Thermodynamic modeling of fcc order/disorder transformations in the CoPt system

Dongeung Kim, James E. Saal, Liangcai Zhou, Shunli Shang, Yong Du, Zi-kui Liu

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

The present work reports on a thermodynamic modeling of the CoPt system with ordered fcc phases of L10 and L12 structures by means of the CALPHAD method. The liquid, hcp and fcc phases have been modeled as substitutional solutions where the interaction parameters are composition dependent in the form of the RedlichKister polynomial. The disordered and ordered fcc phases have been modeled in terms of the compound energy formalism with a single Gibbs energy function. The obtained phase equilibria and activities of Co and Pt agree well with the available experimental data. First-principles calculations are performed to obtain the enthalpies of formation for the ordered fcc phases at 0 K. These calculated enthalpies of formations for the ordered phases are less negative than the enthalpies of the disordered state at low temperatures determined from the CALPHAD modeling. The FePt and NiPt systems exhibit the same feature as that in the CoPt system, which is discussed in terms of the total magnetic moment of ordered fcc phases.

Original languageEnglish (US)
Pages (from-to)323-330
Number of pages8
JournalCalphad: Computer Coupling of Phase Diagrams and Thermochemistry
Volume35
Issue number3
DOIs
StatePublished - Sep 1 2011

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Computer Science Applications

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