Lattice-Distortion-Enhanced Yield Strength in a Refractory High-Entropy Alloy
Journal
Advanced Materials
Journal Volume
32
Journal Issue
49
Date Issued
2020
Author(s)
Lee C.; Chou Y.-C.
DOI
ADVME
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. © 2020 Wiley-VCH GmbH
Subjects
Calculations; Entropy; High resolution transmission electron microscopy; Refractory materials; Scanning electron microscopy; Yield stress; Atom probe tomography; Body-centered cubic; Experimental verification; First-principles calculation; Lattice distortions; Scanning transmission electron microscopy; Theoretical modeling; Thermodynamic model; High-entropy alloys
Publisher
Wiley-VCH Verlag
Type
journal article