Journal articles: 'DICTRA'

1

Suehiro, Masayoshi, and John Ågren. "A Software to Simulate Transformation, "DICTRA"." Materia Japan 38, no. 8 (1999): 629–32. http://dx.doi.org/10.2320/materia.38.629.

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2

Engström, Anders, Johan Bratberg, Qing Cheng, Lars Höglund, and Paul Mason. "Application of Thermodynamic and Kinetic Modeling to Diffusion Simulations in Nickel-Base Superalloy Systems." Advanced Materials Research 278 (July 2011): 198–203. http://dx.doi.org/10.4028/www.scientific.net/amr.278.198.

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This paper presents a brief review, followed by some new results from recent diffusion simulations in Ni-base superalloy systems, performed by means of a thermodynamic and kinetic modeling approach as taken in the commercial finite-difference code DICTRA. The DICTRA code solves the multi-component diffusion equations, combining assessed thermodynamic and kinetic data in order to determine the full composition dependent interdiffusion matrix. The link between fundamental physics based models and critically assessed data allows simulations to be performed with realistic conditions on alloys of practical importance. Emphasis in this paper is on modeling and simulation of interdiffusion occurring between NiAl coatings and Ni-base superalloy substrates. For this purpose we have used the so-called homogenization approach to diffusion in multi-phase systems, recently implemented into the DICTRA software. The simulation results have been validated against experimental data and the agreement is very satisfactory given the complexity of the problem.

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3

Strandlund, Henrik, and Henrik Larsson. "Diffusion Process Simulations - An Overview of Different Approaches." Defect and Diffusion Forum 233-234 (December 2004): 97–114. http://dx.doi.org/10.4028/www.scientific.net/ddf.233-234.97.

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Some different approaches to diffusion process simulations are briefly presented. Their varying areas of applicability are discussed. Example simulations using the phase-field method, the DICTRA software, and random-walk based approaches are presented.

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4

Shi, Pinfang, Anders Engström, Lars Höglund, Bo Sundman, and John Ågren. "Thermo-Calc and DICTRA Enhance Materials Design and Processing." Materials Science Forum 475-479 (January 2005): 3339–46. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3339.

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5

Andersson, J.-O., Thomas Helander, Lars Höglund, Pingfang Shi, and Bo Sundman. "Thermo-Calc & DICTRA, computational tools for materials science." Calphad 26, no. 2 (June 2002): 273–312. http://dx.doi.org/10.1016/s0364-5916(02)00037-8.

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6

Borgenstam, Annika, Lars Höglund, John Ågren, and Anders Engström. "DICTRA, a tool for simulation of diffusional transformations in alloys." Journal of Phase Equilibria 21, no. 3 (May 2000): 269–80. http://dx.doi.org/10.1361/105497100770340057.

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7

Larsson, Henrik, and Lars Höglund. "Multiphase diffusion simulations in 1D using the DICTRA homogenization model." Calphad 33, no. 3 (September 2009): 495–501. http://dx.doi.org/10.1016/j.calphad.2009.06.004.

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8

Shi, Ping Fang, Anders Engström, Bo Sundman, and John Ågren. "Thermodynamic Calculations and Kinetic Simulations of some Advanced Materials." Materials Science Forum 675-677 (February 2011): 961–74. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.961.

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The Thermo-Calc and DICTRA software/database/programming-interface packages, through many successful applications in the fields of Computational Thermodynamics and Kinetics, have tremendously contributed to quantitative conceptual design and processing of various advanced materials. Materials scientists and engineers can efficiently apply such unique and comprehensive tools in calculating material properties, predicting material structures and simulating material processes, which are of wide-ranging industrial and academic importance.

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9

Dahl, K. V., J. Hald, and A. Horsewell. "Interdiffusion Between Ni-Based Superalloy and MCrAlY Coating." Defect and Diffusion Forum 258-260 (October 2006): 73–78. http://dx.doi.org/10.4028/www.scientific.net/ddf.258-260.73.

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Interdiffusion at the interface between a Co-36.5Ni-17.5Cr-8Al-0.5Y, MCrAlY coating and the underlying IN738 superalloy was studied in a large matrix of specimens isothermally heat treated for up to 12,000 hours at temperatures 875°C, 925°C or 950°C. Modelled results using the finite difference software DICTRA was compared with experimental average composition profiles measured across the interface using a new experimental approach.

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10

Nilsson, Jan Olof. "Prediction of Properties in Type 347 Austenitic Stainless Steel after Long-Term Service at High Temperatures." Materials Science Forum 539-543 (March 2007): 4920–25. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.4920.

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The evolution of microstructure during production and elevated temperature service of type 347 austenitic stainless steel in the temperature range 700-800°C was modelled using commercial software packages such as Thermo-Calc and DICTRA and characterized using various microscopical techniques. The growth and coarsening of niobium carbonitrides and σ- phase were modelled as well as nitrogen uptake. Good agreement between predictions and microstructural observations was found.

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11

Inden, Gerhard. "Diffusion and Phase Transformations in Multi-Component Systems." Defect and Diffusion Forum 263 (March 2007): 11–20. http://dx.doi.org/10.4028/www.scientific.net/ddf.263.11.

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The simulation of diffusion-controlled transformations in multi-component systems is presented using the software DICTRA. It is shown that not only stable phases precipitate during heat treatments, but also metastable phases. These phases appear in the microstructure for a certain interim time period, which can be predicted by the simulation. Various reaction regimes are possible: local equilibrium which is a slow reaction, local equilibrium with no partitioning which is a fast reaction, para-equilibrium which is a regime with no diffusion at all of the substitutional elements. The transition between the various regimes leads to the development of precipitation stases.

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12

Zlámal, Bronislav, Rudolf Foret, Jiří Buršík, and Milan Svoboda. "Microstructural Stability of Dissimilar Weld Joint of Creep-Resistant Steels with Increased Nitrogen Content at 500 – 900 °C." Defect and Diffusion Forum 263 (March 2007): 195–200. http://dx.doi.org/10.4028/www.scientific.net/ddf.263.195.

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The structural changes taking place in the dissimilar laboratory welds of 6CrMoV 8-3-2 (T25), being under development, and modified X12CrMoVNb 10-1 (P91) nitrided steels annealed at temperatures of 500 – 900 °C have been subject of study. Carbon and nitrogen redistribution measurement by the EPMA method was complemented with detailed structural analysis aimed at the phase profiles and chemical composition of coexisting carbides and carbonitrides in particular regions of the weld joint. Results of experimental work were compared with thermodynamic and kinetic modeling using the DICTRA software. A very good agreement between the modeling and the experiments was observed.

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13

Turpin, T., J. Dulcy, and M. Gantois. "Prediction of phase distribution and chemical composition during gas carburizing of stainless steels." Journal de Physique IV 120 (December 2004): 249–57. http://dx.doi.org/10.1051/jp4:2004120029.

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This article reports a theoretical and experimental study aiming at reducing gas carburizing experiments on stainless steels. This work was carried out to show the advantages of numerical calculations to simulate phase transformations during the gas carburizing process of high alloyed steels. The use of Thermo-Calc and Dictra software allows the metallurgist to predict the optimum thermochemical and heat treatments which are necessary to obtain an accurate carbon profile in a stainless steel. Moreover, the phase distribution and chemical composition can be followed as a function of time and/or distance to gas-solid interface.

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14

Schneider, A., C. Stallybrass, J. Konrad, A. Kulgemeyer, H. Meuser, and S. Meimeth. "Formation of primary TiN precipitates during solidification of microalloyed steels – Scheil versus DICTRA simulations." International Journal of Materials Research 99, no. 6 (June 2008): 674–79. http://dx.doi.org/10.3139/146.101689.

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15

Garcia, José, Greta Lindwall, Orlando Prat, and Karin Frisk. "Kinetics of formation of graded layers on cemented carbides: Experimental investigations and DICTRA simulations." International Journal of Refractory Metals and Hard Materials 29, no. 2 (March 2011): 256–59. http://dx.doi.org/10.1016/j.ijrmhm.2010.11.003.

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16

Eriksson, Robert, Kang Yuan, Sten Johansson, and Ru Lin Peng. "Microstructure-Based Life Prediction of Thermal Barrier Coatings." Key Engineering Materials 592-593 (November 2013): 413–16. http://dx.doi.org/10.4028/www.scientific.net/kem.592-593.413.

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The widespread use of thermal barrier coatings (TBC) in gas turbines stresses the importance of accurate life prediction models for TBCs. During service, the TBC may fail due to thermal fatigue or through the formation of thermally grown oxides (TGOs). The current paper presents a Thermo-Calc/Dictra-based approach to life prediction of isothermally oxidised atmospheric plasma sprayed (APS) TBCs. The β-phase depletion of the coating was predicted and compared to life prediction criteria based on TGO thickness and Al content in the coating. All tried life models underestimated the life of the coating where the β-depletion-based model was the most conservative.

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17

Li, Hui, Zhen Li Mi, Xiao Lei Zhang, Di Tang, and Yi De Wang. "Calculation and Analysis of Diffusion Kinetics of Alloying Elements in Bearing Steel." Advanced Materials Research 815 (October 2013): 216–20. http://dx.doi.org/10.4028/www.scientific.net/amr.815.216.

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In order to detect the diffusion law of alloying elements in 0.95c-1.45cr-0.35mn-0.25si bearing steel during annealing process,the database of tcfe7 and mobfe of dictra software were used to calculate the diffusion kinetics. The results show that c atoms diffuse rapidly in single fcc phase field and at last uniform,temperature and holding time have no significant influence on them;cr,si,and mn has the same diffusion mechanism,the initial solidifying field has lower solute than the subsequent,and has slight change after solidification. The improvement of segregation factor (cr) at 1300°C for 5h is better than at 1050°C, 1200°C for 10h.

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18

Gong, W., L. Zhang, M. Ode, H. Murakami, and C. Zhou. "Experimental investigation and computer simulation of diffusion in Pt-coated bulk Ni." Journal of Mining and Metallurgy, Section B: Metallurgy 46, no. 2 (2010): 153–60. http://dx.doi.org/10.2298/jmmb1002153g.

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The concentration profiles of thin-film Pt/bulk Ni coatings annealed at 1150, 1250 and 1300?C for different time were measured by means of electron probe microanalysis. The corresponding interdiffusion coefficients were then determined using the thin-film solution. The calculated concentration profiles based on the presently obtained interdiffusion coefficients agree well with the experimental ones, but better at a higher temperature or a longer time. The comparison between the presently measured concentration profiles and the DICTRA simulated ones indicates that it is promising to apply the well-established atomic mobility databases due to bulk diffusion information in coating systems with some simple modifications for diffusivities.

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19

Morais, Luara da Costa, and Rodrigo Magnabosco. "Experimental investigations and DICTRA® simulation of sigma phase formation in a duplex stainless steel." Calphad 58 (September 2017): 214–18. http://dx.doi.org/10.1016/j.calphad.2017.07.006.

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20

Ma, Li, Tao Jia, Xiu Hua Gao, and Run Ni. "Mechanism of Cementite Spheroidization from Different Initial Microstructures in Fe-0.65C-2.33Mn Alloy." Key Engineering Materials 815 (August 2019): 107–13. http://dx.doi.org/10.4028/www.scientific.net/kem.815.107.

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The spheroidization mechanism from different initial microstructures during spheroidizing heat treatment was studied in Fe-0.68C-2.33Mn alloy. Two types of initial microstructures, i.e. pearlite and martensite, were obtained by varying the cooling rate. The microstructure and property evolution during spheroidizing annealing was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The DICTRA software, assuming local equilibrium conditions, was used to simulate the carburizing process of different initial microstructures through different cooling rate. The results indicate that the spheroidization mechanism of cementite was related to the initial microstructures and the smaller lamellar spacing of pearlite inhibited the coarsening of cementite, resulting in the size of cementite smaller than that of martensite as the initial structure.

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21

Chen, Qing, Anders Engström, Lars Höglund, Henrik Strandlund, and Bo Sundman. "Thermo-Calc Program Interface and Their Applications - Direct Insertion of Thermodynamic and Kinetic Data into Modelling of Materials Processing, Structure and Property." Materials Science Forum 475-479 (January 2005): 3145–48. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3145.

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Thermodynamic and kinetic data are generally essential for quantitative modeling of materials processing, structure, and property. Thermo-Calc program interfaces, including TQ, TCAPI, and TC MATLAB Toolbox, provides a hierarchy of APIs for application programmers to access thermodynamic and kinetic data via the kernel of Thermo-Calc and DICTRA, the most widely used software and database system for multi-component phase equilibrium and phase transformation calculations. With these program interfaces, variation of thermodynamic and kinetic properties can be directly obtained in real time as the local temperature, pressure, or composition changes. The structure and usage of the Thermo-Calc program interfaces will be introduced in this article. Successful application examples will be illustrated.

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22

Mei, Paulo Roberto, S. P. Moreira, A. D. S. Côrtes, D. S. Silva, and F. C. Marques. "Back Diffusion during Zone Melting of Metallurgical Silicon." Defect and Diffusion Forum 326-328 (April 2012): 43–47. http://dx.doi.org/10.4028/www.scientific.net/ddf.326-328.43.

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As the silicon melting point is very high (1414 °C), the temperature in the solid fraction, near the interface solid/liquid during solidification is also high and this can provoke a solute redistribution in the solidified portion. This phenomena is called back diffusion. So, it is important to estimate the potential of back diffusion during the solidification processes. This calculation is complex and there is commercial software, such as DICTRA, to do this in binary alloys. For zone melting, a simple method to predict the extension of the back diffusion is not available. In this study, it was developed a simple method to evaluate the back diffusion during zone melting, which does not require computational calculation.

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23

Ramesh Babu, Shashank, Matias Jaskari, Antti Jarvenpää, Thomas Paul Davis, Jukka Kömi, and David Porter. "Precipitation Versus Partitioning Kinetics during the Quenching of Low-Carbon Martensitic Steels." Metals 10, no. 7 (June 27, 2020): 850. http://dx.doi.org/10.3390/met10070850.

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Low-carbon, low-alloy steels undergo auto-tempering and carbon partitioning to austenite during quenching to martensite. The microstructures of two such steels quenched at two cooling rates have been evaluated using electron microscopy to characterise lath and carbide precipitate morphologies, and the results have been compared with theoretical predictions based on the Thermo-Calc modules DICTRA and TC-Prisma. The modelling tools predicted the carbon depletion rates due to diffusion from the bcc martensite laths into austenite and the precipitation of cementite in the ferrite matrix. The predictions showed a satisfactory agreement with the metallographic results, indicating that the Thermo-Calc based software can aid in the design of new low-carbon martensitic steels.

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24

Zhu, W. J., J. Wang, L. B. Liu, H. S. Liu, Z. P. Jin, and C. Leinenbach. "Modeling and simulation of the TiC reaction layer growth during active brazing of diamond using DICTRA." Computational Materials Science 78 (October 2013): 74–82. http://dx.doi.org/10.1016/j.commatsci.2013.05.025.

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25

da Costa Morais, Luara, Flavio Beneduce, Rodrigo Magnabosco, and Tiago Ramos Ribeiro. "Use of DICTRA® simulations to support carbide particle growth study in NbC-Ni cemented carbide." International Journal of Refractory Metals and Hard Materials 94 (January 2021): 105373. http://dx.doi.org/10.1016/j.ijrmhm.2020.105373.

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26

Ramesh Babu, Shashank, Matias Jaskari, Antti Järvenpää, and David Porter. "The Effect of Hot-Mounting on the Microstructure of an As-Quenched Auto-Tempered Low-Carbon Martensitic Steel." Metals 9, no. 5 (May 11, 2019): 550. http://dx.doi.org/10.3390/met9050550.

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The effect of hot-mounting for metallographic studies of as-quenched low-carbon martensitic steels has been studied. Hot-mounting is typically carried out at 150–200 °C, i.e., a low-temperature tempering regime. Cold- and hot-mounted specimens from an as-quenched low-carbon auto-tempered steel were examined using a scanning electron microscope and their hardness levels were also compared. It was found that hot-mounting causes additional tempering that manifests as the appearance of new precipitates in those regions that are free of auto-tempered cementite. The observations were rationalized using DICTRA simulations to calculate the potential growth of cementite. Hot-mounting was also shown to cause a small but statistically significant increase in the hardness of the martensite.

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27

Yuan, Kang, Robert Eriksson, Ru Lin Peng, Xin Hai Li, Sten Johansson, and Yan Dong Wang. "Interdiffusion and Microstructure Simulation in Ni and Co Based Overlay Coatings on a Ni Based Superalloy at High Temperatures." Advanced Materials Research 922 (May 2014): 850–55. http://dx.doi.org/10.4028/www.scientific.net/amr.922.850.

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In turbine engines, Ni or Co based alloys are used at high temperature, either as base materials, superalloys, or deposited on the surface of superalloys, as coatings. In the present study, two different MCrAlY overlay coatings, Ni and Co based, on a Ni based superalloy IN792 were aged for different times in air at three temperatures, 900°C, 1000°C and 1100°C. The aging processes were simulated by using DICTRA software by focusing on the interdiffusion behavior in the superalloy-coating systems. The results of simulation captured the main microstructural features observed and were used to analyze the diffusion behavior of alloying elements and the corresponding microstructure development. It was found that coating composition and temperature affected significantly the microstructure near the superalloy-coating interface, and their relations were mapped as a summary.

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28

Sanhueza, J. P., D. Rojas, O. Prat, J. Garcia, R. Espinoza, C. Montalba, and M. F. Melendrez. "Precipitation kinetics in a 10.5%Cr heat resistant steel: Experimental results and simulation by TC-PRISMA/DICTRA." Materials Chemistry and Physics 200 (October 2017): 342–53. http://dx.doi.org/10.1016/j.matchemphys.2017.07.083.

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29

Garcia, José, and Orlando Prat. "Experimental investigations and DICTRA simulations on formation of diffusion-controlled fcc-rich surface layers on cemented carbides." Applied Surface Science 257, no. 21 (August 2011): 8894–900. http://dx.doi.org/10.1016/j.apsusc.2011.05.024.

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30

Li, J., T. Liu, W. Chen, S. Wang, L. Zhang, Y. Du, and H. Xu. "Interdiffusion coefficients and atomic mobilities in fcc Cu-Fe-Mn alloys." Journal of Mining and Metallurgy, Section B: Metallurgy 50, no. 2 (2014): 93–99. http://dx.doi.org/10.2298/jmmb140323018l.

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In the present work, the interdiffusion coefficients in fcc Cu-Fe-Mn alloys were experimentally determined via a combination of solid/solid diffusion couples, electron probe microanalysis (EPMA) technique and Matano-Kirkaldy method. Based on the reliable thermodynamic description of fcc phase in the Cu-Fe-Mn system available in the literature as well as the ternary diffusion coefficients measured in the present work, the atomic mobilities in fcc Cu-Fe-Mn alloys were assessed by utilizing the DICTRA (Diffusion Controlled TRAnsformation) software package. The calculated interdiffusion coefficients based on the assessed atomic mobilities agree well with most of the experimental data. The comprehensive comparison between various model-predicted diffusion properties and the measured data, including the concentration penetration profiles, interdiffusion flux profile, and diffusion paths, further verify the reliability of the presently obtained atomic mobilities.

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31

Tancret, F. "Thermo-Calc and Dictra simulation of constitutional liquation of gamma prime (γ′) during welding of Ni base superalloys." Computational Materials Science 41, no. 1 (November 2007): 13–19. http://dx.doi.org/10.1016/j.commatsci.2007.02.008.

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32

Rettig, Ralf, Astrid Heckl, and Robert F. Singer. "Modeling of Precipitation Kinetics of TCP-Phases in Single Crystal Nickel-Base Superalloys." Advanced Materials Research 278 (July 2011): 180–85. http://dx.doi.org/10.4028/www.scientific.net/amr.278.180.

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The precipitation of brittle so-called TCP-phases is critical for the application of Re-containing single crystal superalloys. In this work a fully multicomponent precipitation model is presented, which is capable of simulating the precipitation process of the TCP-phases in superalloys considering complex precipitation sequences with several metastable phases. The model is coupled to multicomponent thermodynamic CALPHAD calculations and relies on multicomponent diffusion models based on the TC-API interface of the software DICTRA. The required mobility database has been newly developed and covers all relevant alloying elements of the Ni-base superalloys including rhenium (Re) and ruthenium (Ru). It is well known that adding Ru strongly reduces TCP-phase precipitation. Based on the developed precipitation model, possible mechanisms are investigated to explain this effect and it is concluded that Ru mostly influences the nucleation rate by a combined influence on interface energy, “reverse partitioning” and γ’-phase fraction.

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33

Střílková, Lucie, Jan Holešinský, Anastasia Maslova, Zdeněk Kuboň, and Vlastimil Vodárek. "Microstructural Stability of P23/P91 Dissimilar Welds during Creep at 500°C." Materials Science Forum 782 (April 2014): 319–24. http://dx.doi.org/10.4028/www.scientific.net/msf.782.319.

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This paper deals with microstructural stability of P23/P91 dissimilar welds during long-term creep exposure at 500°C. Detailed TEM investigations on minor phase evolution were performed on specimens after long-term creep exposure. Microstructural changes in the decarburized layer of the P23 steel were studied using EBSD and TEM. Experimental data on minor phase evolution were compared to the results of thermodynamic (Thermocalc) and kinetic (Dictra) simulations. Evolution of minor phases in the P23/P91 welds during creep at 500°C was in a good agreement with results of microstructural modelling. Partial decarburization of the P23 occurred at the expense of dissolving M7C3 phase. Microstructure of the partly decarburized zone in the P23 steel remained bainitic in all specimens investigated. In spite of the partial decarburization in the P23 steel during longterm creep exposure at 500°C, creep failures occurred in the ICHAZ of the P23 steel.

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Zhang, Li Jun, Dan Dan Liu, Wei Bin Zhang, Shao Qing Wang, Ying Tang, Na Ta, Ming Wei, and Yong Du. "A New Diffusivity Database for Multi-Component Al Alloys: Focusing on Ternary Systems and its Effect on Microstructure Evolution during Solidification." Materials Science Forum 794-796 (June 2014): 611–16. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.611.

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A new atomic mobility database for Fcc_A1, L12, Bcc_A2, Bcc_B2, and liquid phases in the Al-Cu-Fe-Mg-Mn-Ni-Si-Zn system has been established via a hybrid approach of experiment, first-principles calculations and DICTRA (DIffusion Controlled TRAnsformation) software, focusing on the atomic mobility parameters in ternary systems. Various diffusivities can be computed as a function of temperature and composition. The reliability of this diffusivity database is further validated by comparing the calculated and measured diffusion properties in a series of ternary and quaternary diffusion couples, including concentration profiles, diffusion paths, interdiffusion fluxes, and so on. The effect of the diffusivity database on microstructure evolution during solidification is demonstrated by the phase field simulation of primary (Al) grains in Al356.1 alloy. The simulation results indicate that such accurate diffusivity database is highly needed for the quantitative simulation of microstructural evolution during solidification.

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35

Kolli, Javaheri, Kömi, and Porter. "On the Role of Grain Size and Carbon Content on the Sensitization and Desensitization Behavior of 301 Austenitic Stainless Steel." Metals 9, no. 11 (November 6, 2019): 1193. http://dx.doi.org/10.3390/met9111193.

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The effect of grain size in the range 72 to 190 μm and carbon content in the range 0.105–0.073 wt.% on the intergranular corrosion of the austenitic stainless steel 301 has been investigated. Grain boundary chromium depletion has been studied directly using energy dispersive X-ray spectroscopy combined with scanning transmission electron microscopy and indirectly using double loop electrochemical potentiokinetic reactivation tests. In addition, chromium depletion has been modelled using the CALPHAD Thermo-Calc software TC-DICTRA. It is shown that the degree of sensitization measured using the double loop electrochemical potentiokinetic reactivation tests can be successfully predicted with the aid of a depletion parameter based on the modelled chromium depletion profiles for heat treatment times covering both the sensitization and de-sensitization or self-healing. Additionally, along with intergranular M23C6 carbides, intragranular M23C6 and Cr2N nitrides that affect the available Cr for grain boundary carbide precipitation were also observed.

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36

Yang, Chao, Yong An Min, Hong Ping Sun, Tie Gu, and Jin Ming Fu. "Study of Identifying the Banded Structure of 8620 Steel Bars." Advanced Materials Research 915-916 (April 2014): 643–49. http://dx.doi.org/10.4028/www.scientific.net/amr.915-916.643.

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The level of ferrite/pearlite banding in gear steel can be affected significantly by cooling rates, however, different sizes own diverse bands in the same cooling rate. The lower-level degree banding was got under the faster cooling speed, whereas the higher-level degree banding under the slower cooling speed. The alloying elements segregation can be characterized in the fixed speed according to the banding. Banded segregation in a hot rolled SAE8620 gear steel was investigated by DIL805A dilatometer, OM, electron microprobe analysis(EPMA). The transformation temperature of rich solute and poor solute were calculated by JMatPro software. Meanwhile, the diffusion distance of carbon was also figured by DICTRA. Results showed that the difference of Ar3 temperatures for solute-depleted and solute-rich zones will impact the banded intensity, while the diffusion distance of carbon decrease with an increasingly of cooling rate, the banded structure relieved. The corresponding band adopted 0.2 °C/s cooling rate can characterize the first banded segregation of alloy elements.

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37

Zhang, Xianguang, Goro Miyamoto, Yuki Toji, and Tadashi Furuhara. "Effects of Heating Rate on Formation of Globular and Acicular Austenite during Reversion from Martensite." Metals 9, no. 2 (February 24, 2019): 266. http://dx.doi.org/10.3390/met9020266.

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The effects of heating rate on the formation of acicular and globular austenite during reversion from martensite in Fe–2Mn–1.5Si–0.3C alloy have been investigated. It was found that a low heating rate enhanced the formation of acicular austenite, while a high heating rate favored the formation of globular austenite. The growth of acicular γ was accompanied by the partitioning of Mn and Si, while the growth of globular γ was partitionless. DICTRA simulation revealed that there was a transition in growth mode from partitioning to partitionless for the globular austenite with an increase in temperature at high heating rate. High heating rates promoted a reversion that occurred at high temperatures, which made the partitionless growth of globular austenite occur more easily. On the other hand, the severer Mn enrichment into austenite at low heating rate caused Mn depletion in the martensite matrix, which decelerated the reversion kinetics in the later stage and suppressed the formation of globular austenite.

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38

Chen, Peng, Jian Fu, Jingkuan Yang, and Xiaowu Li. "A critical role of aluminium on austenite formation in high aluminium added steels." Metallurgical Research & Technology 117, no. 5 (2020): 502. http://dx.doi.org/10.1051/metal/2020047.

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Novel alloys with high aluminium addition have been developed recently for the new concepts of δ-TRIP, δ-QP and some other high-aluminium low-density steels. The aluminium addition dramatically affects the thermodynamics and kinetics of the formation of austenite. In the present study, the effect of aluminium on the initial microstructure of ferrite and pearlite has been investigated. The equilibrium prediction of phase fraction by thermodynamics calculations is in accordance with the measured austenite fraction during isothermal at intercritical temperature range; both results strongly demonstrate a significant influence of aluminium addition on intercritical region. The isothermal transformation of high aluminium steel during intercritical annealing was delayed, which has an instruction for process design of the industrial continuous annealing and galvanization. The austenite formation during heating in intercritical region was also obviously affected by aluminium addition. The transformation kinetics simulation conducted by DICTRA simulation, as well as the experimental results of dilatometry, indicate a delayed austenite transformation during heating process.

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39

Çelik, G. A., M. I. Tzini, Ş. Polat, J. Aristeidakis, Ş. H. Atapek, P. I. Sarafoglou, and G. N. Haidemenopoulos. "Simulation and analysis of the solidification characteristics of a Si-Mo ductile iron." Journal of Mining and Metallurgy, Section B: Metallurgy 57, no. 1 (2021): 53–62. http://dx.doi.org/10.2298/jmmb200717003c.

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High silicon and molybdenum ductile cast irons (Si-Mo alloys) are commonly used as exhaust manifold materials suffering from high temperature-oxidation and thermal-mechanical fatigue. The structural integrity of cast Si-Mo alloys under these service conditions is attributed to their microstructure consisting of spheroidal graphite and Mo-rich carbide embedded in a ferritic matrix. However, the cast structure includes also pearlite structure having a detrimental effect on the mechanical properties, therefore the cast matrix needs to be heat treated. In this study, the solidification of a Si-Mo ductile iron was investigated using (i) thermodynamic and kinetic calculations by Thermo-Calc and DICTRA software and (ii) thermal analysis in order to reveal out the sequence of phase formation and the phase transformations during solidification and (iii) microanalysis by energy dispersive spectrometer in order to determine elemental segregation and compare with the calculated values. The solidified structure was also characterized and all microstructural features were specified.

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Xiao, Xiang, Guoquan Liu, Benfu Hu, Jinsan Wang, and Wenbin Ma. "Coarsening behavior for M23C6 carbide in 12 %Cr-reduced activation ferrite/martensite steel: experimental study combined with DICTRA simulation." Journal of Materials Science 48, no. 16 (March 29, 2013): 5410–19. http://dx.doi.org/10.1007/s10853-013-7334-5.

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Prat, O., J. Garcia, D. Rojas, C. Carrasco, and G. Inden. "Investigations on the growth kinetics of Laves phase precipitates in 12% Cr creep-resistant steels: Experimental and DICTRA calculations." Acta Materialia 58, no. 18 (October 2010): 6142–53. http://dx.doi.org/10.1016/j.actamat.2010.07.033.

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Chen, H., and T. Barman. "Thermo-Calc and DICTRA modelling of the β-phase depletion behaviour in CoNiCrAlY coating alloys at different Al contents." Computational Materials Science 147 (May 2018): 103–14. http://dx.doi.org/10.1016/j.commatsci.2018.02.013.

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Tao, Su-Fen, Fu-Ming Wang, Gui-Lin Sun, Zhan-Bing Yang, and Chang-Rong Li. "DICTRA Simulation of Holding Time Dependence of NbC Size and Experimental Study of Effect of NbC on Austenite Grain Growth." Metallurgical and Materials Transactions A 46, no. 8 (May 8, 2015): 3670–78. http://dx.doi.org/10.1007/s11661-015-2922-4.

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Ojo, O. A., and F. Tancret. "Clarification on “Thermo-Calc and Dictra simulation of constitutional liquation of gamma prime (γ′) during welding of Ni-base superalloys”." Computational Materials Science 45, no. 2 (April 2009): 388–89. http://dx.doi.org/10.1016/j.commatsci.2008.10.014.

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Naseri, Larouche, Martinez, Breton, and Massinon. "Analytical Modeling of the Mixed-Mode Growth and Dissolution of Precipitates in a Finite System." Metals 9, no. 8 (August 14, 2019): 889. http://dx.doi.org/10.3390/met9080889.

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In this paper, a novel analytical modeling of the growth and dissolution of precipitates in substitutional alloys is presented. This model uses an existing solution for the shape-preserved growth of ellipsoidal precipitates in the mixed-mode regime, which takes into account the interfacial mobility of the precipitate. The dissolution model is developed by neglecting the transient term in the mass conservation equation, keeping the convective term. It is shown that such an approach yields the so-called reversed-growth approximation. A time discretization procedure is proposed to take into account the evolution of the solute concentration in the matrix as the phase transformation progresses. The model is applied to calculate the evolution of the radius of spherical -Al2Cu precipitates in an Al rich matrix at two different temperatures, for which growth or dissolution occurs. A comparison of the model is made, with the results obtained using the numerical solver DICTRA. The very good agreement obtained for cases where the interfacial mobility is very high indicates that the time discretization procedure is accurate.

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Jia, Tao, Run Ni, Hanle Wang, Jicheng Shen, and Zhaodong Wang. "Investigation on the Formation of Cr-Rich Precipitates at the Interphase Boundary in Type 430 Stainless Steel Based on Austenite–Ferrite Transformation Kinetics." Metals 9, no. 10 (September 26, 2019): 1045. http://dx.doi.org/10.3390/met9101045.

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The Cr-rich precipitates at the interphase boundary in stainless steels not only lead to the sensitization, which further induces the intergranular corrosion and intergranular stress corrosion cracking, but also significantly deteriorate the ductility and toughness. In this work, the formation of Cr-rich precipitates at the interphase boundary in type 430 stainless steel was investigated from the perspective of austenite–ferrite transformation kinetics. Cyclic heat treatment was firstly conducted to reveal the kinetic mode of transformation behavior, i.e., local equilibrium or para equilibrium. Subsequently, interrupted quenching during continuous cooling was carried out, which illustrated clearly the relevance of the formation of interphase Cr-rich precipitates to the Cr enrichment adjacent to the interphase boundary as revealed by line scanning of energy dispersive spectroscopy (EDS). Finally, this enrichment of Cr was interpreted by DICTRA simulation, which is based on the determined kinetic mode for austenite–ferrite transformation. This work has, for the first time, established the correlation between the formation of interphase Cr-rich precipitates and the austenite–ferrite transformation kinetics.

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Epishin, Alexander, Anton Chyrkin, Bettina Camin, Romain Saillard, Sophie Gouy, and Bernard Viguier. "Interdiffusion in CMSX-4 Related Ni-Base Alloy System at a Supersolvus Temperature." Defect and Diffusion Forum 407 (March 2021): 1–10. http://dx.doi.org/10.4028/www.scientific.net/ddf.407.1.

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Interdiffusion in Ni-base superalloy CMSX-4 and alloys related to CMSX-4 was investigated at the temperature 1288 °C, which is 8 °C above the γ’-solvus temperature of this superalloy, 1280 °C. This temperature is of a special interest because it is a temperature of hot isostatic pressing applied to CMSX-4 and modeling of this process needs verified diffusion data for this specific temperature. Various diffusion couples were assembled from the investigated alloys, annealed at 1288 °C and studied by electron probe microanalysis. So far as the annealing temperature was higher than the γ’-solvus temperature of CMSX-4 and other investigated alloys have no strengthening γ’-phase, interdiffusion occurred in the fcc solid solutions of nickel. It was found that in the case when the γ’-forming and γ-stabilizing elements diffuse in the same direction (towards nickel) the diffusion rate accelerates, but when they diffuse in the opposite directions (counter diffusion) it slows down. Such an interdiffusion behavior is in agreement with the results predicted with diffusion simulation software Dictra.

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Cliche, Nicolas, Sylvain Ringeval, Philippe Petit, Jacques Bellus, Eric Georges, François Cortial, Jean-Loup Heuzé, Anne-Françoise Gourgues-Lorenzon, and Vladimir A. Esin. "Thermokinetic Modelling of High-Temperature Evolution of Primary Nb(C,N) in Austenite Applied to Recrystallization of 316Nb Austenitic Stainless Steel." Metals 11, no. 5 (April 27, 2021): 715. http://dx.doi.org/10.3390/met11050715.

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The size evolution of niobium carbonitrides Nb(C,N) and the evolution of the composition of an austenitic matrix in 316Nb stainless steel were simulated using DICTRA software. For the first time, the complete nine-element composition of steel was taken into account during isothermal and even anisothermal heat treatments. A reduced model was then proposed to optimize the calculation time for complex heat treatments. The change in the mean Nb content in austenite due to Nb(C,N) evolution during different heat treatments was studied. It qualitatively agrees with experimental data as obtained by electron probe microanalysis. Furthermore, the model was successfully applied to explain the effect of heat treatments on the recrystallization behavior of 316Nb steel during hot torsion tests. Moreover, the effect of the thermodynamic database and the number of alloying elements chosen was discussed. We showed that taking into account seven or even nine elements greatly improves the accuracy compared to usual simplified compositions. The proposed method can be useful in designing heat treatments promoting or conversely hindering recrystallization for a wide variety of Nb-bearing steels.

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Bai, Weimin, Guanglong Xu, Mingyue Tan, Zhijie Yang, Lijun Zeng, Di Wu, Libin Liu, and Ligang Zhang. "Diffusivities and Atomic Mobilities in bcc Ti-Mo-Zr Alloys." Materials 11, no. 10 (October 8, 2018): 1909. http://dx.doi.org/10.3390/ma11101909.

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β-type (with bcc structure) titanium alloys have been widely used as artificial implants in the medical field due to their favorable properties. Among them, Ti-Mo alloy attracted numerous interests as metallic biomaterials. Understanding of kinetic characteristics of Ti alloys is critical to understand and manipulate the phase transformation and microstructure evolution during homogenization and precipitation. In this work, diffusion couple technique was employed to investigate the diffusion behaviors in bcc Ti-Mo-Zr alloys. The diffusion couples were prepared and annealed at 1373 K for 72 h and 1473 K for 48 h, respectively. The composition-distance profiles were obtained via electron probe micro-analysis (EPMA). The chemical diffusion coefficients and impurity diffusion coefficients were extracted via the Whittle-Green method and Hall method. The obtained diffusion coefficients were assessed to develop a self-consistent atomic mobility database of bcc phase in Ti-Mo-Zr system. The calculated diffusion coefficients were compared with the experimental results. They showed good agreement. Simulations were implemented by Dictra Module in Thermo-Calc software. The predicted composition-distance profiles, inter-diffusion flux, and diffusion paths are consistent with experimental data, confirming the accuracy of the database.

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Papaefthymiou, Spyros, Marianthi Bouzouni, and Roumen H. Petrov. "Study of Carbide Dissolution and Austenite Formation during Ultra–Fast Heating in Medium Carbon Chromium Molybdenum Steel." Metals 8, no. 8 (August 16, 2018): 646. http://dx.doi.org/10.3390/met8080646.

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In this study, UltraFast Heat Treatment (UFHT) was applied to a soft annealed medium carbon chromium molybdenum steel. The specimens were rapidly heated and subsequently quenched in a dilatometer. The resulting microstructure consists of chromium-enriched cementite and chromium carbides (in sizes between 5–500 nm) within fine (nano-sized) martensitic and bainitic laths. The dissolution of carbides in austenite (γ) during ferrite to austenite phase transformation in conditions of rapid heating were simulated with DICTRA. The results indicate that fine (5 nm) and coarse (200 nm) carbides dissolve only partially, even at peak (austenitization) temperature. Alloying elements, especially chromium (Cr), segregate at austenite/carbide interfaces, retarding the dissolution of carbides and subsequently austenite formation. The sluggish movement of the austenite /carbide interface towards austenite during carbide dissolution was attributed to the partitioning of Cr nearby the interface. Moreover, the undissolved carbides prevent austenite grain growth at peak temperature, resulting in a fine-grained microstructure. Finally, the simulation results suggest that ultrafast heating creates conditions that lead to chemical heterogeneity in austenite and may lead to an extremely refined microstructure consisting of martensite and bainite laths and partially dissolved carbides during quenching.

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Journal articles on the topic 'DICTRA'

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