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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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Atreya, V. (author)Dual-phase (DP) steels are an important class of advanced high-strength steels (AHSS) and constitute a major share of steels for the automotive industry. A microstructure consisting of hard martensite embedded in a soft ferritic matrix gives them a good combination of strength and ductility. The martensite formation in the microstructure from...doctoral thesis 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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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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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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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<sub>x</sub>Si<sub>1-x</sub>)<sub>2</sub> 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-Al<sub>2</sub>O<sub>3</sub> scale, oxidation experiments were conducted in low and high oxygen partial pressure ambient at 1373 K; viz.: 10<sup>−14</sup> and 0.21...journal article 2023
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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<sup>−1</sup> while...journal article 2023
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Marques Pereira, V. (author)An approach to improve the performance of steels for fusion and fission reactors is to reinforce them with oxide nanoparticles. These can hinder dislocation and grain boundary movement and trap radiation-induced defects, thus increasing creep and radiation damage resistance. Steels containing these oxide particles are called ODS steels (Oxide...doctoral thesis 2022
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Ioannidou, C. (author)The focus of the present work is on the micro-alloying element vanadium, which is well known for providing precipitation strengthening to steels and which has, therefore, attracted a lot of interest the last decades. Vanadium carbide precipitation can take place in the migrating austenite/ferrite interface during the austenite-to-ferrite phase...doctoral thesis 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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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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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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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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Zhu, WEIJIA (author)Nitinol shape memory alloys (SMAs) have a unique combination of shape memory capability, making it an attractive material for various engineering and biomedical applications. Additive manufacturing (AM) by laser powder bed fusion (L-PBF) allows to produce Nitinol net shape parts, which broadens its applications. Due to the high heating and...master thesis 2021
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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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Dai, Zongbiao (author), Chen, Hao (author), Ding, Ran (author), Lu, Qi (author), Zhang, Chi (author), Yang, Zhigang (author), van der Zwaag, S. (author)Over many decades, significant efforts have been made to improve the strength-elongation product of advanced high strength steels (AHSSs) by creating tailored multi-phase microstructures. Successive solid-state phase transformations for steels with a well selected chemical composition turned out to be the key instrument in the realisation of...review 2021
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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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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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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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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