Abstract
We applied Simmons–Balluffi methods, positron measurements, and neutron diffraction to estimate the vacancy of CoCrFeNi and CoCrFeMnNi high-entropy alloys (HEAs) using Cu as a benchmark. The corresponding formation enthalpies and associated entropies of the HEAs and Cu were calculated. The vacancy-dependent effective free volumes in both CoCrFeNi and CoCrFeMnNi alloys are greater than those in Cu, implying the easier formation of vacancies by lattice structure relaxation of HEAs at elevated temperatures. Spatially resolved synchrotron X-ray measurements revealed different characteristics of CoCrFeNi and CoCrFeMnNi HEAs subjected to quasi-equilibrium conditions at high temperatures. Element-dependent behavior revealed by X-ray fluorescence (XRF) mapping indicates the effect of Mn on the Cantor Alloy.
| Original language | English |
|---|---|
| Article number | 14788 |
| Journal | Scientific Reports |
| Volume | 9 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2019 |
| Externally published | Yes |
Funding
The authors thank the R&D Center for Membrane Technology, Chung Yuan University, for positron annihilation measurements. Research conducted at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, United States Department of Energy. The authors are immensely grateful for the financial support of the National Synchrotron Radiation Research Center (NSRRC) and the Ministry of Science and Technology (MOST) programs (107-2628-E-009-001-MY3, 107-2218-E-007-012, and 108-2221-E-009-131-MY4). This work was financially supported by the “High Entropy Materials Center” from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) and from Project MOST 107-3017-F-007-003 by MOST in Taiwan. E.W.H. and K.N.T. thank the “Center for Semiconductor Technology Research” from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the MOE in Taiwan. This work was also supported in part by MOST, Taiwan, under grants MOST-107-3017-F-009-002 and MOST-108-3017-F-009-003.