A one-parameter approach to determining the critical conditions for the initiation of dynamic recrystallization

Poliak, Evgueni I.; Jonas, John J.

doi:10.1016/1359-6454(95)00146-7

Cited by 873 publications

(488 citation statements)

References 26 publications

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“…The critical stresses for initiation of DRX (σ C ) were obtained from the inflection points in the work hardening rate (θ=dσ/dε) versus flow stress (σ) curves (before the peak stress) or from the minimums in the -dθ/dσ versus σ curves [16,17]. The former plots were used to determine other characteristic stresses.…”

Section: Work Hardening Rate Analysismentioning

confidence: 99%

Hot deformation behavior, dynamic recrystallization, and physically-based constitutive modeling of plain carbon steels

Saadatkia

Mirzadeh

Cabrera

2015

Materials Science and Engineering: A

148

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The high-temperature deformation behaviors of low and medium carbon steels with respectively 0.06 and 0.5 wt.% C were investigated under strain rate and temperature ranges of 10 -4 -10 -1 s -1 and of 900-1100 °C. Three types of dynamic recrystallization (DRX) flow behaviors were identified, namely single peak, multiple transient steady state, and cyclic behaviors. The normalized critical stress (and strain) for the low and medium carbon steels were about 0.846 (0.531) and 0.879 (0.537), respectively. For both steels, the apparent deformation activation energy and the power of the hyperbolic sine law were found to be near the lattice self-diffusion activation energy of austenite (270 kJ/mol) and 4.5, respectively. As a result, it was concluded that the flow stress of plain carbon steels during hot deformation is mainly controlled by dislocation climb, and based on physically-based constitutive analysis, it was found that carbon has a slight effect on the hot flow stress of plain carbon steels. The significance of the approach used in this work was shown to be its reliance on the theoretical analysis based on the deformation mechanisms, which makes the comparison more reliable.

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Section: Work Hardening Rate Analysismentioning

confidence: 99%

Hot deformation behavior, dynamic recrystallization, and physically-based constitutive modeling of plain carbon steels

Saadatkia

Mirzadeh

Cabrera

2015

Materials Science and Engineering: A

148

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“…Under low temperatures and high strain rates, namely, high Z conditions, the peak of the DRX curve may become very broad, which makes it similar to the dynamic recovery only curves. Under this situation, a plot of the derivative of the stress to strain vs. stress can be used to reveal the subtle DRX peak, [29] as shown in Figure 2(b). The peak stress can be identified as 204.1 MPa when the derivative is equal to 0; thus, the peak strain can be identified as strain 2 of 0.56.…”

Section: A Deformation Processmentioning

confidence: 99%

Effect of Austenite Deformation on the Microstructure Evolution and Grain Refinement Under Accelerated Cooling Conditions

Zhao

Palmiere

2017

Metall and Mat Trans A

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Although there has been much research regarding the effect of austenite deformation on accelerated cooled microstructures in microalloyed steels, there is still a lack of accurate data on boundary densities and effective grain sizes. Previous results observed from optical micrographs are not accurate enough, because, for displacive transformation products, a substantial part of the boundaries have disorientation angles below 15 deg. Therefore, in this research, a niobium microalloyed steel was used and electron backscattering diffraction mappings were performed on all of the transformed microstructures to obtain accurate results on boundary densities and grain refinement. It was found that with strain rising from 0 to 0.5, a transition from bainitic ferrite to acicular ferrite occurs and the effective grain size reduces from 5.7 to 3.1 lm. When further increasing strain from 0.5 to 0.7, dynamic recrystallization was triggered and postdynamic softening occurred during the accelerated cooling, leading to an inhomogeneous and coarse transformed microstructure. In the entire strain range, the density changes of boundaries with different disorientation angles are distinct, due to different boundary formation mechanisms. Finally, the controversial influence of austenite deformation on effective grain size of low-temperature transformation products was argued to be related to the differences in transformation conditions and final microstructures.

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“…While the classical nucleation theories consider energy as key factor for the onset of dynamic recrystallization [17][18][19][20] a different approach from [21] introduces a minimum amount of work necessary. By identifying the stored deformation energy as work the authors of [22][23][24] also incorporate the idea of a relaxation as dissipation part and relate nucleation to the rate of hardening. When an external applied work ߪ ߝ̇ exceeds the internal entropy production, ܲ ௗ , another process within the microstructure has to take place which supposed to be the nucleation of new grains with the condition:…”

Section: Dynamic Recrystallizationmentioning

confidence: 99%

Modelling of flow behaviour and dynamic recrystallization during hot deformation of MS-W 1200 using the phase field framework

et al. 2016

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Abstract.A new simulation environment is developed to simulate the evolution of microstructure and the corresponding flow stress during rolling. An orientation dependent crystal plasticity hardening model is coupled to grain evolution-, recovery-and recrystallization kinetics within a phase field framework. Hardening and softening kinetics are treated consecutive to differentiate between individual effects. Simulation results are compared to hot compression tests at 1373 K with a strain rate of 1 s -1 .

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A one-parameter approach to determining the critical conditions for the initiation of dynamic recrystallization

Cited by 873 publications

References 26 publications

Hot deformation behavior, dynamic recrystallization, and physically-based constitutive modeling of plain carbon steels

Hot deformation behavior, dynamic recrystallization, and physically-based constitutive modeling of plain carbon steels

Effect of Austenite Deformation on the Microstructure Evolution and Grain Refinement Under Accelerated Cooling Conditions

Modelling of flow behaviour and dynamic recrystallization during hot deformation of MS-W 1200 using the phase field framework

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