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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 Bohemen, S.M.C. (author), Sietsma, J. (author)The progress of martensite formation in plain carbon steels Fe-0.46C, Fe-0.66C, and Fe-0.80C has been investigated by dilatometry. It is demonstrated that carbon enrichment of the remaining austenite due to intercritical annealing of Fe-0.46C and Fe-0.66C does not only depress the start temperature for martensite, but also slows the progress of...journal article 2009
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Van Tol, R.T. (author), Zhao, L. (author), Schut, H. (author), Sietsma, J. (author)The effect of strain on the deformation mechanisms in an austenitic Mn-based twinning induced plasticity (TWIP) steel is investigated using magnetic measurements, XRD, positron beam Doppler spectroscopy, and finite element method simulations. The experimental observations reveal the formation of a0-martensite at specific degrees of deformation,...journal article 2012
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Carvalho, I. (author), Schut, H. (author), Fedorov, A. (author), Luzginova, N. (author), Desgardin, P. (author), Sietsma, J. (author)Reduced Activation Ferritic/Martensitic steels are being extensively studied because of their foreseen application in fusion and Generation IV fission reactors. To mimic neutron irradiation conditions, Eurofer97 samples were implanted with helium ions at energies of 500 keV and 2 MeV and doses of 5x1015-1016 He /cm2, creating atomic...journal article 2013
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Santofimia, M.J. (author), Zhao, L. (author), Sietsma, J. (author)The application of the quenching and partitioning (Q&P) process in steels involves a microstructural evolution that is more complex than just the formation of martensite followed by carbon partitioning from martensite to austenite. Examples of this complexity are the formation of epitaxial ferrite during the first quenching step and the...journal article 2011
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Bahrami, A. (author), Miroux, A. (author), Sietsma, J. (author)In the present study, an age-hardening model for Al-Mg-Si alloys was developed considering cylindrical morphology with constant aspect ratio for precipitates. It is assumed that the precipitate distribution during underaging is controlled by simultaneous nucleation and growth, and after peak age, the process becomes coarsening controlled. The...journal article 2012
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Tirumalasetty, G.K. (author), Van Huis, M.A. (author), Fang, C.M. (author), Xu, Q. (author), Tichelaar, F.D. (author), Hanlon, D.N. (author), Sietsma, J. (author), Zandbergen, H.W. (author)Multiphase steels utilising composite strengthening may be further strengthened via grain refinement or precipitation by the addition of microalloying elements. In this study a Nb microalloyed steel comprising martensite, bainite and retained austenite has been studied. By means of transmission electron microscopy (TEM), we have investigated the...journal article 2011
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Luzginova, N.V. (author), Zhao, L. (author), Sietsma, J. (author)The cementite spheroidization process is investigated in hypereutectoid steels with different chromium (Cr) contents. A spheroidized structure in high-carbon steel is usually obtained by a divorced eutectoid transformation (DET) reaction, which occurs during slow cooling of austenite with fine cementite particles. A bimodal distribution of...journal article 2008
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Savran, V.I. (author), Van Leeuwen, Y. (author), Hanlon, D.N. (author), Kwakernaak, C. (author), Sloof, W.G. (author), Sietsma, J. (author)The microstructural evolution during continuous heating experiments has been studied for two C-Mn steels with carbon contents in the range 0.35 to 0.45 wt pct using optical microscopy, scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). It is shown that the formation of the austenitic phase is possible in pearlite as...journal article 2007
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- Krielaart, G.P. (author), Sietsma, J. (author), Van der Zwaag, S. (author) journal article 1997
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Ghodrat, S. (author), Riemslag, T.A.C. (author), Kestens, L.A.I. (author), Petrov, R.H. (author), Janssen, M. (author), Sietsma, J. (author)In cylinder heads of compacted graphite iron (CGI), the heating and cooling cycles can lead to localized cracking due to thermomechanical fatigue (TMF). Traditionally, TMF behavior is studied by thermal cycling of smooth specimens. The resulting number of cycles to failure (Nf) constitutes a single parameter that can be used to predict actual...journal article 2012
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- Ruitenberg, G. (author), De Hey, P. (author), Sommer, F. (author), Sietsma, J. (author) journal article 1997
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Rivera-Diaz-Del-Castillo, P.E.J. (author), Sietsma, J. (author), Van der Zwaag, S. (author)A model for predicting the conditions under which ferrite/pearlite band formation occurs, and therefore the conditions in which it can be avoided in steels, has been developed. The model requires as input the alloy composition and microchemical segregation wavelength, and provides in turn the homogenization temperature and time in which the...journal article 2004
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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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- Duine, P.A. (author), Sietsma, J. (author), Thijsse, B.J. (author), Pusztai, L. (author) journal article 1994
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- van Ee, L.D. (author), Thijsse, B.J. (author), Sietsma, J. (author) journal article 1998
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Tirumalasetty, G.K. (author), Van Huis, M.A. (author), Kwakernaak, C. (author), Sietsma, J. (author), Sloof, W.G. (author), Zandbergen, H.W. (author)Uniaxial straining experiments were performed on a rolled and annealed Si-alloyed TRIP (transformation-induced plasticity) steel sheet in order to assess the role of its microstructure on the mechanical stability of austenite grains with respect to martensitic transformation. The transformation behavior of individual metastable austenite grains...journal article 2012
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Van Bohemen, S.M.C. (author), Sietsma, J. (author), Van der Zwaag, S. (author)The formation mechanisms of two hcp ? phase morphologies in Ti-4.5Fe-6.8Mo-1.5Al have been investigated by optical microscopy (OM), atomic force microscopy (AFM), electron probe microanalysis (EPMA) and dilatometry. At relatively high temperatures primary ? forms predominantly on prior bcc ? grain boundaries, whereas at lower temperatures so...journal article 2006
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Savran, V.I. (author), Offerman, S.E. (author), Sietsma, J. (author)Austenite nucleation and growth is studied during continuous heating using three-dimensional X-ray diffraction (3-D XRD) microscopy at the European Synchrotron Radiation Facility (ESRF) (Grenoble, France). Unique in-situ observations of austenite nucleation and growth kinetics were made for two commercial medium-carbon low-alloy steels (0.21 and...journal article 2010