Prediction of σ Phase Formation in Fe–Cr–Ni–Mo–N Alloys

Fukumoto, Shigeo; Oikawa, Yuusuke; Tsuge, Shinji; Nomoto, Sukeharu

doi:10.2355/isijinternational.50.445

Cited by 22 publications

(10 citation statements)

References 21 publications

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“…The formation of sigma phase in stainless steel, and the influence of composition and aging, as well as the effects on mechanical and corrosion properties, has been extensively studied over the years. [4][5][6][7][8][9] A recent review of sigma phase has been written by Hsieh and Wu. 3) Studies in detail on the precipitation kinetics for longer times have been made, for example by Erneman et al, who quantified the influence of silicon for incorporation in thermodynamic databases.…”

Section: Early Precipitation Stages Of Sigma Phase In Alloy 28 Studiementioning

confidence: 99%

Early Precipitation Stages of Sigma Phase in Alloy 28 Studied with Scanning Electron Microscopy and Atom Probe Tomography

et al. 2021

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This study deals with early stages of sigma phase growth in a high end austenitic stainless steel-Alloy 28 (EN 1.4563/UNS N08028). Its precipitation kinetics was followed by a series of heat treatments at 800°C for holding times up to 30 000 s. The samples were studied with high resolution scanning electron microscopy and atom probe tomography. Detailed image analysis of the micrographs made it possible to quantify the growth rate of the precipitates. It was shown that diffusion limited growth along grain boundaries was about 15 times faster than growth perpendicular to a grain face. By combining the image data with quantitative chemical analysis of the phase boundaries, it was possible to estimate diffusion coefficients in the lattice and in the grain boundaries; grain boundary diffusion coefficients were about 250 times those of the lattice.

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Section: Early Precipitation Stages Of Sigma Phase In Alloy 28 Studiementioning

confidence: 99%

Early Precipitation Stages of Sigma Phase in Alloy 28 Studied with Scanning Electron Microscopy and Atom Probe Tomography

et al. 2021

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“…Fukumoto et al [43] studied the prediction of sigma-phase formation in Fe-Cr-Ni-Mo-N alloy using experiments and Md-PHACOMP (Phase Computation) and compared the results with a multiphase-field model based on the models by Steinbach et al as implemented in the software MICRESS.…”

Section: Introductionmentioning

confidence: 99%

Phase-Field Modeling of Sigma-Phase Precipitation in 25Cr7Ni4Mo Duplex Stainless Steel

Malik

Odqvist

Höglund

et al. 2017

Metall Mater Trans A

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Phase-field modeling is used to simulate the formation of sigma phase in a model alloy mimicking a commercial super duplex stainless steel (SDSS) alloy, in order to study precipitation and growth of sigma phase under linear continuous cooling. The so-called Warren-Boettinger-McFadden (WBM) model is used to build the basis of the multiphase and multicomponent phase-field model. The thermodynamic inconsistency at the multiple junctions associated with the multiphase formulation of the WBM model is resolved by means of a numerical Cut-off algorithm. To make realistic simulations, all the kinetic and the thermodynamic quantities are derived from the CALPHAD databases at each numerical time step, using Thermo-Calc and TQ-Interface. The credibility of the phase-field model is verified by comparing the results from the phase-field simulations with the corresponding DICTRA simulations and also with the empirical data. 2D phase-field simulations are performed for three different cooling rates in two different initial microstructures. A simple model for the nucleation of sigma phase is also implemented in the first case. Simulation results show that the precipitation of sigma phase is characterized by the accumulation of Cr and Mo at the austenite-ferrite and the ferrite-ferrite boundaries. Moreover, it is observed that a slow cooling rate promotes the growth of sigma phase, while a higher cooling rate restricts it, eventually preserving the duplex structure in the SDSS alloy. Results from the phase-field simulations are also compared quantitatively with the experiments, performed on a commercial 2507 SDSS alloy. It is found that overall, the predicted morphological features of the transformation and the composition profiles show good conformity with the empirical data.

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“…[4][5][6] As a robust method of simulation, phase field (PF) has been developed for several decades and applied successfully in the solidification field. [7][8][9][10][11][12][13] Currently, several PF models have been developed to simulate dynamic solidification of the welding process. Farzadi et al 14 had developed a PF model to simulate solidification microstructures of the weld pool at different locations along the fusion boundary during gas tungsten arc welding of Al-3 wt-% Cu alloy.…”

Section: Introductionmentioning

confidence: 99%

A phase field investigation of dendrite morphology and solute distributions under transient conditions in an Al–Cu welding molten pool

Wang¹,

Wei²,

Zhan³

et al. 2016

Science and Technology of Welding and Joining

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A quantitative phase field model is developed to simulate dendrite morphology and solute distributions of the Al-4 wt-% Cu alloy in Gas Tungsten Arc Welding (GTAW) welding molten pool under transient conditions. The functions of temperature gradient and travel velocity are used to obtain transient conditions of the welding molten pool. Time evolutions of the dendrite morphology, solute distributions of different positions and interfaces are obtained. The dendrite growth process can be divided into four stages, namely linear growth, non-linear growth, competitive growth and short-term steady growth. The solute concentration near the primary dendrite tip region is the smallest, while solute concentration is larger in the front of plane crystals growth interface and the solute concentration in the liquid region among the primary dendrites is obviously the largest, where the solute segregation forms readily. For the given welding parameters, the dendrite morphology and the initial instability of solid/liquid interface agree well with the experimental result.

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Prediction of σ Phase Formation in Fe–Cr–Ni–Mo–N Alloys

Abstract: Fig. 8. Relationship between molar fraction of phases and temperature by multiphase-field model in Fe-25.3%Cr-16.4%Ni-2.5%Mo-0.24%N alloy.

Cited by 22 publications

References 21 publications

Early Precipitation Stages of Sigma Phase in Alloy 28 Studied with Scanning Electron Microscopy and Atom Probe Tomography

Early Precipitation Stages of Sigma Phase in Alloy 28 Studied with Scanning Electron Microscopy and Atom Probe Tomography

Phase-Field Modeling of Sigma-Phase Precipitation in 25Cr7Ni4Mo Duplex Stainless Steel

A phase field investigation of dendrite morphology and solute distributions under transient conditions in an Al–Cu welding molten pool

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