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Title: Understanding of the Elemental Diffusion Behavior in Concentrated Solid Solution Alloys

As one of the core effects on the high-temperature structural stability, the so-called “sluggish diffusion effect” in high-entropy alloy (HEA) has attracted much attention. Experimental investigations on the diffusion kinetics have been carried out in a few HEA systems, such as Al-Co-Cr-Fe-Ni and Co-Cr-Fe-Mn-Ni. However, the mechanisms behind this effect remain unclear. To better understand the diffusion kinetics of the HEAs, a combined computational/experimental approach is employed in the current study. In the present work, a self-consistent atomic mobility database is developed for the face-centered cubic (fcc) phase of the Co-Cr-Fe-Mn-Ni quinary system. The simulated diffusion coefficients and concentration profiles using this database can well describe the experimental data both from this work and the literatures. The validated mobility database is then used to calculate the tracer diffusion coefficients of Ni in the subsystems of the Co-Cr-Fe-Mn-Ni system with equiatomic ratios. The comparisons of these calculated diffusion coefficients reveal that the diffusion of Ni is not inevitably more sluggish with increasing number of components in the subsystem even with homologous temperature. Taking advantage of computational thermodynamics, the diffusivities of alloying elements with composition and/or temperature are also calculated. Furthermore, these calculations provide us an overall picture of the diffusion kineticsmore » within the Co-Cr-Fe-Mn-Ni system.« less
Authors:
 [1] ;  [1] ; ORCiD logo [2] ; ORCiD logo [2] ;  [1] ;  [1] ;  [1] ;  [1]
  1. CompuTherm LLC, Middleton, WI (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Phase Equilibria and Diffusion
Additional Journal Information:
Journal Volume: 38; Journal Issue: 4; Journal ID: ISSN 1547-7037
Publisher:
ASM International
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Energy Dissipation to Defect Evolution (EDDE)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; atomic mobility database; CALPHAD; computational thermodynamics; high entropy alloy; sluggish diffusivity; solid solution alloy
OSTI Identifier:
1400198