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Title: Pressure-induced fcc to hcp phase transition in Ni-based high entropy solid solution alloys

In this research, pressure-induced phase transition from the fcc to a hexagonal close-packed (hcp) structure wasfound in NiCoCrFe solid solution alloy starting at 13.5 GPa. The phase transition is very sluggish and the transition did not complete at ~ 40 GPa. The hcp structure is quenchable to ambient pressure. Only a very small amount (<5%) of hcp phase was found in the isostructural NiCoCr ternary alloy up to the pressure of 45 GPa and no obvious hcp phase was found in NiCoCrFePd system till to 74 GPa. Ab initio Gibbs free energy calculations indicated the energy differences between the fcc and the hcp phases for the three alloys are very small, but they are sensitive to temperature. Finally, the critical transition pressure in NiCoCrFe varies from 1 GPa at room temperature to 6 GPa at 500 K.
Authors:
 [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [2] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [4] ;  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Division of Materials Science and Technology
  2. Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab., High Pressure Collaborative Access Team (HPCAT)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Division of Materials Science and Technology; Univ. of Tennessee, Knoxville, TN (United States). Department of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
AC05-00OR22725; NA0001974; FG02-99ER45775; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 110; Journal Issue: 1; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Ni-based solid solution alloys; phase transformation; high pressure; x-ray diffraction
OSTI Identifier:
1338551