10. X-ray Science Division, Argonne National Laboratory, Lemont, IL, 60439 USA;11. Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, 37996-2100 USA |
| Abstract: | Severe distortion is one of the four core effects in single-phase high-entropy alloys (HEAs) and contributes significantly to the yield strength. However, the connection between the atomic-scale lattice distortion and macro-scale mechanical properties through experimental verification has yet to be fully achieved, owing to two critical challenges: 1) the difficulty in the development of homogeneous single-phase solid-solution HEAs and 2) the ambiguity in describing the lattice distortion and related measurements and calculations. A single-phase body-centered-cubic (BCC) refractory HEA, NbTaTiVZr, using thermodynamic modeling coupled with experimental verifications, is developed. Compared to the previously developed single-phase NbTaTiV HEA, the NbTaTiVZr HEA shows a higher yield strength and comparable plasticity. The increase in yield strength is systematically and quantitatively studied in terms of lattice distortion using a theoretical model, first-principles calculations, synchrotron X-ray/neutron diffraction, atom-probe tomography, and scanning transmission electron microscopy techniques. These results demonstrate that severe lattice distortion is a core factor for developing high strengths in refractory HEAs. |
| Keywords: | alloy-design strategies lattice distortion microstructure NbTaTiVZr refractory high-entropy alloys yield strength |
