Dynamic Recrystallization Critical Conditions and a Physically–Based Constitutive Model of Al–4.8Mg Alloy Under Hot Working Conditions

The microstructure evolution and the mechanical behavior of Al–4.8Mg alloy were investigated by means of isothermal compression tests at various temperatures (280–520 °C) and strain rates (0.01–10 s−1). The results shown that there are three main mechanisms of dynamic softening of samples within the range of selected process parameters: dynamic recovery, dynamic recovery + dynamic recrystallization, and dynamic recrystallization, and the equiaxed dynamic recrystallization grain tends to be formed under higher temperature and higher strain rate. In order to accurately describe the dynamic recrystallization condition of Al-4.8Mg alloy under a wide range of hot deformation parameters, an improved dynamic recrystallization critical conditions model is proposed based on deformation activation energy and work-hardening rate. Additionally, a two–stage physically constitutive model considering the influence of work hardening–dynamic recovery and dynamic recrystallization is established. Comparisons between the predicted and experimental data indicate that the proposed model can adequately predict the flow stress in the range of selected process parameters with the average absolute relative error of 4.02%.

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A Characterization for the Hot Flow Behaviors of As-extruded 7050 Aluminum Alloy

High Temperature Materials and Processes ◽

10.1515/htmp-2014-0108 ◽

2015 ◽

Vol 34 (7) ◽

pp. 643-650

Author(s):

Guo-zheng Quan ◽

Jin Liu ◽

An Mao ◽

Bo Liu ◽

Jin-sheng Zhang

Keyword(s):

Aluminum Alloy ◽

Constitutive Model ◽

Work Hardening ◽

True Strain ◽

Deep Understanding ◽

Type Model ◽

Compression Tests ◽

Average Absolute Relative Error ◽

7050 Aluminum Alloy ◽

Peak Value

Abstract The deep understanding of flow behaviors of as-extruded 7050 aluminum alloy significantly contributes to the accuracy simulation for its various plastic forming processes. In order to obtain the improved Arrhenius-type equation with variable parameters for this alloy, a series of compression tests were performed at temperatures of 573 K, 623 K, 673 K, 723 K and strain rates of 0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1 with a height reduction of 60% on Gleeble-1500 thermo-mechanical simulator. It is obvious that strain rate, strain and temperature all have a significant effect on the hot flow behaviors, and the true stress–true strain curves indicate three types after the peak value: decreasing gradually to a steady state with sustaining DRX softening till a balance with work hardening, decreasing continuously with sustaining increasing DRX softening beyond work hardening and maintaining higher stress level after the peak value with a balance between work hardening and DRV softening. Based on the experimental data, the improved Arrhenius-type constitutive model was established to predict the high temperature flow stress of as-extruded 7050 aluminum alloy. The accuracy and reliability of the improved Arrhenius-type model were further evaluated in terms of the correlation coefficient (R), here 0.98428, the average absolute relative error (AARE), here 3.5%. The results indicate that the improved Arrhenius-type constitutive model presents a good predictable ability.

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A Comparative Study on Johnson–Cook, Modified Johnson–Cook, Modified Zerilli–Armstrong and Arrhenius-Type Constitutive Models to Predict Hot Deformation Behavior of TA2

High Temperature Materials and Processes ◽

10.1515/htmp-2019-0026 ◽

2019 ◽

Vol 38 (2019) ◽

pp. 699-714 ◽

Cited By ~ 2

Author(s):

Bing Zhang ◽

Xiaodi Shang ◽

Su Yao ◽

Qiuyu Wang ◽

Zhijuan Zhang ◽

...

Keyword(s):

Deformation Behavior ◽

Flow Behavior ◽

True Strain ◽

Constitutive Models ◽

Type Model ◽

Compression Tests ◽

Absolute Relative Error ◽

Average Absolute Relative Error ◽

Wide Range ◽

Jc Model

AbstractThe true strain data and true stress data are obtained from the isothermal compression tests under a wide range of strain rates (0.1–20 s−1) and temperatures (933–1,133 K) over the Gleeble-3500 thermomechanical simulator. The data are employed to generate the constitutive equations according to four constitutive models, respectively, the strain-compensated Arrhenius-type model, the modified Zerilli–Armstrong (ZA) model, the modified Johnson–Cook (JC) model and the JC model. In the meanwhile, a comparative research was made over the capacities of these four models and hence to represent the elevated temperature flow behavior of TA2. Besides, a comparison of the accuracy of the predictions of average absolute relative error, correlation coefficient (R) and the deformation behavior was made to test the sustainability level of these four models. It is shown from these results that the JC model is not suitable for the description of flow behavior of TA2 alloy in α+β phase domain, while the predicted values of modified JC model, modified ZA model and the strain-compensated Arrhenius-type model could be consistent well with the experimental values except under some deformation conditions. Moreover, the strain-compensated Arrhenius-type model can be also used to track the deformation behavior more precisely in comparison with other models.

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Physics-Based Constitutive Model to Predict Dynamic Recovery Behavior of BFe10-1-2 Cupronickel Alloy during Hot Working

High Temperature Materials and Processes ◽

10.1515/htmp-2015-0094 ◽

2016 ◽

Vol 35 (10) ◽

pp. 1037-1045 ◽

Cited By ~ 7

Author(s):

Jun Cai ◽

Xiaolu Zhang ◽

Kuaishe Wang ◽

Chengpeng Miao

Keyword(s):

Constitutive Equation ◽

Constitutive Model ◽

Deformation Behavior ◽

Elevated Temperatures ◽

Dynamic Recovery ◽

Hot Deformation Behavior ◽

Absolute Relative Error ◽

Average Absolute Relative Error ◽

Recovery Behavior ◽

Good Agreement

AbstractThe hot deformation behavior of BFe10-1-2 cupronickel alloy was investigated over wide ranges of deformation temperature and strain rate. The physics-based constitutive model was developed to predict the dynamic recovery (DRV) behavior of BFe10-1-2 cupronickel alloy at elevated temperatures. In order to verify the validity of the developed constitutive equation, the correlation coefficient (R) and average absolute relative error (AARE) were introduced to make statistics. The results indicated that the developed constitutive equation lead a good agreement between the calculated and experimental data and can accurately characterize the hot DRV behaviors for the BFe10-1-2 cupronickel alloy.

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A Modified Johnson Cook Constitutive Model for Aermet 100 at Elevated Temperatures

High Temperature Materials and Processes ◽

10.1515/htmp-2016-0096 ◽

2018 ◽

Vol 37 (2) ◽

pp. 163-172 ◽

Cited By ~ 1

Author(s):

Yuan Zhanwei ◽

Li Fuguo ◽

Ji Guoliang

Keyword(s):

Elevated Temperatures ◽

Type Model ◽

Strain Rates ◽

Compression Tests ◽

Accuracy Requirement ◽

Absolute Relative Error ◽

Average Absolute Relative Error ◽

Wide Range ◽

Multivariate Nonlinear Regression ◽

Jc Model

AbstractThe predicted flow behaviors of Aermet 100 steel were analyzed within a wide range of temperatures of 1,073 K–1,473 K and strain rates of 0.01 s–1–50 s–1 based on isothermal compression tests. Using the original Johnson Cook (JC) model and a modified Johnson Cook (MJC) model, the constitutive equations were constructed in the case of elevated temperatures. For both the JC and MJC, and the previously studied (Arrhenius-type model and double-multivariate nonlinear regression (DMNR)) models, their respective predictability levels were evaluated by contrasting both the correlation coefficient R and the average absolute relative error (AARE). The results showed that the prediction from the three models meet the accuracy requirement based on the experimental data, the only exception being the JC model. By comparing the predictability and numbers of material constants involved, the modified Johnson Cook model is regarded as an excellent choice for predicting the flow behaviors of Aermet 100 steel within the range being studied.

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High-Temperature Flow Behaviour and Constitutive Equations for a TC17 Titanium Alloy

High Temperature Materials and Processes ◽

10.1515/htmp-2017-0145 ◽

2019 ◽

Vol 38 (2019) ◽

pp. 168-177 ◽

Cited By ~ 1

Author(s):

Liu Shi-feng ◽

Shi Jia-min ◽

Yang Xiao-kang ◽

Cai Jun ◽

Wang Qing-juan

Keyword(s):

Titanium Alloy ◽

High Temperature ◽

Constitutive Equation ◽

Constitutive Equations ◽

Deformation Behaviour ◽

High Temperature Deformation ◽

Temperature Deformation ◽

Compression Tests ◽

Average Absolute Relative Error ◽

Wide Range

AbstractIn this study, the high-temperature deformation behaviour of a TC17 titanium alloy was investigated by isothermal hot compression tests in a wide range of temperatures (973–1223 K) and strain rates (0.001–10 s−1). Then, the constitutive equations of different phase regimes (α + β and single β phases) were developed on the basis of experimental stress-strain data. The influence of the strain has been incorporated in the constitutive equation by considering its effect on different material constants for the TC17 titanium alloy. Furthermore, the predictability of the developed constitutive equation was verified by the correlation coefficient and average absolute relative error. The results indicated that the obtained constitutive equations could predict the high-temperature flow stress of a TC17 titanium alloy with good correlation and generalization.

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Prediction of High Temperature Flow Stress for AISI 4120 Steel during Hot Compression

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.233.339 ◽

2012 ◽

Vol 233 ◽

pp. 339-342 ◽

Cited By ~ 1

Author(s):

Ming Ping Zou ◽

Wu Jiao Xu ◽

Peng Cheng Wang

Keyword(s):

High Temperature ◽

Flow Stress ◽

Constitutive Equation ◽

Constitutive Equations ◽

Good Prediction ◽

Compression Tests ◽

Absolute Relative Error ◽

Constitutive Analysis ◽

Average Absolute Relative Error ◽

Deformation Behaviors

To investigate the hot deformation behaviors of AISI 4120 steel, isothermal compression tests were conducted using Gleeble-1500 thermal-mechanical simulator in the temperature range of 1073-1373K with the strain rate of 0.01-10s-1. The hyperbolic sine law in Arrhenius type is used in the constitutive modeling for AISI 4120. The influence of strain is incorporated in constitutive analysis by considering the effect of strain on material constants α, n, Q and ln A. The flow stress values predicted by the developed constitutive equations show a good agreement with experimental results, which reveals that the developed constitutive equations could give an accurate and precise prediction for the high temperature flow behaviors of AISI 4120 steel. The predictability of developed constitutive equation was further quantified in terms of correlation coefficient (R) and average absolute relative error (AARE). The R and AARE were found to be 0.9847 and 8.0372% respectively, which reflects the good prediction capabilities of the developed constitutive equation.

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Dynamic Recrystallization Behavior of Mg-Gd-Y-Zr Alloy during Hot Compression

Materials Science Forum ◽

10.4028/www.scientific.net/msf.849.181 ◽

2016 ◽

Vol 849 ◽

pp. 181-185 ◽

Cited By ~ 1

Author(s):

Shi Lun Yu ◽

Yong Hao Gao ◽

Chu Ming Liu ◽

Hong Chao Xiao

Keyword(s):

Dynamic Recrystallization ◽

Strain Rate ◽

Volume Fraction ◽

Peak Stress ◽

Critical Conditions ◽

Recrystallization Behavior ◽

Compression Tests ◽

Dynamic Recrystallization Behavior ◽

Increasing Temperature ◽

The Cost

Dynamic recrystallization behavior of Mg-8.0Gd-3.0Y-0.5Zr (wt.%) alloy and the critical conditions corresponding to the onset of dynamic recrystallization were investigated using uniaxial compression tests conducted at temperatures ranging from 350 °C to 500 °C and strain rates ranging from 0.001 s-1 to 1 s-1. Results show that increasing temperature and/or decreasing strain rate can enhance the process of dynamic recrystallization of Mg-8.0Gd-3.0Y-0.5Zr alloy and lower the peak stress and corresponding strain. However, decreasing temperature and/or increasing strain rate can promote the occurrence of twin dynamic recrystallization (TDRX) within the original grains at the cost of reducing the total volume fraction of dynamically recrystallized grains in the microstructure. Besides, the critical stress and strain corresponding to the onset of dynamic recrystallization of Mg-8.0Gd-3.0Y-0.5Zr at 400 °C and 0.1 s-1 are 173MPa and 0.13, respectively.

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A Modified Double Multiple Nonlinear Regression Constitutive Equation for Modeling and Prediction of High Temperature Flow Behavior of BFe10-1-2 Alloy

High Temperature Materials and Processes ◽

10.1515/htmp-2016-0123 ◽

2018 ◽

Vol 37 (1) ◽

pp. 75-87

Author(s):

Jun Cai ◽

Kuaishe Wang ◽

Jiamin Shi ◽

Wen Wang ◽

Yingying Liu

Keyword(s):

Flow Stress ◽

Constitutive Equation ◽

Strain Rate ◽

Nonlinear Regression ◽

Flow Behavior ◽

Strain Rate Range ◽

Compression Tests ◽

Constitutive Analysis ◽

Average Absolute Relative Error ◽

Wide Range

AbstractConstitutive analysis for hot working of BFe10-1-2 alloy was carried out by using experimental stress–strain data from isothermal hot compression tests, in a wide range of temperature of 1,023~1,273 K, and strain rate range of 0.001~10 s–1. A constitutive equation based on modified double multiple nonlinear regression was proposed considering the independent effects of strain, strain rate, temperature and their interrelation. The predicted flow stress data calculated from the developed equation was compared with the experimental data. Correlation coefficient (R), average absolute relative error (AARE) and relative errors were introduced to verify the validity of the developed constitutive equation. Subsequently, a comparative study was made on the capability of strain-compensated Arrhenius-type constitutive model. The results showed that the developed constitutive equation based on modified double multiple nonlinear regression could predict flow stress of BFe10-1-2 alloy with good correlation and generalization.

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Strain Compensation Constitutive Model and Parameter Optimization for Nb-Contained 316LN

Metals ◽

10.3390/met9020212 ◽

2019 ◽

Vol 9 (2) ◽

pp. 212 ◽

Cited By ~ 6

Author(s):

Jingdan Li ◽

Jiansheng Liu

Keyword(s):

Flow Stress ◽

Constitutive Model ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Compression Tests ◽

Continuous Dynamic Recrystallization ◽

Transmission Electron ◽

Strain Compensation ◽

Temperature Ranges ◽

Continuous Dynamic

Hot deformation behavior of Nb-contained 316LN was investigated using a series of compression tests performed on a Gleeble-1500D simulator at temperature of 950–1200 °C and strain rate of 0.01~1 s−1. Based on the strain compensation method, a modified Arrhenius constitutive model considering the comprehensive effects of temperature, strain rate, and strain on flow stress was established, and the accuracy of the proposed model was evaluated by introducing correlation coefficient (R) and average relative error (AARE). The values of R and AARE were calculated as 0.995 and 4.48%, respectively, proving that the modified model has a high accuracy in predicting the flow stress of Nb-contained 316LN. The microstructure evolution and the dynamic recrystallization (DRX) mechanism of the experimental material were explicated by optical microscopy (OM), electron back scattered diffraction (EBSD), and transmission electron microscopy (TEM). It was found that continuous dynamic recrystallization (CDRX) characterized by subgrain evolution and discontinuous dynamic recrystallization (DDRX) featured by grain boundary nuclei are two main dynamic recrystallization (DRX) mechanisms of Nb-contained 316LN. Furthermore, based on the results of microstructure analyses, optimum parameters were obtained as temperature ranges of 1100~1200 °C and strain rate ranges of 0.01~1 s−1.

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Constitutive Equations for Describing the Warm and Hot Deformation Behavior of 20Cr2Ni4A Alloy Steel

Metals ◽

10.3390/met10091169 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1169

Author(s):

Haoran Wang ◽

Wei Wang ◽

Ruixue Zhai ◽

Rui Ma ◽

Jun Zhao ◽

...

Keyword(s):

Flow Stress ◽

Alloy Steel ◽

Relative Error ◽

Constitutive Equations ◽

Type Equation ◽

Coefficient Of Determination ◽

Original Strain ◽

Compression Tests ◽

Absolute Relative Error ◽

Average Absolute Relative Error

Isothermal hot compression tests of 20Cr2Ni4A alloy steel were performed under temperatures of 973–1273 K and strain rates of 0.001–1 s−1. The behavior of the flow stress of 20Cr2Ni4A alloy steel at warm and hot temperatures is complicated because of the influence of the work hardening, the dynamic recovery, and the dynamic recrystallization. Four constitutive equations were used to predict the flow stress of 20Cr2Ni4A alloy steel, including the original strain-compensated Arrhenius-type (osA-type) equation, the new modified strain-compensated Arrhenius-type (msA-type) equation, the original Hensel–Spittel (oHS) equation and the modified Hensel–Spittel (mHS) equation. The msA-type and mHS are developed by revising the deformation temperatures, which can improve prediction accuracy. In addition, we propose a new method of solving the parameters by combining a linear search with multiple linear regression. The new solving method is used to establish the two modified constitutive equations instead of the traditional regression analysis. A comparison of the predicted values based on the four constitutive equations was performed via relative error, average absolute relative error (AARE) and the coefficient of determination (R2). These results show the msA-type and mHS equations are more accurate and efficient in terms of predicting the flow stress of the 20Cr2Ni4A steel at elevated temperature.

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