Solute Segregation During Ferrite Growth: Solute/Interphase and Substitutional/Interstitial Interactions

Landeghem, H.P. Van; Langelier, Brian; Panahi, Damon; Purdy, G.R.; Hutchinson, Christopher; Botton, Gianluigi A.; Zurob, Hatem S.

doi:10.1007/s11837-016-1852-y

Cited by 24 publications

(11 citation statements)

References 15 publications

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“…In addition to ignoring carbide formation [3], or in general the interaction between different alloying elements [24,28,29], the assumed mean-field approximation of the carbon profile in austenite can limit the accuracy of the model predictions of the onset of transformation stasis [30]. Furthermore, the assumed perfect NPLE thermodynamic condition for calculation of the drag of substitutional elements during the whole transformation, may not be applicable under all conditions during the bainite formation.…”

Section: Discussionmentioning

confidence: 99%

Predicting the cooperative effect of Mn–Si and Mn–Mo on the incomplete bainite formation in quaternary Fe–C alloys

Farahani

Zwaag

2018

Philosophical Magazine Letters

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Predicting the effect of alloying elements on the degree of incomplete austenite to bainite transformation in low carbon steels is of great industrial importance. This study introduces an extended Gibbs energy balance model which makes use of an additive approach to calculate the coupled effect of Mn, Si and Mo on the fraction of bainitic ferrite after the incomplete transformation in multicomponent steels. The model predicts significant effects of Mn and Mo and the negligible effect of Si levels on the fraction of bainitic ferrite. This is attributed to the high value of dissipation of Gibbs energy caused by interfacial diffusion of Mn and Mo and low values caused by Si diffusion. The model predictions for quaternary Fe-C-Mn-Si system are comparable with the experimentally measured values of bainite fraction. For the Fe-C-Mn-Mo system, the agreement is less accurate and the accuracy decreases with increasing Mo content, which is attributed a substantial carbide formation but interaction effects between Mn and Mo or a temperature dependent binding energy cannot be ruled out. ARTICLE HISTORY

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Section: Discussionmentioning

confidence: 99%

Predicting the cooperative effect of Mn–Si and Mn–Mo on the incomplete bainite formation in quaternary Fe–C alloys

Farahani

Zwaag

2018

Philosophical Magazine Letters

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“…Modeling the growth of ferrite in low alloyed steels has been extensively investigated because of its great importance for the design of new steel grades (Guo & Enomoto, 2007). Precise measurements of the local composition of solutes at and in the vicinity of the moving interface are sparse (Fletcher et al, 2001; Thuillier et al, 2006; Danoix et al, 2016; Van Landeghem et al, 2016, 2017). Here, we explore how the measured width of the profile is dependent on the local fluctuations of the depth resolution of the technique and that, by selecting the appropriate region, the width of the profile can be in the range of 4–5 atomic (011) planes (<1 nm).…”

Section: Compositional Width Of An Interfacementioning

confidence: 99%

Reflections on the Analysis of Interfaces and Grain Boundaries by Atom Probe Tomography

et al. 2020

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Interfaces play critical roles in materials and are usually both structurally and compositionally complex microstructural features. The precise characterization of their nature in three-dimensions at the atomic scale is one of the grand challenges for microscopy and microanalysis, as this information is crucial to establish structure–property relationships. Atom probe tomography is well suited to analyzing the chemistry of interfaces at the nanoscale. However, optimizing such microanalysis of interfaces requires great care in the implementation across all aspects of the technique from specimen preparation to data analysis and ultimately the interpretation of this information. This article provides critical perspectives on key aspects pertaining to spatial resolution limits and the issues with the compositional analysis that can limit the quantification of interface measurements. Here, we use the example of grain boundaries in steels; however, the results are applicable for the characterization of grain boundaries and transformation interfaces in a very wide range of industrially relevant engineering materials.

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“…Such molecular ions may also postionize and dissociate, arriving as multiple ion hits to the detector. However, if these ions are of the same isotope (e.g., 14 N) and arrive very close to each other on the detector, one ion may be lost to the pile-up effect (Thuvander et al, 2011; Miyamoto et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

Interface Segregation and Nitrogen Measurement in Fe–Mn–N Steel by Atom Probe Tomography

et al. 2017

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Improved understanding of the interactions between solutes and the austenite/ferrite interface can benefit modeling of ferrite growth during austenite decomposition, as the transformation kinetic is significantly affected by solutes that influence interface mobility. Solute-interface interactions dominate solute segregation at the interface in binary systems, but in multi-component alloys, solute-solute interactions may also affect segregation. In this study, interface segregation in Fe-Mn-N is examined and compared with Fe-Mn-C, to reveal the extent to which C affects the segregation of Mn. Atom probe tomography (APT) is well-suited to analyze solute concentrations across the interface, as this technique combines high spatial resolution and compositional sensitivity. Measurements of Mn show that segregation is only observed for Fe-Mn-C. This demonstrates that Mn segregation is primarily driven by an affinity for C, which also segregates to the interface. However, the measurement of N in steels by APT may be affected by a variety of experimental factors. Therefore, in verifying the Fe-Mn-N result, systematic examination is conducted on the influence of pulsing method (voltage versus laser), sample preparation (ion milling versus electropolishing), and vacuum storage on the measured N concentration. Both laser pulsing and focused ion beam sample preparation are observed to decrease the apparent N concentration.

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Solute Segregation During Ferrite Growth: Solute/Interphase and Substitutional/Interstitial Interactions

Cited by 24 publications

References 15 publications

Predicting the cooperative effect of Mn–Si and Mn–Mo on the incomplete bainite formation in quaternary Fe–C alloys

Predicting the cooperative effect of Mn–Si and Mn–Mo on the incomplete bainite formation in quaternary Fe–C alloys

Reflections on the Analysis of Interfaces and Grain Boundaries by Atom Probe Tomography

Interface Segregation and Nitrogen Measurement in Fe–Mn–N Steel by Atom Probe Tomography

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