Phase-field study on the formation of first-neighbour topological clusters during the isotropic grain growth

Perumal, Ramanathan; Amos, P.G. Kubendran; Selzer, Michael; Nestler, Britta

doi:10.1016/j.commatsci.2017.08.043

Cited by 22 publications

(8 citation statements)

References 62 publications

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“…Moreover, it has been shown through asymptotic analysis that the phase-eld model recovers sharp-interface solutions, despite the di use interface [24,25]. e phase-eld technique has been adopted to numerically investigate both solidi cation and solid-state transformations [26,27], including eutectoid decomposition [28,29], and curvature-driven evolutions [30,31,32,33,34]. However, except for the previous work of the present authors, not much has been reported on the non steady-state transformation using this technique.…”

Section: Introductionmentioning

confidence: 99%

The non-steady-state growth of divergent pearlite in Fe–C–Mn steels: a phase-field investigation

et al. 2020

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e eutectoid decomposition of austenite is generally analysed as a steady-state transformation. Although such a time-invariant framework is appropriate for binary systems, in ternary Fe-C-Mn alloys, particularly in the three-phase regime, a characteristic non-stationary equilibrium condition results in the formation of a unique microstructure, called 'divergent pearlite' .In the present work, the isothermal growth of the divergent pearlite, under di erent transformation temperatures; 605°C, 625°C and 650°C, is investigated by adopting a phase-eld approach which establishes local-equilibrium (LE) condition across the interface. ough most theoretical approaches intend to setup such condition, the current numerical technique elegantly recovers the non-stationary partitioning equilibrium (P-LE). e thermodynamical framework, which dictates this unique equilibrium condition, is introduced by incorporating the CALPHAD-based data. In addition to rendering the microstructure which is consistent with the observed divergentpearlite, the factors governing the characteristic kinetics and phase distributions are analysed. In complete agreement with the existing studies, it is recognised that the non steady-state growth is induced by a proportional decrease in the matrix carbon-content, which reduces the transformation kinetics, by in uencing the Mn partitioning driving-force. e characteristic proportionality which exists between these governing factors is unraveled in the current investigation. Moreover, it is also identi ed that the transition from the non steady-state evolution in three-phase regime to predominantly steady state in two-phase regime, is continuous. In other words, at 1 higher undercooling, a resolvable segment of time-invariant growth is observed in the initial stages, which is subsequently followed by the divergent evolution.

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Section: Introductionmentioning

confidence: 99%

The non-steady-state growth of divergent pearlite in Fe–C–Mn steels: a phase-field investigation

et al. 2020

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“…rough the parameter γ αβδ , the third order term in Eqn. (11) furthermore averts the formation of spurious third phases [54,60].…”

Section: Simulation Setupmentioning

confidence: 99%

Influence of stress-free transformation strain on the autocatalytic growth of bainite: A multiphase-field analysis

et al. 2020

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Analytical treatments, formulated to predict the rate of the bainite transformation, de ne autocatalysis as the growth of the subunits at the bainite-austenite interface. Furthermore, the role of the stress-free transformation strain is o en translated to a thermodynamic criterion that needs to be ful lled for the growth of the subunits. In the present work, an elastic phase-eld model, which elegantly recovers the sharp-interface relations, is employed to comprehensively explicate the e ect of the elastic energy on the evolution of the subunits. e primary nding of the current analysis is that the role of eigenstrains in the bainite transformation is apparently complicated to be directly quanti ed as the thermodynamic constraint. It is realized that the inhomogeneous stress state, induced by the growth of the primary subunit, renders a spatially dependent ill-and well-favored condition for the growth of the secondary subunits. A favorability contour, which encloses the sections that facilitate the elastically preferred growth, is postulated based on the elastic interaction. rough the numerical analyses, the enhanced growth of the subunits within the favorability-contour is veri ed. Current investigations show that the morphology and size of the elastically preferred region respectively changes and increases with the progressive growth of the subunits.

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“…Consequently, the volume of the evolving phase is not preserved, but progressively changes with the transformation. erefore, curvature-driven energy-minimising changes in a microstructure, which have been analysed through the Allen-Cahn technique, have largely been con ned to grain growth [28,29].…”

Section: Introductionmentioning

confidence: 99%

Limitations of preserving volume in Allen-Cahn framework for microstructural analysis

Amos

Schoof

Santoki

et al. 2020

Computational Materials Science

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Preserving volume in the Allen-Cahn framework is appealing as a computationally-e cient alternate for Cahn-Hilliard approach. e limitations of adopting volume-preserved Allen-Cahn treatment to analyse curvature-driven morphological transformations in chemical equilibrium is unraveled in the present work. e outcomes of redistribution-energy technique, which operates in Allen-Cahn framework, and a thermodynamically-consistent generalised quasi-Allen-Cahn (qAC) treatment, involving a conserved variable, is comparatively studied to explicate the limitations of the former. Analysis of representative microstructural evolution, in two-and threedimension, indicates that preserving volume in Allen-Cahn formalism renders an inaccurate transformation mechanism and nal phase-distribution, which signi cantly deviate from the experimental observations and theoretical predictions. Moreover, it is shown that the redistributionenergy technique, in its existing form, fails to recover the thermodynamic condition imposed on the system.

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Phase-field study on the formation of first-neighbour topological clusters during the isotropic grain growth

Cited by 22 publications

References 62 publications

The non-steady-state growth of divergent pearlite in Fe–C–Mn steels: a phase-field investigation

The non-steady-state growth of divergent pearlite in Fe–C–Mn steels: a phase-field investigation

Influence of stress-free transformation strain on the autocatalytic growth of bainite: A multiphase-field analysis

Limitations of preserving volume in Allen-Cahn framework for microstructural analysis

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