Thermodynamic Assessment of the Al-Cr System by Combining the First Principles and CALPHAD Methods

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Thermodynamic assessment of the Al-Cr system has been carried out by incorporating first-principles calculations into the CALPHAD approach. A regular solution approximation was adopted to describe the Gibbs energy of the solution phases. The several phases appearing in the composition range between about 30 and 42 at.%Cr were treated as a single homogeneous γ-phase, based on recent experimental results, and the Gibbs energy of the γ-phase was represented using the four-sublattice model with the formula (Al,Cr)8(Al,Cr)8(Cr)12(Al)24. The calculated results enable the reproduction of experimental results on both the phase equilibria and thermochemical properties. In addition, a B2 ordered bcc phase, which was suggested to form as an equilibrium phase in a previous X-ray diffraction study, is not likely to form in either the stable state or metastable state based on our first-principles calculations.

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Materials Science Forum (Volumes 539-543)

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Edited by:

T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran

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2407-2412

Citation:

T. Tokunaga et al., "Thermodynamic Assessment of the Al-Cr System by Combining the First Principles and CALPHAD Methods", Materials Science Forum, Vols. 539-543, pp. 2407-2412, 2007

Online since:

March 2007

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