Pressure-induced fcc to hcp phase transition in Ni-based high entropy solid solution alloys
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Division of Materials Science and Technology
- Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab., High Pressure Collaborative Access Team (HPCAT)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
- 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
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.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- AC05-00OR22725; NA0001974; FG02-99ER45775; AC02-06CH11357
- OSTI ID:
- 1338551
- Journal Information:
- Applied Physics Letters, Vol. 110, Issue 1; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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