A continuous dynamic recrystallization model to describe the hot deformation behaviour of a Ti5553 alloy

Sub-solvus dynamic recrystallization (DRX) mechanisms in an advanced γ-γ’ nickel-based superalloy GH4151 were investigated by isothermal compression experiments at 1040 °C with a strain rate of 0.1 s−1 and various true strain of 0.1, 0.3, 0.5, and 0.7, respectively. This has not been reported in literature before. The electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) technology were used for the observation of microstructure evolution and the confirmation of DRX mechanisms. The results indicate that a new dynamic recrystallization mechanism occurs during hot deformation of the hot-extruded GH4151 alloy. The nucleation mechanism can be described as such a feature, that is a primary γ’ (Ni3(Al, Ti, Nb)) precipitate embedded in a recrystallized grain existed the same crystallographic orientation, which is defined as heteroepitaxial dynamic recrystallization (HDRX). Meanwhile, the conventional DRX mechanisms, such as the discontinuous dynamic recrystallization (DDRX) characterized by bulging grain boundary and continuous dynamic recrystallization (CDRX) operated through progressive sub-grain merging and rotation, also take place during the hot deformation of the hot-extruded GH4151 alloy. In addition, the step-shaped structures can be observed at grain boundaries, which ensure the low-energy surface state during the DRX process.

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Effect of Initial Grain Size on Deformation Behavior and Dynamic Recrystallization of Magnesium Alloy AZ31

Materials Science Forum ◽

10.4028/www.scientific.net/msf.488-489.223 ◽

2005 ◽

Vol 488-489 ◽

pp. 223-226 ◽

Cited By ~ 21

Author(s):

Xu Yue Yang ◽

Masayoshi Sanada ◽

Hiromi Miura ◽

Taku Sakai

Keyword(s):

Magnesium Alloy ◽

Dynamic Recrystallization ◽

Grain Refinement ◽

Hot Deformation ◽

Structural Changes ◽

Kink Bands ◽

Alloy Az31 ◽

Continuous Dynamic Recrystallization ◽

Magnesium Alloy Az31 ◽

Continuous Dynamic

Hot deformation and associated structural changes were studied in compression of a magnesium alloy AZ31 with initial grain sizes (D0) of 22 µm and 90 µm at a temperature of 573K. D0 influences significantly the flow curve and the kinetics of grain refinement during hot deformation. For D0 = 22 µm, grain fragmentation takes place due to frequent formation of kink bands initially at corrugated grain boundaries and then in grain interiors in low strain, followed by full development of new fine grains in high strain. For D0 = 90 µm, in contrast, twinning takes place in coarser original grains, and then kink bands and new fine grains are formed mainly in finer ones at low strains. Then new grains are formed in necklace along the boundaries of coarse original grains, followed by their development into the grain interiors. Grain refinement in the Mg alloy can be concluded to result from a series of deformation-induced continuous reactions, they are essentially similar to continuous dynamic recrystallization (cDRX).

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Modified kinetic model for describing continuous dynamic recrystallization behavior of Al 2219 alloy during hot deformation process

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2019.153301 ◽

2020 ◽

Vol 817 ◽

pp. 153301 ◽

Cited By ~ 8

Author(s):

Lei Liu ◽

Yunxin Wu ◽

Hai Gong ◽

Fang Dong ◽

A.S. Ahmad

Keyword(s):

Kinetic Model ◽

Dynamic Recrystallization ◽

Hot Deformation ◽

Deformation Process ◽

Recrystallization Behavior ◽

Continuous Dynamic Recrystallization ◽

Dynamic Recrystallization Behavior ◽

Continuous Dynamic

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Review on Dynamic Recrystallization of Martensitic Stainless Steels during Hot Deformation: Part I—Experimental Study

Metals ◽

10.3390/met11040572 ◽

2021 ◽

Vol 11 (4) ◽

pp. 572

Author(s):

Hamed Aghajani Derazkola ◽

Eduardo García Gil ◽

Alberto Murillo-Marrodán ◽

Damien Méresse

Keyword(s):

Dynamic Recrystallization ◽

Stainless Steels ◽

Hot Deformation ◽

Large Strains ◽

Microstructural Changes ◽

Ultrafine Grains ◽

Microstructure Changes ◽

Continuous Dynamic Recrystallization ◽

Martensitic Stainless Steels ◽

Continuous Dynamic

The evolution of the microstructure changes during hot deformation of high-chromium content of stainless steels (martensitic stainless steels) is reviewed. The microstructural changes taking place under high-temperature conditions and the associated mechanical behaviors are presented. During the continuous dynamic recrystallization (cDRX), the new grains nucleate and growth in materials with high stacking fault energies (SFE). On the other hand, new ultrafine grains could be produced in stainless steel material irrespective of the SFE employing high deformation and temperatures. The gradual transformation results from the dislocation of sub-boundaries created at low strains into ultrafine grains with high angle boundaries at large strains. There is limited information about flow stress and monitoring microstructure changes during the hot forming of martensitic stainless steels. For this reason, continuous dynamic recrystallization (cDRX) is still not entirely understood for these types of metals. Recent studies of the deformation behavior of martensitic stainless steels under thermomechanical conditions investigated the relationship between the microstructural changes and mechanical properties. In this review, grain formation under thermomechanical conditions and dynamic recrystallization behavior of this type of steel during the deformation phase is discussed.

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Effect of Niobium and Titanium on the Dynamic Recrystallization during Hot Deformation of Stabilized Ferritic Stainless Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.1229 ◽

2004 ◽

Vol 467-470 ◽

pp. 1229-1236 ◽

Cited By ~ 3

Author(s):

Tarcisio R. Oliveira ◽

Frank Montheillet

Keyword(s):

Dynamic Recrystallization ◽

Stainless Steels ◽

Hot Deformation ◽

Boundary Migration ◽

Solute Drag ◽

Shear Direction ◽

Ferritic Stainless Steels ◽

Solid Solution Strengthening ◽

Continuous Dynamic Recrystallization ◽

Continuous Dynamic

The study was carried out to understand the mechanisms occurring during dynamic recrystallization of hot deformed 11% chromium stabilized ferritic stainless steels and to compare the behaviour induced by various types of stabilization. It was observed that continuous dynamic recrystallization (CDRX) operates in all materials starting at the onset of straining. Niobium has a more pronounced influence on hardening than titanium during hot deformation, which is due to solid solution strengthening and also to the reduction or stopping of grain boundary migration by solute drag effect. The D2 component, { 2 1 1 }<111>, was found as the major texture component at the steady state for the torsion tests carried along the negative shear direction. It was likely to be formed by the combination of straining and growth of the grains exhibiting both low stored energy and low rotation rate of the crystallographic axes.

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A Physically Based Constitutive Model and Continuous Dynamic Recrystallization Behavior Analysis of 2219 Aluminum Alloy during Hot Deformation Process

Materials ◽

10.3390/ma11081443 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1443 ◽

Cited By ~ 15

Author(s):

Lei Liu ◽

Yunxin Wu ◽

Hai Gong ◽

Shuang Li ◽

A. S. Ahmad

Keyword(s):

Constitutive Model ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

Flow Behavior ◽

Large Strains ◽

Al Alloy ◽

Continuous Dynamic Recrystallization ◽

Physically Based ◽

Continuous Dynamic

The isothermal compression tests of the 2219 Al alloy were conducted at the temperature and the strain rate ranges of 623–773 K and 0.01–10 s−1, respectively, and the deformed microstructures were observed. The flow curves of the 2219 Al alloy obtained show that flow stress decreases with the increase in temperature and/or the decrease in strain rate. The physically based constitutive model is applied to describe the flow behavior during hot deformation. In this model, Young’s modulus and lattice diffusion coefficient are temperature-dependent, and the creep exponent is regarded as a variable. The predicted values calculated by the constitutive model are in good agreement with the experimental results. In addition, it is confirmed that the main softening mechanism of the 2219 Al alloy during hot deformation is dynamic recovery and incomplete continuous dynamic recrystallization (CDRX) by the analysis of electron backscattered diffraction (EBSD) micrographs. Moreover, CDRX can readily occur under the condition of high temperatures, low strain rates, and large strains. Meanwhile, the recrystallization grain size will also be larger.

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A Comparative Study on the Hot Deformation Behavior of As-Cast and Twin-Roll Cast Mg-6.8Y-2.5Zn-0.4Zr Alloy

Materials ◽

10.3390/ma14133628 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3628

Author(s):

Kristina Kittner ◽

Madlen Ullmann ◽

Ulrich Prahl

Keyword(s):

Dynamic Recrystallization ◽

Hot Deformation ◽

Deformation Behavior ◽

Hot Deformation Behavior ◽

Cast Material ◽

Continuous Dynamic Recrystallization ◽

Roll Casting ◽

Continuous Dynamic ◽

Twin Roll Cast ◽

Twin Roll

The Mg-6.8Y-2.5Zn-0.4Zr (WZ73) alloy exhibits different microstructure characteristic after conventional casting compared to the twin-roll cast (TRC) state. Twin-roll casting results in a finer microstructure, where the LPSO phases are more finely distributed and less strongly connected. A transfer of the hot deformation behavior from the as-cast condition to the TRC condition is only possible to a limited extent due to the microstructural differences. Both states show differences in the recrystallization behavior during hot deformation. In the conventional cast state, dynamic recrystallization (DRX) is assumed to be delayed by the occurrence of coarse blocky LPSO phases. Main DRX mechanisms are continuous dynamic recrystallization (CDRX), particle stimulated nucleation (PSN) and twin induced dynamic recrystallization (TDRX). The deformed TRC sample showed pronounced DRX at almost all deformation conditions. Besides the TDRX and the PSN mechanism, kink induced dynamic recrystallization (KDRX) can be observed. Optimum deformation conditions for both states are temperatures from 500 °C to 520 °C, and strain rates ranging from 0.01 s−1 to 0.1 s−1 for the as-cast material as well as a strain rate of 1 s−1 for the TRC material.

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Investigation into Microstructure Evolution of Co–Ni–Cr–W–Based Superalloy During Hot Deformation

Frontiers in Materials ◽

10.3389/fmats.2021.684985 ◽

2021 ◽

Vol 8 ◽

Author(s):

Wei Zhang ◽

Baohong Zhu ◽

Shuaishuai Wu ◽

Shutian Tao

Keyword(s):

Dynamic Recrystallization ◽

Microstructure Evolution ◽

Hot Deformation ◽

Electron Backscatter Diffraction ◽

Strain Rates ◽

Compression Tests ◽

Continuous Dynamic Recrystallization ◽

Nucleation Mechanisms ◽

Ebsd Technique ◽

Continuous Dynamic

Hot compression tests were conducted using a Gleeble 3500 thermomechanical simulator at temperatures ranging from 1,000 to 1,200°C with the strain rate ranging from 0.1 to 10 s−1. Electron backscatter diffraction (EBSD) technique was employed by investigating the microstructure evolution during hot deformation. Microstructure observations reveal that deformation temperatures and strain rates have a significant effect on the DRX process. It is found that the fraction and grain size of DRX increase with the decreasing deformation temperature, along with the increasing high-angle grain boundaries (HAGBs). The fraction of DRX first decreases and then increases with the increase of strain rates. It is noted that there are both the nucleation mechanisms of discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) during the DRX process for Co–Ni–Cr–W–based superalloys. DDRX and CDRX are the primary and subsidiary nucleation mechanisms of DRX, respectively. It is also found that deformation temperatures and strain rates have almost no effect on the primary and subsidiary nucleation mechanisms of DRX. At the temperature above 1,150°C, the complete DRX occurred with the average grain sizes of about 25.32–29.01 μm. The homogeneity and refinement of microstructure can be obtained by selecting the suitable hot deformation parameters.

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Hot Deformation and Dynamic Recrystallisation Behaviour of Twin-Roll Cast Mg-6.8Y-2.5Zn-0.4Zr Magnesium Alloy

Materials ◽

10.3390/ma14020307 ◽

2021 ◽

Vol 14 (2) ◽

pp. 307

Author(s):

Madlen Ullmann ◽

Kristina Kittner ◽

Ulrich Prahl

Keyword(s):

Dynamic Recrystallization ◽

Power Dissipation ◽

Hot Deformation ◽

Deformation Behaviour ◽

Rate Sensitivity ◽

Cast Material ◽

Continuous Dynamic Recrystallization ◽

Forming Temperature ◽

Twin Roll Cast ◽

Twin Roll

In this work, the deformation behaviour of a twin-roll cast (TRC) Mg-6.8Y-2.5Zn-0.4Zr alloy during plane strain compression was characterised by high-temperature testing. Based on the experimental data, the values of strain-rate sensitivity, the efficiency of power dissipation and the instability parameter were investigated under the conditions of various hot deformation parameters. In contrast to conventionally cast material, no lamellae of the LPSO (long period stacking ordered) phase were precipitated in the magnesium matrix after TRC. The precipitation of fine lamellar LPSO phases only occurred during cooling to forming temperature after the heat treatment. Dynamic recrystallization (DRX) hardly occurred during deformation at temperatures between 350 °C and 400 °C. This can be attributed to the precipitation of the lamellar LSPO phases, which contribute to retardation of the DRX process. At higher deformation temperatures and strain rates DRX is pronounced and the twin-induced (TRDX) as well as continuous dynamic recrystallization could be identified as the dominant softening mechanisms. The processing maps were established by superimposing the instability map over the power dissipation map, this being associated with microstructural evolution analysis in the hot deformation processes. Two instability zones could be recognised for the twin-roll cast and heat-treated Mg-6.8Y-2.5Zn-0.4Zr alloy: (1) 350 °C to 460 °C and 0.01 s−1 to 0.3 s−1 and (2) 485 °C to 525 °C and 2.5 s−1 to 10 s−1, where deformation is not favourable.

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