A discontinuous dynamic recrystallization model incorporating characteristics of initial microstructure

Zhong, Xiting; Li-jiang, Huang; Wang, Lei; Liu, Feng; Dong, Xiao-ming; Zhang, Zhonghua

doi:10.1016/s1003-6326(18)64874-5

Cited by 9 publications

(2 citation statements)

References 49 publications

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“…In recent years, significant efforts have been made by various research groups to develop constitutive models that accurately describe the flow behavior of metals and alloys [9][10][11][12][13]. These models play a crucial role in predicting and understanding the microstructure evolution during hot deformation, particularly in the case of low alloyed steels.…”

Section: Introductionmentioning

confidence: 99%

Modeling the hot deformation behavior of micro-alloyed steel in the single and two-phase fields

Sharifi,

Buzolin,

Bakhtiari

et al. 2023

J. Phys.: Conf. Ser.

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Continuous casting is a well-established process to produce steel slabs. However, the surfaces of the slabs may crack during processing. The occurrence of cracks is related to different phenomena, i.e., ferrite formation, presence of precipitates, and microstructural modifications during manufacturing processing. In the present work, we developed a physically based mesoscale model to describe the plastic deformation of micro-alloyed steel in the single and two-phase fields, as well as the microstructure evolution. We implemented a dislocation density-based constitutive model to calculate the strain hardening and the stress softening produced by dynamic recovery using the Kocks-Mecking (KM) formalism for the austenite and ferrite. We coupled the KM model with the Johnson-Mehl-Avrami-Kolmogorov model to consider the dynamic recrystallization of the austenitic phase. The nucleation and growth of the recrystallized grains, driven by the stored energy, compete with the annihilation of dislocations due to dynamic recovery. In the two-phase domain, the iso-work condition for the load partition is implemented. We calculated the ferrite volume fraction by fitting the data obtained using JmatPro software. Moreover, an Arrhenius-type equation correlates the yield stress to the Zener-Hollomon parameter. We validated the model with isothermal uniaxial compression tests of microalloyed steel over the temperature range of 650 °C-1100 °C and strain rates of 10−2 s−1 and 10−3 s−1 using a Gleeble® 3800 thermomechanical simulator.

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Section: Introductionmentioning

confidence: 99%

Modeling the hot deformation behavior of micro-alloyed steel in the single and two-phase fields

Sharifi,

Buzolin,

Bakhtiari

et al. 2023

J. Phys.: Conf. Ser.

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“…Considerable investigations have been done on DRX kinetics, and those research studies concentrate on revealing the relationships between the deformation conditions and the microstructures by analyzing the true strain-stress curves obtained from hot compression tests. Recrystallization models were constructed based on the hot compression tests with wide temperature and strain rate ranges to predict DRX evolution [5][6][7][8]. For a more accurate dynamic recrystallization model, it was of great importance to obtain the critical conditions for DRX, which was usually identified by using the θ − σ and (dθ/dσ) − σ curves [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Evolution of Dynamic Recrystallization in 5CrNiMoV Steel during Hot Forming

Wang

2020

Advances in Materials Science and Engineering

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The dynamic recrystallization (DRX) behavior of 5CrNiMoV steel was investigated through hot compression at temperatures of 830–1230°C and strain rates of 0.001–10 s−1. From the experimental results, most true stress-strain curves showed the typical nature of DRX that a single peak was reached at low strains followed by a decrease of stress and a steady state finally at relatively high strains. The constitutive behavior of 5CrNiMoV steel was analyzed to deduce the operative deformation mechanisms, and the correlation between flow stress, temperature, and strain rate was expressed as a sine hyperbolic type constitutive equation. Based on the study of characteristic stresses and strains on the true stress-strain curves, a DRX kinetics model was constructed to characterize the influence of true strain, temperature, and strain rate on DRX evolution, which revealed that higher temperatures and lower strain rates had a favorable influence on improving the DRX volume fraction at the same true strain. Microstructure observations indicated that DRX was the main mechanism and austenite grains could be greatly refined by reducing the temperature of hot deformation or increasing the strain rate when complete recrystallization occurred. Furthermore, a DRX grain size model of 5CrNiMoV was obtained to predict the average DRX grain size during hot forming.

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Discontinuous Dynamic Recrystallization Mechanism and Twinning Evolution during Hot Deformation of Incoloy 825

Zhong

Li-jiang

Liu

2020

J. of Materi Eng and Perform

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Discontinuous dynamic recrystallization (DDRX), which involves multiple nucleation and grain growth processes, plays a crucial role in grain refinement; however, the underlying mechanism and the significant role of twin boundaries (TBs) remain poorly understood. Here, the evolution of characteristic microstructures and the fraction and density of TBs under different deformation conditions (i.e., 1050-1200°C, 0.001-1 s 21 ) in Incoloy 825 was investigated through a thermomechanical simulator, electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM). The first strand of recrystallized grains nucleated along the original grain boundaries (GBs), separated by the newly formed random high-angle grain boundaries (HAGBs), which were transformed from low-angle grain boundaries (LAGBs) and pre-existing TBs. Subsequently, straight TBs forming in the new grains increased the misorientation angle, promoting the migration of stagnated grain boundaries, and parts of newly generated twinning chains at the front of the recrystallization zone converted into random HAGBs, providing sites for the following layer of nucleation. Moreover, triple junctions between the recrystallized and deformed grains also served as potential nucleation sites when the LAGBs in the large misorientation gradient were transformed into random HAGBs. Quantitative relationships between the recrystallized grain size and TB density were obtained.

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A discontinuous dynamic recrystallization model incorporating characteristics of initial microstructure

Cited by 9 publications

References 49 publications

Modeling the hot deformation behavior of micro-alloyed steel in the single and two-phase fields

Modeling the hot deformation behavior of micro-alloyed steel in the single and two-phase fields

Evolution of Dynamic Recrystallization in 5CrNiMoV Steel during Hot Forming

Discontinuous Dynamic Recrystallization Mechanism and Twinning Evolution during Hot Deformation of Incoloy 825

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