J-C Crivello and J-M Joubert 2010 J. Phys.: Condens. Matter 22 035402 doi:10.1088/0953-8984/22/3/035402
J-C Crivello and J-M Joubert
Show affiliationsThe total energies of all the ordered configurations of the σ and χ phases have been calculated by using first principles methodology in both Mo–Re and W–Re systems. These two complex structures possess 5 and 4 inequivalent sites generating 32 and 16 different ordered configurations, respectively, for a binary A–B system. The converged total energies of all the fully relaxed structures have been used to compute the occupancy of the inequivalent sites as a function of composition and temperature by using the Bragg–Williams approximation in the complete composition range. It is shown that the configurational entropy stabilizes the σ and χ phases in the Mo–Re and W–Re systems. The results evidence the preference of Re for lower coordination number site occupancy and are in very good agreement with the experimental measurements. Tentative ab initio phase diagrams have also been drawn.
81.30.Bx Phase diagrams of metals and alloys
61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling
Issue 3 (27 January 2010)
Received 28 August 2009, in final form 1 December 2009
Published 21 December 2009
J-C Crivello and J-M Joubert 2010 J. Phys.: Condens. Matter 22 035402
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