Intermediate phases of the α-σ phase transition in the Fe-Cr system

Zinc diffusion-induced degradation of AISI 316LN austenitic stainless steel pot equipment used in 55%Al-Zn and Zn-Al-Mg coating metal baths is described. SEM/EDS analyses results showed that the diffused zinc reacts with nickel from the austenite matrix and results in the formation of Ni-Zn intermetallic compounds. The Ni-Zn intermetallic phase and the nickel depleted zones form a periodic and alternating layered structure and a mechanism for its formation is proposed. The role of cavities and interconnected porosity in zinc vapour diffusion-induced degradation and formation of Ni-Zn intermediate phases is also discussed. The formation of Ni-Zn intermediate phases and the depletion of nickel in the austenite matrix results in the precipitation of σ-phase and α-ferrite in the nickel depleted regions of the matrix. This reaction will lead to increased susceptibility to intergranular cracking and accelerated corrosion of immersed pot equipment in the coating bath. Zinc diffusion induced precipitation of σ-phase in austenitic stainless steels that we are reporting in this work is a new insight with important implications for the performance of austenitic stainless steels in zinc containing metal coating baths and other process industries. This new insight will further lead to improved understanding of the role of substitutional diffusion and the redistribution of alloying elements in the precipitation of σ-phase in austenitic stainless steels.

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First 119Sn Mössbauer-effect study of the σ-phase in the Fe-Cr system

Journal of Magnetism and Magnetic Materials ◽

10.1016/0304-8853(92)90073-w ◽

1992 ◽

Vol 115 (2-3) ◽

pp. 307-310 ◽

Cited By ~ 1

Author(s):

S.M. Dubiel ◽

B.F.O. Costa ◽

N. Ayres de Campos

Keyword(s):

Mössbauer Effect ◽

Effect Study ◽

Mossbauer Effect ◽

Σ Phase ◽

Cr System

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Revised thermodynamic description of the Fe-Cr system based on an improved sublattice model of the σ phase

Calphad ◽

10.1016/j.calphad.2017.10.002 ◽

2018 ◽

Vol 60 ◽

pp. 16-28 ◽

Cited By ~ 18

Author(s):

Aurélie Jacob ◽

Erwin Povoden-Karadeniz ◽

Ernst Kozeschnik

Keyword(s):

Thermodynamic Description ◽

Sublattice Model ◽

Σ Phase ◽

Cr System

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Phase transition sequences in tetramethylammonium tetrachlorometallates by X-ray diffraction and spectroscopic measurements

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

10.1107/s2052520617006412 ◽

2017 ◽

Vol 73 (5) ◽

pp. 844-855 ◽

Cited By ~ 5

Author(s):

Jack Binns ◽

Garry J McIntyre ◽

José A. Barreda-Argüeso ◽

Jesús González ◽

Fernando Aguado ◽

...

Keyword(s):

Phase Transition ◽

Point Group ◽

Lone Pair ◽

Group Symmetry ◽

First Principles Calculations ◽

X Ray Diffraction ◽

Intermediate Phases ◽

Increasing Temperature ◽

First Time ◽

Prototype Phase

The phase transition sequences of two members of the tetramethylammonium tetrachlorometallate(III) family of hybrid organic–inorganic salts have been determined and structurally characterized as a function of temperature for the first time. Unusually, a reduction in point-group symmetry with increasing temperature until reaching a cubic prototype phase is observed. Two additional intermediate phases are observed for Fe3+. First-principles calculations and the presence of short Cl...Cl contacts for Ga3+suggest the [GaCl4]−anion to be conformationally hindered due to stronger lone-pair–σ-hole interactions. The conformationally more flexible Fe3+structures show sublattice melting with the onset of rotational disorder in the [NMe4]+cations occurring 40 K below the corresponding onset of rotational disorder in the [FeCl4]−sublattice.

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HALL EFFECTS AND SUPERCONDUCTIVITY OF ANORPHOUS InSb AND ITS METASTABLE INTERMEDIATE PHASES IN THE PROCESS OF THE CRYSTALLIZATION PHASE TRANSITION

Acta Physica Sinica ◽

10.7498/aps.36.1041 ◽

1987 ◽

Vol 36 (8) ◽

pp. 1041

Author(s):

Cao Xiao-wen，Zhao Dian-sheng，Zhang Yu-heng

Keyword(s):

Phase Transition ◽

Intermediate Phases ◽

Hall Effects

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Phase transition ‘ordering-phase separation’ in alloys of Ni–Cr system

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2015.05.027 ◽

2015 ◽

Vol 165 ◽

pp. 14-18 ◽

Cited By ~ 8

Author(s):

Y. Ustinovshikov

Keyword(s):

Phase Transition ◽

Phase Separation ◽

Cr System

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Metastable copper-chromium alloy films

Journal of Materials Research ◽

10.1557/jmr.1992.1370 ◽

1992 ◽

Vol 7 (6) ◽

pp. 1370-1376 ◽

Cited By ~ 21

Author(s):

A.P. Payne ◽

B.M. Clemens

Keyword(s):

Phase Transition ◽

Grazing Incidence ◽

Phase Region ◽

Heat Of Mixing ◽

Chromium Alloy ◽

Two Phase ◽

Bcc Lattice ◽

Bcc Structure ◽

Nonequilibrium States ◽

Cr System

Due to the large positive heat of mixing associated with the Cu–Cr binary system, solid solutions exist only as nonequilibrium states. In this study, a series of metastable Cu–Cr alloys ranging in composition from 14.1 to 75.4% copper was fabricated by sputter deposition. Symmetric, asymmetric, and grazing incidence x-ray diffraction geometries were used to trace the phase transition from bcc to fcc crystal structures with increasing Cu fraction. It is shown that the transition takes place not by a two-phase region suggested by equilibrium thermodynamics, but rather through gradual disordering of the bcc lattice as copper atoms are substitutionally accommodated. At a critical saturation near 71% Cu, the bcc structure becomes unstable relative to the fcc and a phase transition occurs. The free energies of the kinetically constrained Cu–Cr system are modeled and the results are found to agree well with observed behavior.

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