Hidden Effects of Negative Stacking Fault Energies in Complex Concentrated Alloys

Zongrui Pei; Biswanath Dutta; Fritz Körmann; Mingwei Chen

doi:10.1103/PhysRevLett.126.255502

Hidden Effects of Negative Stacking Fault Energies in Complex Concentrated Alloys

Phys Rev Lett. 2021 Jun 25;126(25):255502. doi: 10.1103/PhysRevLett.126.255502.

Authors

Zongrui Pei¹, Biswanath Dutta², Fritz Körmann³, Mingwei Chen⁴

Affiliations

¹ Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
² Department of Materials Science and Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands.
³ Department of Materials Science and Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands and Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH, D-40237 Düsseldorf, Germany.
⁴ Department of Materials Science and Engineering and Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, Maryland 21218, USA.

PMID: 34241525
DOI: 10.1103/PhysRevLett.126.255502

Abstract

Negative stacking fault energies (SFEs) are found in face-centered cubic high-entropy alloys with excellent mechanical properties, especially at low temperatures. Their roles remain elusive due to the lack of in situ observation of nanoscale deformation. Here, the polymorphism of Shockley partials is fully explored, assisted by a new method. We show negative SFEs result in novel partial pairs as if they were in hexagonal close-packed alloys. The associated yield stresses are much higher than those for other mechanisms at low temperatures. This generalizes the physical picture for all negative-SFE alloys.