Criteria for the dilatometric analysis to determine the transformation kinetics during continuous heating

Vázquez–Gómez, Octavio; Gallegos-Pérez, A. I.; López–Martínez, Edgar; Vergara–Hernández, Héctor Javier; Barrera-Godínez, José Antonio

doi:10.1007/s10973-018-7449-7

Cited by 16 publications

(18 citation statements)

References 46 publications

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“…Generally, the structure of the industrial polycrystalline samples is uniform, and the dilatation is homogeneous and pronounced during phase transformation, so the thermal dilatation method is often used to measure the phase transformation behavior of alloys with diffusion transformation. [ 19–23 ] However, for shear‐type martensitic transformation, the thermal dilatation method is not effective, because shear transformation has strong directionality, and the volume does not obviously change with temperature, and the dilatational amount measured from different directions varies greatly. [ 24,25 ] Currently, the influence of grain size on diffusion transformation and the columnar‐grained phase transformation behavior on the transformation temperature has been seldom reported.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Initial Columnar‐Grained Inhomogeneity of Electrical Steels on the Transformation Temperature

Yang

et al. 2021

steel research int.

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The effects of various initial structures and heating and cooling rates on the columnar‐grained transformation temperature are studied by a thermal dilatometer and electron backscatter diffraction. The results show that deformation can reduce the thermal hysteresis more effectively than decrease the heating rate, and the phase transformation hysteresis of the deformed sample is the smallest during heating, followed by the columnar‐grained sample with a slow heating rate, whereas the columnar‐grained sample with a fast heating rate has the largest phase transformation hysteresis. Moreover, the dilatational amount changes greatly with cooling rate. The coarse columnar grains can severely restrain dilatation. The smaller dilatational amount is related to the incomplete phase transformation of the columnar grains and also related to the suppression of the dilatational amount of the small grains by the surrounding columnar grains. In contrast, the largest dilatational amount is caused by the relatively sufficient phase transformation. In addition, the changes of the transformation temperature and the dilatational amount are mainly induced by the grain size effect and the inhomogeneity of the structures, but {100} texture can affect the uniformity of grain size.

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Section: Introductionmentioning

confidence: 99%

Effect of the Initial Columnar‐Grained Inhomogeneity of Electrical Steels on the Transformation Temperature

Yang

et al. 2021

steel research int.

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“…Austenite formation in low carbon steels may occur in two stages: 6,8,9,12,13,23,24) firstly, by the decomposition of pearlite and secondly by the transformation of ferrite. These stages can be seen in the derivative curve (Fig.…”

Section: Dilatometrymentioning

confidence: 99%

“…The austenite formation kinetics for each stage and microstructural condition was analyzed through the kinetic parameters associated with the nucleation and growth mechanisms using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. Despite the fact that the model describes the transformation degree under isothermal conditions, it has been used to evaluate the non-isothermal kinetic parameters and obtain an interpretation of the transformation mechanisms 24,25,28) through the nucleation rate laws proposed by Cahn. 29) Here, the transformation degree was adjusted using the JMAK nonlinear model: Here, X γ is the volume fraction of austenite, t is the transformation time, and k and n are the kinetic parameters associated with the nucleation and growth mechanisms.…”

Section: Austenite Formation Kineticsmentioning

confidence: 99%

Effect of Cold-rolling and Heating Rate on Austenite Formation in a Low–Carbon Steel

et al. 2022

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“…In this sense, it has been shown that austenite formation occurs mainly by nucleation and growth processes through studies where kinetic parameters associated with transformation mechanisms in low carbon steels have been empirically determined [1][2][3]. However, there are studies on other types of steels such as: medium and high carbon [4][5][6], microalloyed steels [7,8], cast irons [9][10][11] and alloys with certain quantity of alloying elements such as silicon, manganese and chromium [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, the study related to the formation of austenite has been extended to the use of kinetic models to determine the degree of transformation under isothermal and continuous conditions [1][2][3][5][6][7][8][9][10][11]14,16,17]. The implementation of kinetics models depends mainly on the approach; i.e., analytical kinetic models based on the Johnson-Mehl-Avrami (JMA) model aim to describe the coupled transformation mechanisms (nucleation, growth and impingement) under specific kinetic conditions [16,17], while conventional models try to estimate the transformation degree through the change in dilation strain with respect to the phases present by lattice parameters as a function of temperature and composition [3,6,18].…”

Section: Introductionmentioning

confidence: 99%

Application of a Non-Isothermal Numerical-Analytical Model to Determine the Kinetics of Austenite Formation in a Silicon Alloyed Steel

et al. 2022

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A non-isothermal transformation model was proposed to determine the austenite formation kinetics in a steel alloyed with 2.6% wt. Si by dilatometric analysis, considering that the nucleation mechanism does not change with the heating rate. From the dilatometric analysis, it was observed that the austenite formation occurs in two stages; critical temperatures, degree and austenite formation rate were determined. The activation energies associated with each of the stages were obtained employing the Kissinger method (226.67 and 198.37 kJ mol−1 for the first and second stage) which was used in concert with the austenite formation rate in the non-isothermal model as a first approximation, with acceptable results in the second stage, but not in the first due to the activation energies magnitude. Then, the activation energies were adjusted by minimizing the minimal squares error between estimated and experimental austenite formation degree, obtaining values of 158.50 kJ mol−1 for the first and 165.50 kJ mol−1 for the second stage. These values are consistent with those reported for the diffusion of carbon in austenite-FCC in silicon steels. With these activation energies it was possible to predict the austenite formation degree with a better level of convergence when implementing the non-isothermal model.

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Criteria for the dilatometric analysis to determine the transformation kinetics during continuous heating

Cited by 16 publications

References 46 publications

Effect of the Initial Columnar‐Grained Inhomogeneity of Electrical Steels on the Transformation Temperature

Effect of the Initial Columnar‐Grained Inhomogeneity of Electrical Steels on the Transformation Temperature

Effect of Cold-rolling and Heating Rate on Austenite Formation in a Low–Carbon Steel

Application of a Non-Isothermal Numerical-Analytical Model to Determine the Kinetics of Austenite Formation in a Silicon Alloyed Steel

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