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Title: Thermodynamics of concentrated solid solution alloys

This study reviews the three main approaches for predicting the formation of concentrated solid solution alloys (CSSA) and for modeling their thermodynamic properties, in particular, utilizing the methodologies of empirical thermo-physical parameters, CALPHAD method, and first-principles calculations combined with hybrid Monte Carlo/Molecular Dynamics (MC/MD) simulations. In order to speed up CSSA development, a variety of empirical parameters based on Hume-Rothery rules have been developed. Herein, these parameters have been systematically and critically evaluated for their efficiency in predicting solid solution formation. The phase stability of representative CSSA systems is then illustrated from the perspectives of phase diagrams and nucleation driving force plots of the σ phase using CALPHAD method. The temperature-dependent total entropies of the FCC, BCC, HCP, and σ phases in equimolar compositions of various systems are presented next, followed by the thermodynamic properties of mixing of the BCC phase in Al-containing and Ti-containing refractory metal systems. First-principles calculations on model FCC, BCC and HCP CSSA reveal the presence of both positive and negative vibrational entropies of mixing, while the calculated electronic entropies of mixing are negligible. Temperature dependent configurational entropy is determined from the atomic structures obtained from MC/MD simulations. Current status and challenges in using these methodologiesmore » as they pertain to thermodynamic property analysis and CSSA design are discussed.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [4] ;  [5]
  1. National Energy Technology Lab. (NETL), Albany, OR (United States); AECOM, Albany, OR (United States)
  2. CompuTherm LLC, Middleton, WI (United States)
  3. Tennessee State Univ., Nashville, TN (United States)
  4. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  5. National Energy Technology Lab. (NETL), Albany, OR (United States)
Publication Date:
Report Number(s):
CONTR-PUB-247
Journal ID: ISSN 1359-0286; PII: S1359028616302029
Grant/Contract Number:
FE0004000
Type:
Accepted Manuscript
Journal Name:
Current Opinion in Solid State and Materials Science
Additional Journal Information:
Journal Volume: 21; Journal Issue: 5; Journal ID: ISSN 1359-0286
Publisher:
Elsevier
Research Org:
National Energy Technology Lab. (NETL), Albany, OR (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1439969