skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

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

Abstract

A pressure-induced phase transition from the fcc to a hexagonal close-packed (hcp) structure was found 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. The critical transition pressure in NiCoCrFe varies from ~1 GPa at room temperature to ~6 GPa at 500 K.

Authors:
; ; ; ; ; ; ; ;  [1];  [2];  [2]
  1. Tennessee-K
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1338997
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 110; Journal Issue: 1
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE

Citation Formats

Zhang, F. X., Zhao, Shijun, Jin, Ke, Bei, H., Popov, D., Park, Changyong, Neuefeind, J. C., Weber, W. J., Zhang, Yanwen, ORNL), and CIW). Pressure-induced fcc to hcp phase transition in Ni-based high entropy solid solution alloys. United States: N. p., 2017. Web. doi:10.1063/1.4973627.
Zhang, F. X., Zhao, Shijun, Jin, Ke, Bei, H., Popov, D., Park, Changyong, Neuefeind, J. C., Weber, W. J., Zhang, Yanwen, ORNL), & CIW). Pressure-induced fcc to hcp phase transition in Ni-based high entropy solid solution alloys. United States. doi:10.1063/1.4973627.
Zhang, F. X., Zhao, Shijun, Jin, Ke, Bei, H., Popov, D., Park, Changyong, Neuefeind, J. C., Weber, W. J., Zhang, Yanwen, ORNL), and CIW). Wed . "Pressure-induced fcc to hcp phase transition in Ni-based high entropy solid solution alloys". United States. doi:10.1063/1.4973627.
@article{osti_1338997,
title = {Pressure-induced fcc to hcp phase transition in Ni-based high entropy solid solution alloys},
author = {Zhang, F. X. and Zhao, Shijun and Jin, Ke and Bei, H. and Popov, D. and Park, Changyong and Neuefeind, J. C. and Weber, W. J. and Zhang, Yanwen and ORNL) and CIW)},
abstractNote = {A pressure-induced phase transition from the fcc to a hexagonal close-packed (hcp) structure was found 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. The critical transition pressure in NiCoCrFe varies from ~1 GPa at room temperature to ~6 GPa at 500 K.},
doi = {10.1063/1.4973627},
journal = {Applied Physics Letters},
number = 1,
volume = 110,
place = {United States},
year = {Wed Jan 04 00:00:00 EST 2017},
month = {Wed Jan 04 00:00:00 EST 2017}
}
  • 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 fccmore » 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.« less
  • The entropy contributions to the relative stability of one crystal structure versus another due to electronic excitations are calculated in lowest order. While the electronic contribution is but a small part of the total entropy of a crystal, the change in these terms with change in structure is as large as the entropy changes inferred from experiment. One will not have a complete accounting of such entropy effects until there are detailed estimates of the phonon contributions. However, the present results offer the possibility of dividing the experimental values into electronic and phonon terms and attributing to each the temperaturemore » dependence of their leading terms when doing thermodynamic calculations.« less
  • The results of x-ray diffraction studies on 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} solid solution poled at various electric fields are presented. After poling, significant value of planar electromechanical coupling coefficient (k{sub P}) is observed for this composition having cubic structure in unpoled state. The cubic structure of 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} transforms to monoclinic structure with space group Pm for the poling field ≥5 kV/cm. Large c-axis microscopic lattice strain (1.6%) is achieved at 30 kV/cm poling field. The variation of the c-axis strain and unit cell volume with poling field shows a drastic jump similar to that observed for strainmore » versus electric field curve in (1 − x)Pb(Mg{sub 1/3}Nb{sub 2/3}) O{sub 3}-xPbTiO{sub 3} and (1 − x)Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3}.« less
  • In order to explore the chemical effects on radiation response of alloys with multi-principal elements, defect evolution under Au ion irradiation was investigated in the elemental Ni, equiatomic NiCo and NiFe alloys. Single crystals were successfully grown in an optical floating zone furnace and their (100) surfaces were irradiated with 3 MeV Au ions at fluences ranging from 1 × 10 13 to 5 × 10 15 ions cm –2 at room temperature. The irradiation-induced defect evolution was analyzed by using ion channeling technique. Experiment shows that NiFe is more irradiation-resistant than NiCo and pure Ni at low fluences. Withmore » continuously increasing the ion fluences, damage level is eventually saturated for all materials but at different dose levels. The saturation level in pure Ni appears at relatively lower irradiation fluence than the alloys, suggesting that damage accumulation slows down in the alloys. Here, under high-fluence irradiations, pure Ni has wider damage ranges than the alloys, indicating that defects in pure Ni have high mobility.« less