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Krugla, M. (author), Offerman, S.E. (author), Sietsma, J. (author), Hanlon, Dave N. (author)The production reality of sheet steels from casting to the end product is such that in the cases of ultra- and advanced high-strength steels, we have to deal with the segregation of elements on macro- and microlevels. Both can have a significant impact on the microstructure formation and resulting properties. There are several production stages...journal article 2024
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Kar, S. (author), Yilmaz, A. (author), Traka, K. (author), Sietsma, J. (author), Gonzalez Garcia, Y. (author)This work investigates the role of grain size and recrystallization texture in the corrosion behavior of pure iron in 0.1 M sulfuric acid solution. Annealing heat treatment was applied to obtain samples with different average grain sizes (26, 53 and 87 µm). Optical microscopy, X-ray diffraction and electron backscatter diffraction techniques...journal article 2023
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Morete Barbosa Bertolo, V. (author), Jiang, Q. (author), Terol Sanchez, M. (author), Riemslag, A.C. (author), Walters, C.L. (author), Sietsma, J. (author), Popovich, V. (author)High strength steels are widely used for structural applications, where a combination of excellent strength and ductile-to-brittle transition (DBT) properties are required. However, such a combination of high strength and toughness can be deteriorated in the heat affected zone (HAZ) after welding. This work aims to develop a relationship...journal article 2023
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Abraham Mathews, J. (author), Farahani, H. (author), Sietsma, J. (author), Petrov, R.H. (author), Mecozzi, M.G. (author), Santofimia, Maria Jesus (author)The influence of carbon concentration variations on pearlite formation (20 h at 600 °C) in a case-carburized steel is investigated. The resultant microstructure shows three distinct regions: carburized case, a transition region, and the original core. The microstructural transition from the case to the core regions is observed to be...journal article 2023
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van Dokkum, J.S. (author), Bos, Cornelis (author), Offerman, S.E. (author), Sietsma, J. (author)Modelling dislocation glide over the initial part of a stress–strain curve of metals received little attention up to now. However, dislocation glide is essential to ones understanding of the fundamental relationship between inelastic deformation and the evolution of the dislocation network structure. Therefore, we present a model of...journal article 2023
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Jiang, Quanxin (author), Morete Barbosa Bertolo, V. (author), Pallaspuro, Sakari (author), Popovich, V. (author), Sietsma, J. (author), Walters, C.L. (author)Multi-barrier cleavage models consider cleavage fracture which is characterized by a series of microscale events. One of the challenges for multi-barrier cleavage models is the strong variations of cleavage parameters across different types of steels. The source and magnitude of the variations have not been studied systematically. In the...journal article 2023
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Jiang, Quanxin (author), Morete Barbosa Bertolo, V. (author), Popovich, V. (author), Sietsma, J. (author), Walters, C.L. (author)Study of the cleavage behavior of heat treated S690 steel by a microstructure-based approach combined with finite element analysis is present in this paper. Cleavage simulations of steels subjected to heat treatments that cause grain refinement or simulate heat affected zones are performed, and are compared with experiments. It is found that...journal article 2023
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Garcia Chao, P. (author), Eipe, Jonathan J. (author), Krugla, M. (author), Bos, Cornelis (author), Sietsma, J. (author), Kranendonk, Winfried (author), Offerman, S.E. (author)In the present study, the nucleation of static recrystallization (SRX) in austenite after hot deformation is experimentally analyzed using a Ni-30 pct Fe model alloy. In agreement with the predictions by current models, nucleation rate exhibits a strong peak, early during SRX. Whereas such an early peak is explained by current models by the...journal article 2023
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Abraham Mathews, J. (author), Sietsma, J. (author), Petrov, R.H. (author), Santofimia, Maria Jesus (author)In many commercial steel processing routes, steel microstructures are reverted to an austenitic condition prior to the final processing steps. Understanding the microstructure development during austenitization is crucial for improving the performance and reliability of the microstructure that forms from austenite. In this work, austenite...journal article 2023
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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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Yilmaz, A. (author), He, X. (author), Pletincx, Sven (author), Hauffman, Tom (author), Sietsma, J. (author), Gonzalez Garcia, Y. (author)The role of prior austenite grain size (PAGS) on the passive layer properties of martensitic steels is studied. Electron backscatter diffraction analysis shows that PAGS between 5 and 66 µm were obtained after applying different heat treatments. The barrier properties of passive film deteriorate with grain refinement up to 28 µm, attributed to...journal article 2022
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Marques Pereira, V. (author), Wang, S. (author), Morgan, T. (author), Schut, H. (author), Sietsma, J. (author)In the present work, an ODS 12 Cr steel was characterized using Electron Microscopy techniques, in an as-received condition and after annealing treatments between 773 K and 1573 K. Results show a complex microstructure, with the presence of fine Y–Ti–O nanoparticles dispersed in the matrix. After annealing at 1573 K, the average diameter of Y...journal article 2022
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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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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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Sedighiani, K. (author), Traka, K. (author), Roters, Franz (author), Raabe, Dierk (author), Sietsma, J. (author), Diehl, Martin (author)Physics-based crystal plasticity models rely on certain statistical assumptions about the collective behavior of dislocation populations on one slip system and their interactions with the dislocations on the other slip systems. One main advantage of using such physics-based constitutive dislocation models in crystal plasticity kinematic...journal article 2022
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Hajizad, O. (author), Kumar, A. (author), Petrov, R.H. (author), Sietsma, J. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)Microscopic stress and strain partitioning control the mechanical and damage behavior of multiphase steels. Using a combined numerical and experimental approach, local strain distributions and deformation localization are characterized in a carbide free bainitic steel produced by continuous cooling. The microstructure of the steel consists of...journal article 2022
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Morete Barbosa Bertolo, V. (author), Jiang, Quanxin (author), Scholl, Sebastian (author), Petrov, R.H. (author), Hangen, Ude (author), Walters, C.L. (author), Sietsma, J. (author), Popovich, V. (author)The through-thickness heterogeneous microstructure of thick-section high strength steels is responsible for the significant scatter of properties along the thickness. In this study, in order to identify the critical microstructural features in the fracture behaviour and allow for design optimisation and prediction of structural failure, the...journal article 2022
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Jiang, Quanxin (author), Morete Barbosa Bertolo, V. (author), Popovich, V. (author), Sietsma, J. (author), Walters, C.L. (author)Thick section S690 QT steel is modelled with a modified multibarrier model that is based on the weakest-link mechanism. Segregation bands are modelled as discrete layers which have different grain size, yield properties, and local fracture parameters from outside of the bands. The results show that embrittlement from segregation bands can...journal article 2022
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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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Morete Barbosa Bertolo, V. (author), Jiang, Quanxin (author), Tiringer, U. (author), Walters, C.L. (author), Sietsma, J. (author), Popovich, V. (author)For structural assessment and optimal design of thick-section high-strength steels in applications under harsh service conditions, it is essential to understand the cleavage fracture micromechanisms. In this study, we assess the effects of through-thickness microstructure of an 80-mm-thick quenched and tempered S690 high-strength steel, notch...journal article 2022