Study of phase stability in the σ-FeCr system

Cieślak, J.; Toboła, J.; Dubiel, S.

doi:10.1016/j.intermet.2012.01.023

Cited by 9 publications

(8 citation statements)

References 18 publications

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“…When mixed occupancy of sublattice sites was considered it was only to the extent as necessitated by the cluster expansion method, say when nearest neighbor interactions between sites of the same type needed to be evaluated, such as is the case in the σ structure 21–24 . Mixed occupancy was considered in the specific context of the coherent potential approximation 25 , and for several configurations in the Fe-Cr σ structure 26 but an in-depth analysis including associated effects such as due to lattice vibrations remains lacking. Here, we address this issue by considering many partially occupied configurations of a non-trivial technically important carbide phase, Cr 23 C 6 , while including vibrational effects.…”

Section: Introductionmentioning

confidence: 99%

Effect of mixed partial occupation of metal sites on the phase stability of γ-Cr23−xFe x C6 (x = 0–3) carbides

Souissi

Sluiter

Matsunaga

et al. 2018

Sci Rep

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The effect of mixed partial occupation of metal sites on the phase stability of the γ-Cr23−xFexC6 (x = 0–3) carbides is explored as function of composition and temperature. Ab initio calculations combined with statistical thermodynamics approaches reveal that the site occupation of the carbides may be incorrectly predicted when only the commonly used approach of full sublattice occupation is considered. We found that the γ-M23C6 structure can be understood as a familiar sodium chloride structure with positively charged rhombic dodecahedron (M(4a) M12(48h)) and negatively charged cubo-octahedron (M8(32f) C6(24e)) super-ion clusters, together with interstitial metal atoms at the 8c sites. The stability of the partially occupied phase can be easily rationalized on the basis of a super-ion analysis of the carbide phase. This new understanding of γ-M23C6 carbides may facilitate further development of high-chromium heat-resistant steels.

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Section: Introductionmentioning

confidence: 99%

Effect of mixed partial occupation of metal sites on the phase stability of γ-Cr23−xFe x C6 (x = 0–3) carbides

Souissi

Sluiter

Matsunaga

et al. 2018

Sci Rep

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“…Recently the site occupation in the σ-phase has been widely studied by such methods [5][6][7][8][9][10][11][12][13]. However, most of these methods were based on a formalism, which is quite computationally demanding.…”

Section: Introductionmentioning

confidence: 99%

Ab Initio Study of Lattice Site Occupancies in Binary Sigma Phases Using a Single-Site Mean Field Model

et al. 2012

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The site occupation of binary Fe-Cr, Co-Cr, Re-W and Fe-V sigma phases is studied in the present work with a first-principles-based single-site mean field theory. We show that the alloy components in these systems exhibit similar site preferences except for the Re-W system, where the occupation of two sites is reversed in agreement with previously published works. In case of the FeV sigma phase, for which the size mismatch between the alloy components is large, we also include into our consideration the effect of local lattice relaxations. The obtained results are found in good agreement with the experimental data and previous theoretical studies.

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“…This means that mechanical properties of the alloy are strongly related to precipitation of the brittle r-FeCr phase and the increase of defectsÕ density such as dislocations and deformation twins. The hard and brittle r-FeCr phase hinders dislocation motion and thus improves to the strength of Specimen B ( Ref 11,27). In addition, the stress of Specimen B increases gradually with the variation of the grain shape from equiaxed grains to long strip grains (Fig.…”

Section: Morphology Characteristic Of the Plate-shaped R-fecr Phasementioning

confidence: 97%

Precipitation Behavior of σ-FeCr Phases in Hastelloy C-2000 Superalloy Under Plastic Deformation and Aging Treatment

Yuan

Zhang

et al. 2014

J. of Materi Eng and Perform

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Precipitation behavior and structural feature of the r-FeCr phase in Hastelloy C-2000 alloy under plastic deformation and aging treatment are investigated using scanning electron microscopy, transmission electron microscope, and x-ray diffraction. The plate-shaped r-FeCr phase can precipitate in the alloy by plastic deformation and aging treatment because of the increase of both defect density and heterogeneity of alloying elements. This phase is distributed along the interface between matrix and deformation twins. The appearance of unidirectional faults on surface of the r-FeCr phase indicates that it may be a metastablephase. Because of the precipitation of the brittle r-FeCr phase and the increase of defectsÕ density such as dislocation and deformation twins in the matrix, mechanical properties of the alloy are improved remarkably.

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Study of phase stability in the σ-FeCr system

Cited by 9 publications

References 18 publications

Effect of mixed partial occupation of metal sites on the phase stability of γ-Cr23−xFe x C6 (x = 0–3) carbides

Effect of mixed partial occupation of metal sites on the phase stability of γ-Cr23−xFe x C6 (x = 0–3) carbides

Ab Initio Study of Lattice Site Occupancies in Binary Sigma Phases Using a Single-Site Mean Field Model

Precipitation Behavior of σ-FeCr Phases in Hastelloy C-2000 Superalloy Under Plastic Deformation and Aging Treatment

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