Pultrum, B.B., Van Der Jagt, E.J., Van Westreenen, H.L., Van Dullemen, H.M., Kappert, P., Groen, H., ...
AIM: In this feasibility study we investigated whether magnetic resonance imaging (MRI) with ultrasmall superparamagnetic iron oxide (USPIO) can be used to identify regional and distant lymph nodes,...
R. G. Thiessen, J. Sietsma, I. M. Richardson
Abstract: This work presents a unique approach for the modelling of the austenitisation of martensite in dual-phase steels within the phase-field method. Driving forces for nucleation and growth are...
Nucleation and variant selection of secondary alpha plates in a beta Ti alloy (2008)
VAN BOHEMEN, SMC, KAMP, A, Petrov, Roumen, KESTENS, LAI, SIETSMA, J
Discussion to: Grain nucleation and growth during phase transformations. Authors' reply (2004)
Aaronson, H.I., Purdy, G.R., Offerman, S.E., Van Dijk, N.H., Sietsma, J., ...
The austenite recrystn. kinetics in the intercrit. region of a C-Mn steel is investigated by means of stress relaxation tests. It is found that the Avrami exponent, n, decreases significantly with...
Effect of inhomogeneous deformation on the recrystallization kinetics of deformed metals (2004)
In this paper, the Johnson-Mehl-Avrami-Kolmogorov equation, modified by Rollett et al. (1989) to take the heterogeneity of recrystn. into account, was used to derive anal. equations to calc. the...
The austenite recrystallization kinetics in the intercritical region of a C-Mn steel is investigated by means of stress relaxation tests. It is found that the Avrami exponent, n, decreases...
It was found that a ferrite-to-austenite retransformation can take place during isothermal holding after deformation in 0.19 pct C-1.46 pct Mn steel at higher intercritical temperatures, but it was...
Offerman, S.E., Van Dijk, N.H., Sietsma, J., Lauridsen, E.M., Margulies, L., ...
This paper is written as a reaction to the discussion by Aaronson et al. on our conclusion that the activation energy for ferrite nucleation during the austenite decomposition in medium carbon steel...
Offerman, S.E., Van Dijk, N.H., Sietsma, J., Lauridsen, E.M., Margulies, L., Grigull, S., ...
A simplified grain growth model is presented for the transition from non-overlapping to overlapping diffusion fields of growing neighboring grains during partitioning solid-state transformations in...
Influence of intercritical deformation on microstructure of TRIP steels containing Al (2004)
Papaefthymiour, S., Bleck, W., Kruijver, S., Sietsma, J., Zhao, L.
The influence of intercritical deformation on the microstructure development of a TRIP steel has been investigated by the use of deformation dilatometry, X-ray diffraction, and metallography. The...
A model for ferrite/pearlite band formation and prevention in steels (2004)
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...
A concise model for mixed-mode phase transformations in the solid state (2004)
Using a Zener-like approach, the character of partitioning mixed-mode phase transformations in the solid state is shown to be governed by a single parameter Z. The parameter is proportional to the...
Smith, A., Miroux, A., Luo, H., Sietsma, J.
The softening kinetics of a 0.19 wt% C 1.5 wt% Mn steel deformed at two intercrit. temps. have been characterised using the stress relaxation technique. Recrystn. of intercrit. austenite has been...
Recovery processes in the ferrite phase in C-Mn steel (2004)
Smith, A., Luo, H.W., Hanlon, D.N., Sietsma, J.
The static recovery kinetics in ferrite were investigated by means of the stress relaxation technique. Samples were deformed in compression for a variety of temperatures, strains and strain rates.The...
Van Dijk, N.H., Offerman, S.E., Klaasse, J.C.P., Sietsma, J.
The isothermal transformation kinetics of the austenite to pearlite transformation in (nearly) eutectoid steel was studied by in situ magnetisation measurements at high temperatures. In eutectoid...
Neutron depolarisation study of the austenite grain size in TRIP steels (2004)
Van Dijk, N.H., Zhao, L., Rekveldt, M.T., Fredrikze, H., Tegus, O., Brueck, E., ...
We have performed combined neutron depolarisation and magnetization measurements in order to obtain an in situ detn. of the av. grain size and vol. fraction of the retained austenite phase in TRIP...
Kruijver, S.O., Zhao, L., Sietsma, J., Offerman, S.E., Van Dijk, N.H., Lauridsen, E.M., ...
In-situ tensile deformation tests have been performed on a high Al TRIP steel (composition 0.26 wt. % Si, 1.5 wt. % Mn, and 1.8 wt. % Al) displaying the transformation-induced plasticity (TRIP)...
The mechanical stability of austenite in TRIP steel observed by 3D X-ray microdiffraction (2003)
Kruijver, S.O., Zhao, L., Sietsma, J., Lauridsen, E.M., Poulsen, H.F., Offerman, S.E., ...
In-situ tensile deformation tests were performed on a transformation-induced plasticity (TRIP) steel, while monitoring the martensitic transformation from retained austenite (g) to martensite (a') by...
Effect of intercritical deformation on bainite formation in Al-containing TRIP steel (2003)
Luo, H.W., Zhao, L., Kruijver, S.O., Sietsma, J.
The Influence of intercritical deformation, cooling rate and prior austenite grain size on bainite formation were investigated by dilatometry tests. Intercritical deformation (0-40%) performed in...
Mecozzi, M.G., Sietsma, J., Apel, M., Schaffnit, P., Steinbach, I.
This paper deals with the kinetics of the austenite to ferrite (gamma --> alpha) transformation during controlled cooling of C-Mn steel. A phase field model is used to simulate the gamma --> alpha...
Acoustic-emission investigations on the austenite decomposition in a medium-carbon steel (2003)
Mertens, A., Hermans, M.J.M., Sietsma, J.
Continuous cooling of the austenitic phase is important in controlling the microstructure and properties of steel. At high cooling rates, the initial formation of allotriomorphic ferrite undergoes a...
Offerman, S.E., Van Dijk, N.H., Rekveldt, M.T., Sietsma, J., ...
Three-dimensional neutron depolarization experiments were performed to study in situ the isothermal phase transformation from austenite to pearlite in the bulk of an eutectoid steel. It is shown that...
Offerman, S.E., Van Wilderen, L., Van Dijk, N.H., Sietsma, J., Rekveldt, M.T.
The evolution of the microstructure during the isothermal austenite/pearlite transformation in a nearly eutectoid steel was studied by the three-dimensional neutron depolarization technique, which...
Micromechanical damage simulations of TRIP steels (2003)
Papaefthymiou, S., Bleck, W., Prahl, U., Acht, C., Sietsma, J.
Economical and ecological considerations are the driving force in applying newly developed high strength multiphase steels combining high strength and, good formability in automotive applications....
Austenite decomposition: modelling and measuring at the level of individual grains (2003)
Sietsma, J., Offerman, E., Van Dijk, N.
Current status of introducing the individual austenite grain as an important parameter in kinetic models for austenite decompn. is discussed. Unique ferrite growth and austenite shrinkage X-ray data...
Van Leeuwen, Y., Luinenburg, A.W., Onink, M., Sietsma, J.
The ability to control the mechanical properties of hot rolled steel strip depends strongly on the knowledge of the metallurgical processes taking place during production. On the ran-out table of a...
During the austenite-ferrite phase transformation the excess amount of carbon that can not be dissolved in the growing ferrite phase accumulates in the austenite phase ahead of the moving interface....
Zhao, L., Vermolen, F.J., Sietsma, J.
The present work analyses the total free energy of the material during the martensitic transformation. A general expression for the martensite fraction as a function of temperature is derived,...
SANS experiments on Nb(C,N) and MnS precipitates in HSLA steel (2002)
Van Dijk, NH, Offerman, SE, Bouwman, WG, Rekveldt, MTh, Sietsma, J, ...
High temperature SANS experiments on Nb(C,N) and MnS precipitates in HSLA steel (2002)
Van Dijk, N H, Offerman, S E, Bouwman, W G, Rekveldt, M Th, Sietsma, J, ...
Bodin, A., Woning, L., Sietsma, J.
The texture development during the phase transformation of austenite to ferrite was studied by means of in-situ high-temperature X-ray diffraction and compared to results obtained with conventional...
Texture and microstructure development during intercritical rolling of low-carbon steels (2002)
Laboratory rolling trials have been performed to investigate the development of microstructure and crystallographic texture during and after intercritical rolling. The finishing temperature was...
The influence of nitrogen on the austenite/ferrite interface mobility in Fe 1at.%Si (2002)
The relation between the nitrogen content and the mobility of the austenite/ferrite interface during the austenite to ferrite transformation have been investigated. Samples of an Fe-1at.%Si alloy...
In situ observations on the austenite stability in TRIP-steel during tensile testing (2002)
Kruijver, S., Zhao, L., Sietsma, J., Offerman, E., Van Dijk, N., Margulies, L., ...
In-situ deformation tests have been performed on a steel displaying the transformation-induced plasticity (TRIP) effect, while monitoring the phase transformation by means of X-ray diffraction. A...
Ferrite/pearlite band formation in hot rolled medium carbon steel (2002)
Offerman, S.E., Van Dijk, N.H., Rekveldt, M.T., Sietsma, J.
The influence of the microsegregation of Mn, Si, and Cr on the austenite decomposition during isothermal transformations in hot rolled medium carbon steel has been studied by neutron depolarisation,...
Grain nucleation and growth during phase transformations (2002)
Offerman, S.E., Van Dijk, N.H., Sietsma, J., Grigull, S., Lauridsen, E.M., Margulies, L., ...
The mechanical properties of polycrystalline materials are largely determined by the kinetics of the phase transformations during the production process. Progress in x-ray diffraction instrumentation...
Van Der Wolk, P.J., Wang, J.J., Sietsma, J.
A neural network model for the calculation of the phase regions of the continuous cooling transformation (CCT) diagram of engineering steels has been developed. The model is based on experimental CCT...
Van Der Wolk, P.J., Wang, J.J., Sietsma, J.
The neural network model of Van der Wolk et al. [1] describes the effect of composition on the phase regions of the continuous cooling transformation (CCT) diagram, yet does not consider the...
Zhao, L., Kruijver, S.O., Sietsma, J., Tsuzaki, K.
Stability of retained austenite is the key issue to understand transformation-induced plasticity (TRIP) effect. In this work, both thermal stability and mechanical stability are investigated by...
High temperature SANS experiments on Nb(C,N) and MnS precipitates in HSLA steel (2002)
Van Dijk, N.H., Offerman, S.E., Bouwman, W.G., Rekveldt, M.T., Sietsma, J., ...
The volume distribution of precipitates in high-strength low-alloy (HSLA) steels has been studied using small-angle neutron scattering (SANS) at high temperatures. Three samples with different...
SANS experiments on Nb(C, N) and MnS precipitates in HSLA steel (2002)
Van Dijk, N.H., Offerman, S.E., Bouwman, W.G., Rekveldt, M.T., Sietsma, J., ...
The size distribution of precipitates in high-strength low-alloy (HSLA) steels has been studied using small-angle neutron scattering (SANS) at high temperatures. Three samples with different niobium...
Neutron depolarization study of the austenite/pearlite phase transformation in steel (2002)
Van Wilderen, L., Offerman, S.E., Van Dijk, N.H., Rekveldt, M.T., Sietsma, J.
Three-dimensional neutron depolarization experiments have been performed to study in situ the isothermal phase transformation from austenite to pearlite in eutectoidic steel. The interaction between...
Quantitative dilatometric analysis of intercritical annealing in a low-silicon TRIP steel (2002)
Zhao, L., Kop, T.A., Rolin, V., Sietsma, J., Mertens, A., Jacques, P.J., ...
In this work, an evaluation method to calculate the austenite fraction during continuous heating and isothermal annealing from dilatometric data is proposed. By means of a single reference...
Implementation of the Bergstrom work-hardening model into an FEM code enabled simulating the deformation behaviour during intercritical deformation of a low-carbon steel. The simulations revealed...
Laboratory rolling trials have been performed to investigate the development of microstructure during and after intercritical rolling. The finishing temperature was varied over a wide range, and...
The effect of high-temperature plastic deformation of the austenitic phase (gamma) on the subsequent phase transformation to ferrite (alpha) has been experimentally investigated, and modelled using a...
A modeling approach to account for the effect of deformation on the austenite to ferrite transformation is described. In this approach the stored energy of deformation resulting from the formation of...
Dilatation measurements were carried out on cylindrical specimens taken from the longitudinal and the normal directions of hot rolled C - Mn steel strip, giving rather different results for the heat...
Dilatometric analysis of phase transformations in hypo-eutectoid steels (2001)
Dilatometry is a useful technique to obtain experimental data concerning transformation kinetics in ferrous alloys. This technique is commonly used in cooling experiments to study the austenite...
Kop, T.A., Remijn, P.G.W., Svetchnikov, V., Sietsma, J.
The dependence of the transformation kinetics of an HSLA steel and related C-Mn steels on the austenitisation conditions have been investigated using calorimetry and dilatometry. It is observed that...
Korevaar, B.M., Coorens, S., Fu, Y., Sietsma, J.
This paper describes an investigation into the effects of nitriding, denitriding, and renitriding, on the rotating bending fatigue strength of notched specimens of the quenched and tempered steels...
Domain size determination of granular ferromagnetic systems with neutron depolarization (2001)
Van Dijk, N.H., Rekveldt, M.T., Sietsma, J.
The depolarization of a polarized neutron beam after transmission through a granular magnetic medium is related to the size and orientation of the ferromagnetic domains. Unfortunately, this...
The - transformation kinetics of low carbon steels under ultra-fast cooling conditions (2001)
Van Leeuwen, Y., Onink, M., Sietsma, J.
Current evolutions in the processing techniques of hot rolled steel sheet, like the development of an ultra fast cooling unit which cools the material after the final rolling step, stretch the domain...
Zhao, L., Van Dijk, N.H., Bruck, E., Sietsma, J.
The accurate determination of the volume fraction of retained austenite is of great importance for the optimization of transformation induced plasticity (TRIP) steels. In this work, two...
Kop, T.A., Van Leeuwen, Y., Sietsma, J.
The kinetics of the phase transformation between the high temperature FCC-phase austenite and the low temperature BCC-phase ferrite as it occurs during controlled cooling of hot roiled low carbon...
3D neutron depolarization experiments on the gamma/alpha phase transformation in steel (2000)
Offerman, S.E., Van Dijk, N.H., Rekveldt, M.T., Sietsma, J.
Three-dimensional neutron depolarization experiments have been performed in order to study the isothermal phase transformation from austenite (gamma-Fe) into ferrite (alpha-Fe) in medium-carbon...
Van Dijk, N.H., Rekveldt, M.T., Sietsma, J.
A general three-dimensional model for the development of microstructure in metals by diffusion-controlled processes has been constructed. The model has been applied to the austenite (gamma-Fe) to...
Field-dependent neutron depolarization study of the ferrite formation in medium-carbon steels (2000)
Velthuis, S., Van Dijk, N.H., Rekveldt, M.T., Sietsma, J.
Neutron depolarization experiments have been performed on the ferrite and pearlite phase transformations of the medium-carbon C60 and C35 steels. The interaction of the polarized neutron beam with...
On the mobility of the austenite-ferrite interface in Fe-Co and Fe-Cu (2000)
Vooijs, S.I., Van Leeuwen, Y., Sietsma, J.
The kinetics of diffusional transformations in steels depend on a large number of parameters, such as grain geometry, nucleation behavior, and growth kinetics. An essential step in the process is the...
Phase transformations and microstructural evolution in aluminum-containing TRIP steels (2000)
Aluminum-contg. transformation induced plasticity (TRIP) steels contg. 0.2 wt.% carbon and 1.5 wt.% manganese and a variable aluminum concn., ranging from 0.96 wt.% to 1.8 wt.%, are investigated. The...
A flow stress model for the intercritical deformation of low-carbon steels (1999)
The intercrit. deformation of 2 steels, a low-C and a C-Mn steel, was analyzed using the Bergstrom and the Ludwik-Hollomon model. The models were applied to interpret the results of uniaxial...
Microstructure and texture development during and after intercritical rolling of LC-steels (1999)
The paper describes the development of the microstructure and crystallog. texture during and after intercrit. lab. rolling of low C steels. The mean flow stress during intercrit. rolling does not...
The effect of plastic deformation of the austenitic phase of a C-Mn steel on the subsequent austenite to ferrite transformation was studied. Exptl. detd. transformation data obtained by deformation...
Ferrite growth from austenite in C-Mn steels during continuous cooling (1999)
Experiments are carried out to examine the ferrite formation in four lean construction steels of low carbon and low alloy contents during continuous cooling. The variation of the heat capacity during...
Neutron depolarization study of phase transformations in steel (1999)
Van Dijk, N.H., Rekveldt, M.T., Sietsma, J.
Three-dimensional neutron depolarization experiments have been performed in order to study the phase transformations from austenite (gamma-Fe) into ferrite (alpha-Fe) and cementite (Fe3C) in two...
Van Leeuwen, Y., Kop, T.A., Sietsma, J., Busso, E., Cailletaud, G., ...
The mechanical properties of steel are determined by the microstructure that develops during the production process and is a joint result of effects of chemical composition and of heat treatment....
Kop, T.A., Remijn, P.G.W., Sietsma, J., Rodriguez, I., Gutierrez, I., ...
An experimental study on the effect of the austenitisation temperature on the austenite decomposition for an Nb-microalloyed steel is performed by means of Differential Thermal Analysis. The start...
Ferrite nucleation and growth in a medium-carbon steel studied by neutron depolarization (1998)
The neutron depolarization technique was used for simultaneous observation of the grain size and vol. fraction of ferrite and pearlite forming from austenite in a 0.364 wt.% C steel at different...
Root, J.H., Sietsma, J., Rekveldt, M.T.
The lattice parameters of Fe-1% Cu, Fe-2% Cu, Fe-1% Co, and Fe-2% Co binary alloys were determined by means of neutron diffraction at temperatures around the austenite-ferrite phase transformation...
Intelligent processing in a hot rolling mill for structural steels (1998)
Van Der Wolk, P.J., Dorrepaal, C., Sietsma, J.
To control the properties of a steel, both its composition and the applied heat treatment are of paramount importance. During the hot rolling process the cooling process is of main importance to...
The effect of geometrical assumptions in modeling solid-state transformation kinetics (1998)
Van Leeuwen, Y., Vooijs, S., Sietsma, J.
In the quest for the ideal transformation model describing the austenite decomposition in steel, emphasis shifts from empirical to physical models. This has resulted in the widely used description of...
Kop, T.A., Tichelaar, F.D., Sietsma, J.
This paper presents the results of an in-situ Transmission Electron Microscopic investigation of the austenite to ferrite transformation in a binary Fe-0.75 wt.% Mn alloy. The a/g interface velocity...
Ferrous phase transformation kinetics: a combined dilatometric-calorimetric approach (1997)
Dilatometry and DTA are often used to measure the kinetics of the phase transformations from austenite to ferrite and pearlite in C-Mn steels and other lean construction steels. It is, however, by no...
The transformation kinetics of construction steels; a combined dilatometric and DTA approach (1997)
Using a model function for the transformation of austenite to ferrite and pearlite in a low-carbon steel in a cooling expt., it is shown that straightforward anal. of dilatometry and DTA data can...
The growth of ferrite during the decomposition of supersaturated austenite in binary Fe-C alloys is studied using a numerical model that allows non-equilibrium conditions at the moving...
In-situ studies of the ferrite nucleation and growth in C-Mn steels (1997)
Sietsma, J., Maas, F.A.M., Rekveldt, M.T.
In-Situ Neutron Depolarization (ND) measurements were performed during continuous cooling at moderate cooling rates for several C-Mn steels. During cooling, the phase transformations from austenite...
Phase transformations in steels studied using neutron depolarization (1997)
Maas, F.A.M., Rekveldt, M.T., Sietsma, J.
Neutron Depolarization expts. of the austenite to ferrite phase transformation in C60 and C35 steels are presented. The ferrite fraction and the av. ferrite particle size are detd. during isochronal...
Neutron depolarization as a tool for studying phase transformations in steels (1997)
Neutron depolarization experiments of austenite to ferrite phase transformations in C60 steels are presented. The ferrite fraction and the average ferrite particle size, determined during a two-step...
Van Leeuwen, Y., Sietsma, J., Vooijs, S.
Since the austenite-to-ferrite phase transformations in Fe-Co and Fe-Cu (1 and 2 at.%) are of a massive type, these transformations are used to study the interface mobility sep. from the long-range...
Using neural networks for underwater target ranging (1993)
Underwater weapons often have to range their targets from complex and highly variable signals, referred to as signatures. If artificial neural networks are applied to this task, the complexity of the...
Using neural networks for underwater target ranging (1993)
Underwater weapons often have to range their targets from complex and highly variable signals, referred to as signatures. If artificial neural networks are applied to this task, the complexity of the...
Using neural networks for underwater target ranging (1993)
Underwater weapons often have to range their targets from complex and highly variable signals, referred to as signatures. If artificial neural networks are applied to this task, the complexity of the...
Using neural networks for underwater target ranging (1993)
Underwater weapons often have to range their targets from complex and highly variable signals, referred to as signatures. If artificial neural networks are applied to this task, the complexity of the...
Neural net pruning - why and how (1988)
A continuing question in neural net research is the size of network needed to solve a particular problem. If training is started with too small a network for the problem no learning can occur. The...
Neural net pruning - why and how (1988)
A continuing question in neural net research is the size of network needed to solve a particular problem. If training is started with too small a network for the problem no learning can occur. The...
Neural net pruning - why and how (1988)
A continuing question in neural net research is the size of network needed to solve a particular problem. If training is started with too small a network for the problem no learning can occur. The...
Neural net pruning - why and how (1988)
A continuing question in neural net research is the size of network needed to solve a particular problem. If training is started with too small a network for the problem no learning can occur. The...