First-principles calculations, experimental study, and thermodynamic modeling of the Al-Co-Cr system

Xuan L Liu; Thomas Gheno; Bonnie B Lindahl; Greta Lindwall; Brian Gleeson; Zi-Kui Liu

doi:10.1371/journal.pone.0121386

First-principles calculations, experimental study, and thermodynamic modeling of the Al-Co-Cr system

PLoS One. 2015 Apr 13;10(4):e0121386. doi: 10.1371/journal.pone.0121386. eCollection 2015.

Authors

Xuan L Liu¹, Thomas Gheno², Bonnie B Lindahl³, Greta Lindwall¹, Brian Gleeson², Zi-Kui Liu¹

Affiliations

¹ Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States of America.
² Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, United States of America.
³ Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44, Stockholm, Sweden.

Abstract

The phase relations and thermodynamic properties of the condensed Al-Co-Cr ternary alloy system are investigated using first-principles calculations based on density functional theory (DFT) and phase-equilibria experiments that led to X-ray diffraction (XRD) and electron probe micro-analysis (EPMA) measurements. A thermodynamic description is developed by means of the calculations of phase diagrams (CALPHAD) method using experimental and computational data from the present work and the literature. Emphasis is placed on modeling the bcc-A2, B2, fcc-γ, and tetragonal-σ phases in the temperature range of 1173 to 1623 K. Liquid, bcc-A2 and fcc-γ phases are modeled using substitutional solution descriptions. First-principles special quasirandom structures (SQS) calculations predict a large bcc-A2 (disordered)/B2 (ordered) miscibility gap, in agreement with experiments. A partitioning model is then used for the A2/B2 phase to effectively describe the order-disorder transitions. The critically assessed thermodynamic description describes all phase equilibria data well. A2/B2 transitions are also shown to agree well with previous experimental findings.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Alloys / chemistry*
Aluminum / chemistry*
Chromium / chemistry*
Cobalt / chemistry*
Models, Chemical
Phase Transition
Thermodynamics*
X-Ray Diffraction

Substances

Alloys
Chromium
Cobalt
Aluminum

Grants and funding

XLL, GL, and ZKL acknowledges that the computational aspects of this work were financially supported by the NSF Industry/University Cooperative Research Center for Computational Materials Design (CCMD, http://www.ccmd.psu.edu/), including dues contributions of CCMD members, through grants IIP-1034965 (Penn State) and IIP-1034968 (Georgia Tech) and the Office of Naval Research (ONR, http://www.onr.navy.mil/) with the contract number N0014-07-1-0638 managed by David Shifler. TG and BG acknowledges that the experimental aspects of this work were partly supported by the Department of Energy under grant number DE-FE0007271 through the University Turbine Systems Research (UTSR) Program run by the National Energy Technology Laboratory (NTEL, http://www.netl.doe.gov/), with Dr. Seth Lawson being the Project Manager. One of the authors, BL, acknowledges funding from the European Research Fund for Coal and Steel (RFCS, http://cordis.europa.eu/coal-steel-rtd/) project “Precipitation in High Manganese Steels” under the grant agreement no. RFSR-CT-2010-00018. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.