Hot Deformation and Dynamic Recrystallization Behavior of Fe-8Mn-6Al-0.2C Steel

Hot deformation and dynamic recrystallization (DRX) behaviors of Fe-8Mn-6Al-0.2C steel were investigated by means of single-pass compression experiments at temperature ranging from 850 °C to 1150 °C and different strain rate of 0.01~10 s-1. The flow strain curves were analysed and showed that the higher temperature and lower strain rate led to the smaller critical stress, which meant softening mechanism was easier to occur; The constitutive equation of experimental steel was established and the relationship between peak strain and Z parameter was figured out; A hot processing map of experimental steel was developed over a power dissipation map for the typical strain of 0.9, indicating the best region of high workability in the study conditions. DRX was promoted with increase of deformation temperature and decrease of strain rate, and the banded grains had been broken and grew up obviously.

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Hot Deformation and Dynamic Recrystallization Behavior of CoCrNi and (CoCrNi)94Ti3Al3 Medium Entropy Alloys

Metals ◽

10.3390/met10101341 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1341

Author(s):

Hai-long Yi ◽

Daixiu Wei ◽

Yingchen Wang ◽

Liqiang Wang ◽

Ming-yang Fang ◽

...

Keyword(s):

Dynamic Recrystallization ◽

Hot Deformation ◽

Single Phase ◽

Thermomechanical Processing ◽

Grain Structure ◽

Solid Solution Hardening ◽

Recrystallization Behavior ◽

Lower Strain ◽

Dynamic Recrystallization Behavior ◽

Higher Temperature

The CoCrNi and precipitate-hardened (CoCrNi)94Ti3Al3 medium entropy alloys (MEAs) have attracted much attention, due to their exceptional mechanical properties, whereas the hot deformation characteristics have not been revealed. In the present study, we investigated the dynamic recrystallization behavior and microstructure evolutions of the two MEAs hot-compressed at single-phase temperatures. The constitutive equation was obtained, and microstructures were observed. Discontinuous dynamic recrystallization acted as a key mechanism of grain refinement at a relatively higher temperature and lower strain rate, which leads to the formation of a homogeneous grain structure. The addition of Ti and Al promoted dynamic recrystallization due to the solid solution hardening effect. The results provide valuable guidelines for microstructure refinement via thermomechanical processing.

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Flow Behavior and Dynamic Recrystallization of BT25y Titanium Alloy During Hot Deformation

High Temperature Materials and Processes ◽

10.1515/htmp-2016-0100 ◽

2018 ◽

Vol 37 (2) ◽

pp. 181-192 ◽

Cited By ~ 1

Author(s):

Xuemei Yang ◽

Hongzhen Guo ◽

Zekun Yao ◽

Shichong Yuan

Keyword(s):

Dynamic Recrystallization ◽

Hot Deformation ◽

Volume Fraction ◽

Flow Behavior ◽

Strain Rates ◽

Recrystallization Behavior ◽

Lower Strain ◽

Deformation Activation Energy ◽

Strain Data ◽

Dynamic Recrystallization Behavior

AbstractThe high-temperature plastic deformation and dynamic recrystallization behavior of BT25y alloy were investigated within the deformation temperatures of 1,213–1,293 K and strain rates of 0.001–1.0 s–1 on a Gleeble-1500 thermo-mechanical simulator. Results showed that the dynamic recrystallization (DRX) mechanism played an important role in the hot deformation of BT25y alloy. Based on the regression analysis of the true stress–strain data, the stress exponent and deformation activation energy of BT25y alloy were calculated to be 3.4912 and 288.0435 kJ/mol, respectively. The θ-σ and dθ/dσ–σ curves were plotted to further obtain the critical stress and critical strain for the occurrence of DRX. Based on the analysis results, the DRX kinetic model was established. The model was validated by the comparison between predicted and experimental volume fraction of DRX. As the DRX evolution was sensitive to deformation temperature and strain rate, quantities of dynamically recrystallized grains appeared at higher temperatures and lower strain rates.

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Characterization of Hot Deformation Behavior and Processing Maps of Mg-3Sn-2Al-1Zn-5Li Magnesium Alloy

Metals ◽

10.3390/met9121262 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1262 ◽

Cited By ~ 4

Author(s):

Yuhang Guo ◽

Yaodong Xuanyuan ◽

Chunnan Lia ◽

Sen Yang

Keyword(s):

Magnesium Alloy ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

Processing Maps ◽

Compression Tests ◽

Softening Mechanism ◽

Signal Peak ◽

The Operating Mechanism ◽

The Stability

The dynamic microstructure evolution of Mg-3Sn-2Al-1Zn-5Li magnesium alloy during hot deformation is studied by hot compression tests over the temperature range of 200–350 °C under the strain rate of 0.001–1 s−1, whereafter constitutive equations and processing maps are developed and constructed. In most of cases, the material shows typical dynamic recrystallization (DRX) features, with a signal peak value followed by a gradual decrease. The value of Q (deformation activation energy) is 138.89414 kJ/mol, and the instability domains occur at high strain rate but the stability domains are opposite, and the optimum hot working parameter for the studied alloy is determined to be 350 °C/0.001 s−1 according to the processing maps. Within 200–350 °C, the operating mechanism of dynamic recrystallization (DRX) of Mg-3Sn-2Al-1Zn-5Li alloy during hot deformation is mainly affected by strain rate. Dynamic recrystallization (DRX) structures are observed from the samples at 300 °C/0.001 s−1 and 350 °C/0.001 s−1, which consist of continuous DRX (CDRX) and discontinuous DRX (DDRX). However, dynamic recovery (DRV) still dominates the softening mechanism. At the grain boundaries, mass dislocation pile-ups and dislocation tangle provide sites for potential nucleation. Meanwhile, flow localization bands are observed from the samples at 200 °C/1 s−1 and 250 °C/0.1 s−1 as the main instability mechanism.

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The Influence of Chemical Composition on the Kinetics of Dynamic Recrystallization of IF Austenite

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.1193 ◽

2004 ◽

Vol 467-470 ◽

pp. 1193-1198

Author(s):

Roney Eduardo Lino ◽

Ronaldo Barbosa

Keyword(s):

Activation Energy ◽

Chemical Composition ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Apparent Activation Energy ◽

Hot Deformation ◽

Empirical Expression ◽

Softening Mechanism ◽

Points Of View ◽

Kinetics Of

Dynamic recrystallization, DRX, has become an increasingly important softening mechanism both from fundamental and industrial points of view. During finishing rolling of strips or wire rods, strain is accumulated from pass to pass so that DRX can be triggered. The time need for 50% of material to recrystallize, t50DRX, is strongly dependent on temperature and to a lesser extent on strain rate at which deformation occurs. Few studies report results on the kinetics of DRX and how this softening mechanism can be predicted for a given set of hot deformation conditions, namely strain, strain rate and pass temperature. The purpose of this paper was to investigate how the chemical composition of IF austenite can affect the kinetics of DRX by measuring the apparent activation energy for DRX, QDRX, for alloys with additions of Ti and a combination of Ti-Nb contents. Predicted and measured values of t50DRX, were compared and an empirical expression was proposed to model measured values.

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Hot Deformation Behavior of TC21 Alloy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.446-447.117 ◽

2013 ◽

Vol 446-447 ◽

pp. 117-121

Author(s):

Hai Lin Xu ◽

Hong Bo Dong ◽

Yong Wang

Keyword(s):

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

Deformation Temperature ◽

Dynamic Recovery ◽

Recrystallization Behavior ◽

Hot Deformation Behavior ◽

Dynamic Recrystallization Behavior ◽

Set Up ◽

Gleeble 3500

The dynamic recrystallization behavior of TC21 alloy during hot compression deformation was investigated at 870~990 °C and strain rate of 0.001~10 s-1 on a Gleeble-3500 thermo-simulation machine. The results show that dynamic recovery and dynamic recrystallization occurs during hot deformation. As the deformation temperature increases and strain rate decreases, the softening caused by dynamic recrystallization is more obvious. According to the relevance of flow stress, strain rate and deformation temperature, the dynamic recrystallization activation energy is obtained. The constitutive equation and dynamic recrystallization kinetics motel are set up through analyzing and calculating the data of thermo-simulation.

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HOT COMPRESSION DEFORMATION BEHAVIOR AND CONSTITUTIVE ANALYSIS OF EXTRUDED MAGNESIUM-BISMUTH ALLOYS

European Journal of Materials Science and Engineering ◽

10.36868/ejmse.2021.06.03.121 ◽

2021 ◽

Vol 6 (3) ◽

pp. 121-130

Author(s):

Guoyuan XIONG ◽

Lihua LIU ◽

Shuping HOU ◽

Weimin ZHAO ◽

Hui YU ◽

...

Keyword(s):

Dynamic Recrystallization ◽

Strain Rate ◽

Peak Stress ◽

Test Machine ◽

Isothermal Compression ◽

Simulation Test ◽

Stress Variation ◽

Softening Mechanism ◽

Constitutive Analysis ◽

Higher Temperature

The isothermal compression experiments of Mg-2Bi alloys were carried out under different temperature and strain rate by Gleeble 3500D thermal simulation test machine. The rheological stress variation law of the Mg-2Bi alloy was analysed under 200-350oC and 0.001-1.0 s-1. The results present that the peak stress enhances and the dynamic recrystallization grain size reduces with the decline of deformation temperature and the improvement of strain rate during isothermal compression of the Mg-2Bi alloy. In addition, the activation energy for alloy deformation is 130.03 kJ/mol. The softening mechanism of the Mg-2Bi alloy is mainly twin and dynamic recrystallization under a low temperature (200oC) condition. While at a higher temperature of 350oC, the softening mechanism changes to single dynamic recrystallization.

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Study on Flow Stress Characteristics of AZ31B under Multi-Stage Hot Deformation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.310.117 ◽

2013 ◽

Vol 310 ◽

pp. 117-123

Author(s):

Xin Tong Wu ◽

Zhao Yang Jin ◽

Juan Liu ◽

Xin Huang

Keyword(s):

Flow Stress ◽

Magnesium Alloy ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

Temperature Jump ◽

Peak Strain ◽

Stored Energy ◽

Deformation Degree ◽

Multi Stage

In order to improve the understanding of the rheological behavior of magnesium alloy AZ31B under multi-stage hot deformation, a series of isothermal compressing experiments with height reduction of 60% were performed at the temperatures of 250°C, 300°C, 350°C and 400°C and the strain rates of 0.01 s−1and 0.1 s−1 on a Gleeble 1500 thermo-mechanical simulator. The effects of temperature (jump), strain rate (jump), deformation degree and deformation interval time on the flow stress characteristics are investigated and discussed. It is shown that in the dual-stage deformation process with temperature jump or strain rate jump, values of peak stress and peak strain at the second-stage are lower than those at single-stage. The reason for this change is due to the deformation stored energy still retained in the material after its release during the first-stage deformation and deformation interval, such as dynamic recrystallization, meta-dynamic recrystallization, static recovery and static recrystallization The deformation resistance of the multi-stage deformation of AZ31B can be reduced by increasing the deformation degree at the first-stage or the deformation interval because it leads to adequate release of deformation stored energy, which improves the plastic formability of magnesium alloy.

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CONSTITUTIVE MODELING OF DYNAMIC RECRYSTALLIZATION AND PRECIPITATION BEHAVIOR OF Nb AND Ti OF Q1030 HIGH STRENGTH STEEL

Materials and Corrosion Engineering Management ◽

10.26480/macem.01.2020.01.05 ◽

2020 ◽

Vol 1 (1) ◽

pp. 01-05

Author(s):

J.J. Wang ◽

Y.L. Kang ◽

Y.L. Liu ◽

H Yu

Keyword(s):

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

High Strength Steel ◽

Critical Strain ◽

High Strength ◽

Second Phase ◽

Peak Strain ◽

Precipitation Behavior ◽

Deformation Equation

The thermal deformation and precipitation behavior at 900-1100℃ and strain rate of 0.1-5s-1 were studied by Gleeble-3800 thermal simulator of Q1030 high strength steel. The activation energy of hot deformation in austenite region was determined by regression method, and the hot deformation equation of the Q1030 high strength steel was established. The critical strain and peak strain of dynamic recrystallization were predicted accurately by fitting the inflection point with cubic polynomial of curve of Q1030 high strength steel, and relationship between critical strain and Z parameter was established. Finally, the precipitation behavior of Nb and Ti particles during low strain rate deformation was studied, the results show that the precipitated phases in steel are rectangular TiN, quadratic (Nb, Ti) (C, N) carbonitride, elliptical (Nb, Ti) C carbide and NbC. Thermodynamic calculation shows that the order of precipitation of the second phase in steel is TiN, TiC, NbC and NbN.

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