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Modeling the effect of prior austenite grain size on bainite formation kinetics

dos Santos Avila, D. (author), Offerman, S.E. (author), Santofimia, Maria Jesus (author)

While experiments show that refining the prior austenite grain size can either accelerate or decelerate bainite formation in steels, kinetic models based on the successive nucleation of bainitic ferrite subunits can only predict an acceleration. In this work we develop a physically-based model for bainite kinetics assuming a displacive growth...

journal article 2024

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Selective oxidation of aluminium in Mo(Al,Si)₂

Ding, Z. (author), Brouwer, J.C. (author), Kwakernaak, C. (author), Hermans, M.J.M. (author), Popovich, V. (author), Quadakkers, Willem J. (author), Sloof, W.G. (author)

Mo(Al_xSi_1-x)₂ alloy with x in the range of 0.35–0.65 were prepared by a one-step spark plasma sintering. To study the exclusive formation of an α-Al₂O₃ scale, oxidation experiments were conducted in low and high oxygen partial pressure ambient at 1373 K; viz.: 10⁻¹⁴ and 0.21...

journal article 2023

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In situ TEM observations of the growth of bainitic ferrite in an Fe-0.3C-3Mn-1.5Si-0.15Mo steel

Nutter, John (author), Qi, Jiahui (author), Farahani, H. (author), Rainforth, W. Mark (author), van der Zwaag, S. (author)

The current study reports in situ TEM observations of the growth of bainitic ferrite in an Fe-0.3C-3Mn-1.5Si-0.15Mo steel held isothermally at 300 °C with a higher spatio-temporal resolution than in previous studies. Significant variations were found in the lengthening rate, with the highest being in excess of 30,000 nm.s⁻¹ while...

journal article 2023

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Details of pearlite to austenite transformation in steel: Experiments and phase-field modeling

Mattos Ferreira, V. (author), Mecozzi, M.G. (author), Petrov, R.H. (author), Sietsma, J. (author)

The austenitization of an initial pearlitic microstructure is simulated using the phase field model to achieve insight into White Etching Layer (WEL) formation in pearlitic railway steels. The simulations take into account the resolution of the cementite lamellae within a pearlite colony as well as the presence of pro-eutectoid ferrite. The...

journal article 2023

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Effect of microstructure on tensile properties of quenched and partitioned martensitic stainless steels

Sierra Soraluce, A. (author), Li, G. (author), Santofimia, Maria Jesus (author), Molina-Aldareguia, J. M. (author), Smith, A. (author), Muratori, M. (author), Sabirov, I. (author)

Quenching and partitioning (Q&P) treatment has been proven effective in manufacturing advanced high strength steels with high content of retained austenite, showing the improved balance of high strength and sufficient ductility. This method has been very well elaborated for carbon steel processing over the last two decades. Though it can...

journal article 2023

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Microstructure estimation and validation of ER110S-G steel structures produced by wire and arc additive manufacturing

Mishra, V. (author), Babu, A. (author), Schreurs, R. (author), Wu, K. (author), Hermans, M.J.M. (author), Ayas, C. (author)

Wire and Arc Additive Manufacturing (WAAM) emerged as a manufacturing process for large scale structures with extensive form and design freedom. WAAM can be fully exploited once the relation between the transient thermal history and its relation to microstructure development and resultant mechanical properties is established. This relation...

journal article 2023

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Investigation of coarsening of oxide nanoparticles at 1400 K and its effect on the microstructure formation of an ODS Eurofer steel

Marques Pereira, V. (author), Davis, T. P. (author), Mayoral, M. H. (author), Kumar, A. (author), Schut, H. (author), Sietsma, J. (author)

Oxide Dispersion Strengthened (ODS) steels are potential candidate materials for application as structural components of fission and fusion reactors, known for their high thermal stability, high resistance to creep and to radiation-induced damage. These attractive properties result from the presence of the fine and highly thermally stable...

journal article 2022

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Fundamental study of nonclassical nucleation mechanisms in iron

Ou, X. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)

Nucleation is the re-arrangement of a small number of atoms in the structure of a material leading to a new phase. According to the classical nucleation theory, a nucleus will grow if there is an energetically favourable balance between the stability of the newly formed structure and the energy costs associated to the formation of strains and...

journal article 2022

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Microstructure development of pearlitic railway steels subjected to fast heating

Mattos Ferreira, V. (author), Mecozzi, M.G. (author), Petrov, R.H. (author), Sietsma, J. (author)

The influence of soaking and cooling rates on the final microstructure of a R260Mn pearlitic railway steel subjected to fast heating is investigated. Fast-heating experiments followed or not by soaking and cooling at different rates were performed using quenching dilatometry on railway steel specimens obtained from the rail head. Additional...

journal article 2022

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The Role of Parent Phase Topology in Double Young–Kurdjumow–Sachs Variant Selection during Phase Transformation in Low-Carbon Steels

Kestens, L.A.I. (author), Nguyen-Minh, Tuan (author), Petrov, R.H. (author)

The present paper investigates the role of parent phase topology on a crystallographic variant selection rule. This rule assumes that product phase nuclei appear at certain grain boundaries in the parent structure, such that a specific crystallographic orientation relationship is observed with both parent grains at either side of the grain...

journal article 2022

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Understanding ferrite deformation caused by austenite to martensite transformation in dual phase steels

Atreya, V. (author), Bos, C. (author), Santofimia, Maria Jesus (author)

During the production of DP steels, the volume expansion and shape change accompanying the austenite to martensite transformation is accommodated by the deformation of surrounding ferrite grains. The extent of the deformation in ferrite grains ultimately affects the mechanical properties of DP steels. Using electron backscatter diffraction...

journal article 2021

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Effect of L-alanyl-glycine dipeptide on calcium oxalate crystallization in artificial urine

Polat, S. (author), Eral, H.B. (author)

Pathological crystallization of calcium oxalate (CaOx), the most common constituent of kidney stones, has attracted much attention due to recent surge in reported natural and synthetic additives effectively inhibiting its nucleation and growth. The aim of this study is to investigate the effect of L-alanyl–glycine (Ala–Gly), a dipeptide...

journal article 2021

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A novel 3D mixed-mode multigrain model with efficient implementation of solute drag applied to austenite-ferrite phase transformations in Fe-C-Mn alloys

Fang, H. (author), van der Zwaag, S. (author), van Dijk, N.H. (author)

A computational 3D model that accounts for both nucleation and interface migration is a very useful tool to monitor and grasp the complexity of microstructure formation in low-alloyed steels. In the present study we have developed a 3D mixed-mode multigrain model for the austenite-ferrite and the austenite-ferrite-austenite formation capable...

journal article 2021

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Phase-transformation and precipitation kinetics in vanadium micro-alloyed steels by in-situ, simultaneous neutron diffraction and SANS

Ioannidou, C. (author), Navarro Lopez, A. (author), Dalgliesh, Robert M. (author), Rijkenberg, Arjan (author), Geerlofs, N. (author), Pappas, C. (author), Sietsma, J. (author), van Well, A.A. (author), Offerman, S.E. (author)

In-situ Neutron Diffraction and Small-Angle Neutron Scattering (SANS) are employed for the first time simultaneously in order to reveal the interaction between the austenite to ferrite phase transformation and the precipitation kinetics during isothermal annealing at 650 and at 700 °C in three steels with different vanadium (V) and carbon (C)...

journal article 2021

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Coalescence of martensite under uniaxial tension of iron crystallites by atomistic simulations

Ou, X. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)

Molecular dynamics simulations are used to study the effects of tensile loading on nucleation and subsequent growth of bcc phase in pure fcc iron. The results show that orientation variant selection occurs during the stress-induced fcc-to-bcc transformation, which leads to the coalescence of neighbouring bcc platelets with identical...

journal article 2020

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In situ high-temperature EBSD and 3D phase field studies of the austenite-ferrite transformation in a medium Mn steel

Farahani, H. (author), Zijlstra, Gerrit (author), Mecozzi, M.G. (author), Ocelík, Václav (author), De Hosson, Jeff Th M. (author), van der Zwaag, S. (author)

In this research, in situ high-temperature electron backscattered diffraction (EBSD) mapping is applied to record and analyze the migration of the α/3 interfaces during cyclic austenite-ferrite phase transformations in a medium manganese steel. The experimental study is supplemented with related 3D phase field (PF) simulations to better...

journal article 2019

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Prediction of density and volume variation of hematite ore particles during in-flight melting and reduction

Chen, Z. (author), Qu, Ying xia (author), Zeilstra, Christiaan (author), Van Der Stel, Jan (author), Sietsma, J. (author), Yang, Y. (author)

HIsarna is a promising ironmaking technology to reduce CO ₂ emission. Information of phase transformation is essential for reaction analysis of the cyclone reactor of the HIsarna process. In addition, data of density and volume of the ore particles are necessary for estimation of the residence time of the particles in the cyclone...

journal article 2019

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Direct TEM observation of α/γ interface migration during cyclic partial phase transformations at intercritical temperatures in an Fe-0.1C −0.5Mn alloy

Nutter, J. (author), Farahani, H. (author), Rainforth, W. M. (author), van der Zwaag, S. (author)

The kinetic behaviour of austenite/ferrite interfaces in a low carbon – 0.5 mass% Mn containing steel during Cyclic Partial Phase Transformation (CPPT) experiments has been investigated using hot stage Transmission Electron Microscopy (TEM). Individual interfaces were observed to display behaviour typical of CPPT experiments as recorded in...

journal article 2019

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Interaction of precipitation with austenite-to-ferrite phase transformation in vanadium micro-alloyed steels

Ioannidou, C. (author), Arechabaleta Guenechea, Z. (author), Navarro Lopez, A. (author), Rijkenberg, Arjan (author), Dalgliesh, Robert M. (author), Kölling, S. (author), Bliznuk, Vitaliy (author), Pappas, C. (author), Sietsma, J. (author), van Well, A.A. (author), Offerman, S.E. (author)

The precipitation kinetics of vanadium carbides and its interaction with the austenite-to-ferrite phase transformation is studied in two micro-alloyed steels that differ in vanadium and carbon concentrations by a factor of two, but have the same vanadium-to-carbon atomic ratio of 1:1. Dilatometry is used for heat-treating the specimens and...

journal article 2019

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Modelling study on the three-dimensional neutron depolarisation response of the evolving ferrite particle size distribution during the austenite–ferrite phase transformation in steels

Fang, H. (author), van der Zwaag, S. (author), van Dijk, N.H. (author)

The magnetic configuration of a ferromagnetic system with mono-disperse and poly-disperse distribution of magnetic particles with inter-particle interactions has been computed. The analysis is general in nature and applies to all systems containing magnetically interacting particles in a non-magnetic matrix, but has been applied to steel...

journal article 2018