Effects of Austenitization Temperature and Pre-Deformation on CCT Diagrams of 23MnNiCrMo5-3 Steel

The combined effect of deformation temperature and strain value on the continuous cooling transformation (CCT) diagram of low-alloy steel with 0.23% C, 1.17% Mn, 0.79% Ni, 0.44% Cr, and 0.22% Mo was studied. The deformation temperature (identical to the austenitization temperature) was in the range suitable for the wire rolling mill. The applied compressive deformation corresponded to the true strain values in an unusually wide range. Based on the dilatometric tests and metallographic analyses, a total of five different CCT diagrams were constructed. Pre-deformation corresponding to the true strain of 0.35 or even 1.0 had no clear effect on the austenite decomposition kinetics at the austenitization temperature of 880 °C. During the long-lasting cooling, recrystallization and probably coarsening of the new austenitic grains occurred, which almost eliminated the influence of pre-deformation on the temperatures of the diffusion-controlled phase transformations. Decreasing the deformation temperature to 830 °C led to the significant acceleration of the austenite → ferrite and austenite → pearlite transformations due to the applied strain of 1.0 only in the region of the cooling rate between 3 and 35 °C·s−1. The kinetics of the bainitic or martensitic transformation remained practically unaffected by the pre-deformation. The acceleration of the diffusion-controlled phase transformations resulted from the formation of an austenitic microstructure with a mean grain size of about 4 µm. As the analysis of the stress–strain curves showed, the grain refinement was carried out by dynamic and metadynamic recrystallization. At low cooling rates, the effect of plastic deformation on the kinetics of phase transformations was indistinct.

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The Phase Transformations in Hypoeutectoid Steels Mn-Cr-Ni

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0080 ◽

2015 ◽

Vol 60 (1) ◽

pp. 497-502 ◽

Cited By ~ 2

Author(s):

E. RoŻniata ◽

R. Dziurka

Keyword(s):

Chemical Composition ◽

Phase Transformations ◽

Critical Points ◽

Light Microscope ◽

Cooling Curves ◽

Critical Temperatures ◽

Martensitic Microstructure ◽

Cct Diagrams ◽

Kinetics Of ◽

Undercooled Austenite

Abstract The results of a microstructure and hardness investigations of the hypoeutectoid steels Mn-Cr-Ni, imitating by its chemical composition toughening steels, are presented in the paper. The analysis of the kinetics of phase transformations of undercooled austenite of steels containing different amounts of alloying elements in their chemical composition, constitutes the aim of investigations. Metallographic examinations were carried out on a Axiovert 200 MAT light microscope. Sections were etched with a 3% HNO3 solution in C2H5OH. Dilatometric tests were performed using L78 R.I.T.A dilatometer. Using dilatometer the changes of elongation (Δl) of the samples with dimensions Ø 3×10 mm as a function of temperature (T) were registered. Obtained heating curves were used to precisely determine the critical temperatures (critical points) for the tested steels, while the differentiation of obtained cooling curves allowed to precisely define the temperatures of the beginning and the end of particular transition to draw CCT diagrams. Four CCT diagrams worked out for the tested hypoeutectoid steels (for quenching of steel) are - in the majority of steels - separated by the undercooled austenitic range and are of the letter „C” shape. However, for steels with Mn and Ni the separation of diffusive transformations from the bainitic transformation by the stable austenitic range is not observed. Hardenability of four investigated hypoeutectoid steels is similar, but still not high. To obtain martensite in the microstructure of these steels, it is necessary to apply the cooling rate higher than 25°C/s. The exception constitutes the Mn - Ni steel, in which only cooling with the rate higher than 50°C/s allows to achieve the martensitic microstructure and to avoid diffusive transformations (pearlitic and ferritic).

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Kinetic Simulations of Diffusion-Controlled Phase Transformations in Cu-Based Alloys

Diffusion Foundations ◽

10.4028/www.scientific.net/df.15.1 ◽

2018 ◽

Vol 15 ◽

pp. 1-22 ◽

Cited By ~ 3

Author(s):

Ying Tang ◽

Qing Chen ◽

Anders Engström

Keyword(s):

Phase Transformations ◽

Computer Aided Design ◽

Copper Alloys ◽

Liquid Solution ◽

Calphad Approach ◽

Diffusion Controlled ◽

Mobility Database ◽

Thermo Calc Software ◽

Aided Design ◽

Kinetics Of

In this chapter, we present computational kinetics of diffusion-controlled phase transformations in Cu-based alloys, which becomes possible only most recently due to the establishment of the first atomic mobility database (MOBCU) for copper alloys. This database consists of 29 elements including most common ones for industrial copper alloys. It contains descriptions for both the liquid and Fcc_A1 phases. The database was developed through a hybrid CALPHAD approach based on experiments, first-principles calculations, and empirical rules. We demonstrate that by coupling the created mobility database with the existing compatible thermodynamic database (TCCU), all kinds of diffusivities in both solid and liquid solution phases in Cu-based alloys can be readily calculated. Furthermore, we have applied the combination of MOBCU and TCCU to simulate diffusion-controlled phenomena, such as solidification, nucleation, growth, and coarsening of precipitates by using the kinetic modules (DICTRA and TC-PRISMA) in the Thermo-Calc software package. Many examples of simulations for different alloys are shown and compared with experimental observations. The remarkable agreements between calculation and experimental results suggest that the atomic mobilities for Cu-based alloys have been satisfactorily described. This newly developed mobility database is expected to be continuously improved and extended in future and will provide fundamental kinetic data for computer-aided design of copper base alloys.

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Modeling of the Free Radical Copolymerization Kinetics of n-Butyl Acrylate, Methyl Methacrylate and 2-Ethylhexyl Acrylate Using PREDICI®

Processes ◽

10.3390/pr7070395 ◽

2019 ◽

Vol 7 (7) ◽

pp. 395 ◽

Cited By ~ 1

Author(s):

Javier A. Gómez-Reguera ◽

Eduardo Vivaldo-Lima ◽

Vida A. Gabriel ◽

Marc A. Dubé

Keyword(s):

Free Radical ◽

Methyl Methacrylate ◽

Butyl Acrylate ◽

Radical Copolymerization ◽

Free Radical Copolymerization ◽

Diffusion Controlled ◽

Wide Range ◽

Kinetics Of ◽

Global Parameters ◽

Copolymerization Kinetics

Kinetic modeling of the bulk free radical copolymerizations of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (EHA); methyl methacrylate (MMA) and EHA; as well as BA, MMA and EHA was performed using the software PREDICI®. Predicted results of conversion versus time, composition versus conversion, and molecular weight development are compared against experimental data at different feed compositions. Diffusion-controlled effects and backbiting for BA were incorporated into the model as they proved to be significant in these polymerizations. The set of estimated global parameters allows one to assess the performance of these copolymerization systems over a wide range of monomer compositions.

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Phase Transformations and Microstructure of the Alloyed Steels for Mining Application

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.410.215 ◽

2021 ◽

Vol 410 ◽

pp. 215-220

Author(s):

Mikhail V. Maisuradze ◽

Maxim A. Ryzhkov ◽

Arkadiy Yu. Zhilyakov

Keyword(s):

Chemical Composition ◽

Ambient Temperature ◽

Phase Transformations ◽

Rock Drilling ◽

Austenitization Temperature ◽

Hardened Steels ◽

Continuous Cooling ◽

Drilling Equipment ◽

Cct Diagrams

The dilatometer study of the austenite transformations in steels with different chemical composition was conducted. The studied steels were classified as the air hardened steels of different alloying systems (Cr-Ni-Mo, Cr-Mn-Si-Mo and Cr-Mo-V) designed for the mining applications (rock drilling equipment, drilling instrument). The microstructure of the steels was investigated after continuous cooling at the rates of 0.1...30 °C/s from the austenitization temperature down to the ambient temperature. The CCT diagrams of the studied steels were plotted showing that the alloying with different set of elements can provide the desired hardenability and microstructure.

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Scintigraphic studies in rats. Kinetics of insulin analogues covering wide range of receptor affinities

Diabetes ◽

10.2337/diabetes.40.5.628 ◽

1991 ◽

Vol 40 (5) ◽

pp. 628-632 ◽

Cited By ~ 3

Author(s):

I. Jensen ◽

V. Kruse ◽

U. D. Larsen

Keyword(s):

Insulin Analogues ◽

Wide Range ◽

Kinetics Of

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Kinetics of acetylthiocholine binding to electric eel acetylcholinesterase in glycerol/water solvents of increased viscosity Evidence for a diffusion-controlled reaction

Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology ◽

10.1016/0167-4838(82)90131-5 ◽

1982 ◽

Vol 704 (1) ◽

pp. 52-58 ◽

Cited By ~ 47

Author(s):

Brian B. Hasinoff

Keyword(s):

Glycerol Water ◽

Diffusion Controlled ◽

Electric Eel ◽

Kinetics Of ◽

Diffusion Controlled Reaction

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Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽

10.3390/polym13111686 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1686

Author(s):

Andrey Galukhin ◽

Roman Nosov ◽

Ilya Nikolaev ◽

Elena Melnikova ◽

Daut Islamov ◽

...

Keyword(s):

Kinetic Analysis ◽

Single Step ◽

Polymerization Kinetics ◽

Scanning Calorimetry ◽

Modulated Differential Scanning Calorimetry ◽

Diffusion Controlled ◽

Polymerization Product ◽

The One ◽

Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

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Combining experimental and simulation data of molecular processes via augmented Markov models

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1704803114 ◽

2017 ◽

Vol 114 (31) ◽

pp. 8265-8270 ◽

Cited By ~ 53

Author(s):

Simon Olsson ◽

Hao Wu ◽

Fabian Paul ◽

Cecilia Clementi ◽

Frank Noé

Keyword(s):

Force Field ◽

Structural Changes ◽

Markov Models ◽

Force Fields ◽

Divide And Conquer ◽

Simulation Data ◽

Wide Range ◽

Simulation And Experiment ◽

Kinetics Of

Accurate mechanistic description of structural changes in biomolecules is an increasingly important topic in structural and chemical biology. Markov models have emerged as a powerful way to approximate the molecular kinetics of large biomolecules while keeping full structural resolution in a divide-and-conquer fashion. However, the accuracy of these models is limited by that of the force fields used to generate the underlying molecular dynamics (MD) simulation data. Whereas the quality of classical MD force fields has improved significantly in recent years, remaining errors in the Boltzmann weights are still on the order of a few kT, which may lead to significant discrepancies when comparing to experimentally measured rates or state populations. Here we take the view that simulations using a sufficiently good force-field sample conformations that are valid but have inaccurate weights, yet these weights may be made accurate by incorporating experimental data a posteriori. To do so, we propose augmented Markov models (AMMs), an approach that combines concepts from probability theory and information theory to consistently treat systematic force-field error and statistical errors in simulation and experiment. Our results demonstrate that AMMs can reconcile conflicting results for protein mechanisms obtained by different force fields and correct for a wide range of stationary and dynamical observables even when only equilibrium measurements are incorporated into the estimation process. This approach constitutes a unique avenue to combine experiment and computation into integrative models of biomolecular structure and dynamics.

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