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Venkatesan, P. (author), Vander Hoogerstraete, Tom (author), Hennebel, Tom (author), Binnemans, Koen (author), Sietsma, J. (author), Yang, Y. (author)NdFeB magnet waste is one of the important secondary resources from which rare-earth elements (REEs) can be recovered. Herein we present an electrochemical route to selectively extract REEs from the magnet waste at room temperature. First, the magnet waste was partially leached with HCl. The partial leachate along with undissolved magnet...journal article 2018
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Arechabaleta Guenechea, Z. (author), van Liempt, P. (author), Sietsma, J. (author)Understanding the intricate structure of dislocations in metals is a major issue in materials science. In this paper we present a comprehensive approach for the characterisation of dislocation networks, resulting in accurate quantification and significantly increasing the insight into the dislocation structure. Dislocation networks in metals...journal article 2018
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Nishikawa, A.S. (author), Santofimia, Maria Jesus (author), Sietsma, J. (author), Goldenstein, Hélio (author)In the present study the microstructural evolution and kinetics of carbon redistribution during the partitioning step of the Quenching and Partitioning process are investigated by means of a modeling approach that simultaneously considers the martensite-austenite carbon partitioning and the decomposition of austenite into bainitic ferrite....journal article 2018
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Karewar, S.V. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)Molecular dynamics (MD) simulations are used to study the effect of different defect configurations and their arrangements in the parent fcc phase on atomistic mechanisms during the martensitic transformation mechanisms in pure Fe. The defect configurations considered are stacking faults (SF) and twin boundaries (TB) in single crystal fcc. Three...journal article 2018
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Alizadeh Otorabad, H. (author), Tehrani, Parisa Hosseini (author), Younesian, Davood (author), Sietsma, J. (author), Petrov, R.H. (author)Studying the temperature evolution of the thermally affected zone (TAZ) of sliding surfaces is crucial because of its influence on microstructural evolution, wear, and fatigue. Due to the complexity of thermal analysis of sliding bodies, relationships that predict their surface temperature evolution are very helpful because they can be used as...journal article 2018
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Wu, J. (author), Petrov, R.H. (author), Kölling, S. (author), Godet, Stephane (author), Sietsma, J. (author)Micro- to nano-scale characterization of the microstructures in the white etching layer (WEL), observed in a Dutch R260 Mn grade rail steel, was performed via various techniques. Retained austenite in the WEL was identified via electron backscatter diffraction (EBSD), automatic crystallographic orientation mapping in transmission electron...journal article 2018
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Peelman, S. (author), Sietsma, J. (author), Yang, Y. (author)Neodymium is a critical element used in many high-tech applications. However, despite this, the EU is entirely dependent on China for its Nd supply. This has driven the EU to develop recycling strategies to recover its Nd from end-of-life (EoL) products and wastes, and establish a domestic supply. This paper proposes a process to recycle Nd from...journal article 2018
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Peelman, S. (author), Kooijman, D. (author), Sietsma, J. (author), Yang, Y. (author)The present study proposes three distinct processes to recycle rare earth elements (REE) from two low-grade secondary resources: REE-containing mine tailings and ferrous scrap from shredded waste of electrical and electronic equipment (WEEE). The first developed process extracts both REE and phosphorus from the apatite mineral contained within...journal article 2018
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Puype, A. (author), Malerba, L. (author), De Wispelaere, N. (author), Petrov, R.H. (author), Sietsma, J. (author)The microstructure of a 9Cr-1W-0.22V-0.09Ta-0.11C reduced activation ferritic/martensitic (RAFM) steel has been investigated after thermo-mechanical rolling with subsequent annealing for 30 min at temperatures of 880 °C, 920 °C, 980 °C and 1050 °C, followed by water quenching. Scanning and transmission electron microscopy investigations and...journal article 2017
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Ravi, A.M. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)Over the years, a quantitative theory to explain bainite formation kinetics has been proposed based on the nucleation kinetics of bainitic sub-units. Although the theory shows acceptable correlation with experimental results, it is observed that the kinetic models show a certain degree of discrepancy with actual kinetics. It is identified...journal article 2017
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Kim Lee, B.N. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)Understanding carbon redistribution in steels is crucial in developing advanced high strength steels. For instance, Quenching & Partitioning (Q&P) processes rely on the partitioning of carbon from martensite into austenite, where at the end of the heat treatment the carbon-enriched austenite shows higher stability at room temperature....journal article 2017
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Abbasalizadeh, A. (author), Malfliet, Annelies (author), Seetharaman, Seshadri (author), Sietsma, J. (author), Yang, Y. (author)In the present research on rare earth extraction from rare earth oxides (REOs), conversion of rare earth oxides into rare earth fluorides with fluoride fluxes is investigated in order to overcome the problem of low solubility of the rare earth oxides in molten fluoride salts as well as the formation of oxyfluorides in the fluorination process....journal article 2017
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Naeimi, M. (author), Li, Z. (author), Petrov, R.H. (author), Sietsma, J. (author), Dollevoet, R.P.B.J. (author)A new downscale test rig is developed for investigating the contact between the wheel and rail under impact-like loading conditions. This paper presents the development process of the setup, including review and synthesis of the potential experimental techniques, followed by scalability, mechanical and operational analysis of the new setup. The...journal article 2017
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Navarro Lopez, A. (author), Hidalgo Garcia, J. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)Advanced Multiphase High Strength Steels are generally obtained by applying isothermal treatments around the martensite start temperature (M<sub>s</sub>). Previous investigations have shown that bainitic ferrite can form from austenite in isothermal treatments below M<sub>s</sub>, where its formation kinetics is accelerated by the presence of...journal article 2017
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Goulas, C. (author), Mecozzi, M.G. (author), Sietsma, J. (author)In this paper, the effect of chemical inhomogeneity on the isothermal bainite formation is investigated in medium-carbon low-silicon spring steel by dilatometry and microscopy. The analysis of the microstructure at different times during transformation shows that chemical segregation of substitutional alloying elements resulting from casting...journal article 2016
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Bojack, A. (author), Zhao, L. (author), Morris, P.F. (author), Sietsma, J. (author)The influence of austenitization treatment of a 13Cr6Ni2Mo supermartensitic stainless steel (X2CrNiMoV13-5-2) on austenite formation during reheating and on the fraction of austenite retained after tempering treatment is measured and analyzed. The results show the formation of austenite in two stages. This is probably due to inhomogeneous...journal article 2016
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Ravi, A.M. (author), Sietsma, J. (author), Santofimia, M.J. (author)Bainite formation in steels begins with nucleation of bainitic ferrite at austenite grain boundaries (?/? interfaces). This leads to creation of bainitic ferrite/austenite interfaces (?/? interfaces). Bainite formation continues through autocatalysis with nucleation of bainitic ferrite at these newly created ?/? interfaces. The displacive theory...journal article 2016
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van der Stok-Nienhuis, J. (author), Robbiola, Luc (author), Giuliani, Roberta (author), Joosten, Ineke (author), Huisman, Hans (author), van Os, Bertil (author), Sietsma, J. (author)Curly malachite (CM) is found as a green cupric carbonate hydroxide corrosion product on archaeological bronze, mostly on artefacts retrieved from graves. In this paper, a morphological characterization approach is proposed, enabling the investigation of the formation process of CM. It is suggested that curly malachite precipitates from an...journal article 2016
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Wu, J. (author), Petrov, R.H. (author), Naeimi, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author), Sietsma, J. (author)White etching layer (WEL) is a frequently observed microstructural phenomenon in rail surface, formed during dynamic wheel/rail contact. It is considered as one of the main initiators for rolling contact fatigue cracks. There are several hypotheses for the formation mechanism of WEL. However, due to the complicated wheel/rail contact...journal article 2016
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Arechabaleta Guenechea, Z. (author), van Liempt, P. (author), Sietsma, J. (author)The pre-yield deformation behaviour (i.e., at stresses below the yield stress) of two materials, pure iron and a low-alloy steel, and its anelastic nature are analysed at room temperature, before and after the dislocation structures are varied by plastic deformation. It is shown, based on tensile experiments, that this behaviour can be explained...journal article 2016