Dynamic and post-dynamic recrystallization under hot, cold and severe plastic deformation conditions

Sakai, Taku; Belyakov, Andrey; Kaibyshev, Rustam; Miura, Hiromi; Jonas, John J.

doi:10.1016/j.pmatsci.2013.09.002

Cited by 2,120 publications

(1,000 citation statements)

References 223 publications

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“…6b the OIM analysis. The microstructure consists of elongated grains, and some of these are surrounded by small grains in a growing process, characterizing the necklace mechanism, which is typical of dynamic recrystallization [22,23] indicating that, under the analyzed condition, dynamic recrystallization took place. The data displayed in Fig.…”

Section: Microstructural Evolutionmentioning

confidence: 99%

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Silva

Gallego

Cabrera

et al. 2015

Materials Science and Engineering: A

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In this work, we studied the influence of the interpass time (20 and 5 s) on the interaction between recrystallization and strain-induced precipitation occurring during multiple passes' deformations under continuous cooling conditions in a high niobium-and nitrogen-bearing austenitic stainless steel (ISO 5832-9). The correlation between microstructure evolution and hot mechanical properties was performed by physical simulation using hot torsion tests. The microstructure evolution was analyzed by optical microscopy, transmission electron microscopy and electron back scattered diffraction (EBSD). This technique indicated that dynamic recrystallization occurred at the first passes promoting an excellent grain refinement. On the other hand, shorter interpass time (5 s) allowed higher volume fraction of smallest precipitates than larger interpass time (20 s). After soaking, only TiNbN precipitates were found, whereas, Z-phase (CrNbN) and NbN were formed during thermomechanical processing. Particles with sizes between 20 and 50 nm were effective to pin grain boundaries and dislocations.2

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Section: Microstructural Evolutionmentioning

confidence: 99%

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Silva

Gallego

Cabrera

et al. 2015

Materials Science and Engineering: A

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“…This behaviour can also be explained with dynamic-softening processes, which can be accompanied by the grain coarsening under certain conditions. 14,15 The changes in the grain size could be caused by a proper combination of a sufficiently high amplitude and an adequate loading time (i.e., a higher number of cycles). It is possible that a slight increase in the grain size at 220 MPa was caused simply by a high stress amplitude, which allowed the grain coarsening to partially develop even during 24.000 cycles.…”

Section: Discussionmentioning

confidence: 99%

Microstructural changes of ECAP-processed magnesium alloy AZ91 during cyclic loading at different stress-amplitude levels

Štěpánek¹,

Pantělejev²,

Man³

et al. 2018

Mater. Tehnol.

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Microstructural changes of magnesium alloy AZ91 after fatigue loading in the EX-ECAP state were evaluated using EBSD. It was found that both the number fraction of low-angle boundaries and parameter KAM decreased after the testing at a stress amplitude of 160 MPa but started to increase with the increasing stress amplitude. This behaviour can be explained with a mutual influence of dislocation accumulation (which is stronger with a higher stress amplitude) and dynamic softening (which is weaker with a decreasing number of cycles/cycles to failure). The average grain size remained almost unchanged except at a stress amplitude of 180 MPa, which could have been caused by certain conditions allowing an ideal development of both mentioned phenomena. Keywords: magnesium alloy, ECAP, EBSD, fatigue loading V pri~ujo~em~lanku avtorji opisujejo ovrednotenje mikrostrukturnih sprememb magnezijeve zlitine AZ91 z EBSD metodo zaradi utrujanja po procesiranju z ECAP-postopkom. Ugotovili so, da se tako dele`malo kotnih mej kot tudi parameter razlik v kristalografski orientaciji kristalnih zrn (KAM; angl.: Kernel Average Misorientation) zni`ujeta po testiranju pri napetostni amplitudi toda pri~neta nara{~ati z nara{~ajo~o napetostno amplitudo. To obna{anje si je mo~razlo`iti z isto~asnim vplivom kopi~enja dislokacij, (ki je intenzivnej{e pri vi{jih napetostnih amplitudah) in dinami~nim meh~anjem, (ki je manj{e pri manj{em razmerju med dejanskim {tevilom ciklov in {tevilom ciklov do poru{itve). Povpre~na velikost kristalnih zrn je ostala skoraj nespremenjena pri napetostni amplitudi 180 MPa, kar je lahko posledica specifi~nih pogojev, ki omogo~ajo idealen potek obeh omenjeni pojavov (mehanizmov). Klju~ne besede: zlitina na osnovi magnezija, ekstremno mo~na plasti~na deformacija (SPD) dose`ena z enokanalnim pravokotnim procesiranjem (ECAP), preiskovalna metoda na osnovi uklona povratno sipanih elektronov (EBSD), utrujanje oz. dinami~no (cikli~no) obremenjevanje

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“…The recrystallization nucleation will occur when a critical activation energy is achieved. At the second stage, DRX and dynamic recovery (DRV) occur and increase, and the increasing rate of flow stress decelerates until a maximum stress where the thermal softening on account of DRX and DRV are balanced with WH 34,35 34,35 . The existing literatures indicate that there are close relationships among flow stress, strain, strain rate and temperature.…”

Section: Acquisition Of Experimental Stress-strain Datamentioning

confidence: 99%

Numerical Description of Hot Flow Behaviors at Ti-6Al-2Zr-1Mo-1V Alloy By GA-SVR and Relative Applications

et al. 2016

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Hot compression tests of as-cast Ti-6Al-2Zr-1Mo-1V alloy in a wide temperature range of 1073-1323 K and strain rate range of 0.01-10 s-1 were conducted by a servo-hydraulic and computer-controlled Gleeble-1500 machine. The hot flow behaviors of Ti-6Al-2Zr-1Mo-1V alloy show highly non-linear relationships with strain, strain rate and temperature. In order to accurately and effectively characterize the complex flow behaviors, support vector regression (SVR) which is a machine learning method was combined with Genetic Algorithm (GA) to characterize the flow behaviors, namely, the GA-SVR. The study abilities, generation abilities, and modeling efficiencies of the improved Arrhenius-type constitutive model, ANN, and GA-SVR for flow behaviors of as-cast Ti-6Al-2Zr-1Mo-1V alloy were detailedly compared. Comparison results show that the study ability of the GA-SVR is as strong as the ANN. The generation abilities and modeling efficiencies of these models were shown as follows in ascending order: the improved Arrhenius-type constitutive model < ANN < GA-SVR. Based on the established GA-SVR, the continuously three-dimensional relationships among flow stress, temperature, strain, and strain rate were constructed, which improve the simulation accuracy and related research fields where stress-strain data play important roles.

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Dynamic and post-dynamic recrystallization under hot, cold and severe plastic deformation conditions

Cited by 2,120 publications

References 223 publications

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Microstructural changes of ECAP-processed magnesium alloy AZ91 during cyclic loading at different stress-amplitude levels

Numerical Description of Hot Flow Behaviors at Ti-6Al-2Zr-1Mo-1V Alloy By GA-SVR and Relative Applications

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