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Title: Effects of non-hydrostaticity and grain size on the pressure-induced phase transition of the CoCrFeMnNi high-entropy alloy

Journal Article · · Journal of Applied Physics
DOI: https://doi.org/10.1063/1.5046180 · OSTI ID:1542318
ORCiD logo [1]; ORCiD logo [2];  [2];  [2];  [2];  [3];  [4];  [4];  [4]; ORCiD logo [2]
  1. Univ. of Science and Technology Beijing, Beijing (China); Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai (China)
  2. Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai (China)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Univ. of California, Santa Cruz, CA (United States). Dept. of Earth and Planetary Sciences
  4. Univ. of Science and Technology Beijing, Beijing (China)

Recently, an irreversible polymorphic transition from face-centered cubic to hexagonal close-packing was surprisingly observed under high pressure in the prototype CoCrFeMnNi high-entropy alloys (HEAs) by various research groups. This unexpected phase transition brings new insights into the stability of HEAs, and its irreversibility stimulates exploration for new HEAs via high-pressure compression synthesis. However, the onset pressure for the phase transition was reported to fluctuate over a vast range from ~7 to above 49 GPa in the reported experiments. The reason for this inconsistency remains unclear and puzzles the HEA community. To address this problem, this work systematically investigates the effects of non-hydrostaticity and grain size. Our results demonstrate that larger deviatoric stress induced by the non-hydrostaticity of the pressure medium and larger grain size of the initial sample can both promote a phase transition and, therefore, considerably depress the onset pressure.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC); USDOE
Grant/Contract Number:
AC02-05CH11231; FG02-94ER14466; AC02-06CH11357
OSTI ID:
1542318
Alternate ID(s):
OSTI ID: 1471259
Journal Information:
Journal of Applied Physics, Vol. 124, Issue 11; ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

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Cited By (4)

Anomalous Evolution of Strength and Microstructure of High‐Entropy Alloy CoCrFeNiMn after High‐Pressure Torsion at 300 and 77 K journal August 2019
Element Effects on High-Entropy Alloy Vacancy and Heterogeneous Lattice Distortion Subjected to Quasi-equilibrium Heating journal October 2019
High-Pressure Induced Phase Transitions in High-Entropy Alloys: A Review journal March 2019
Element Effects on High-Entropy Alloy Vacancy and Heterogeneous Lattice Distortion Subjected to Quasi-equilibrium Heating journal October 2019

Figures / Tables (4)