Modeling Compression and Tension Reloads in Copper Prestrained by Rolling

2007 ◽  
Vol 539-543 ◽  
pp. 3383-3388 ◽  
Author(s):  
Irene J. Beyerlein ◽  
Carlos N. Tomé
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Single Crystal ◽  
Strain Path ◽  
Transverse Direction ◽  
Flow Curves ◽  
Hardening Law ◽  
Slip Activity ◽  
Directional Anisotropy ◽  
Planar Dislocation

A constitutive model is applied to predict the flow stress of an fcc material up to 30% straining after rolling to reductions of 19%, 39%, and 50%. The model makes use of a single crystal hardening law which appreciates the directional anisotropy produced by planar dislocation boundaries, Bauschinger effects, and dissolution of substructure by new slip activity invoked by changes in strain path. Anisotropy between axial testing in the rolling (RD) versus the transverse direction (TD) and a tensioncompression stress- differential in RD are predicted. These and other characteristics of the flow curves are linked to changes in slip activity when deformation transitions from rolling to axial testing.

scholarly journals A Modified Constitutive Model for the Description of the Flow Behavior of the Ti-10V-2Fe-3Al Alloy during Hot Plastic Deformation

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 844 ◽  
Author(s):  
Wang ◽  
Shen ◽  
Zhang ◽  
Ning
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Strain Rate ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Strain Rates ◽  
Compression Tests ◽  
Flow Curves ◽  
Deformation Parameters ◽  
Predicted Values

The hot deformation behavior of the aerospace Ti-10-2-3 alloy was investigated by isothermal compression tests at temperatures of 740 to 820 °C and strain rates of 0.0005 to 10 s−1. The results show that the studied alloy is extremely sensitive to deformation parameters, like the temperature and strain rate. The temperature mainly affects the magnitude of flow stress at larger strains, while the strain rate not only affects the value of flow stress but also the shape of the flow curves. At low strain rates, the flow stress increases with strain, followed by a broad peak and then remains almost constant. At high strain rates, the flow curves exhibit a hardening to a sharp peak at small strains, followed by a rapid dropping to a plateau caused by dynamic softening. In order to describe such flow behavior, a constitutive model considering the effect of deformation parameters was developed as an extension of an existing constitutive model. The modified constitutive model (MC) was obtained based on the original constitutive model (OC) by introducing a new parameter to compensate for the error between the experimental data and predicted values. Compared to the original model, the developed model provides a better description of the flow behavior of Ti-10-2-3 alloy at elevated temperatures over the specified deformation domain.

scholarly journals Understanding the Strain Path Effect on the Deformed Microstructure of Single Crystal Pure Aluminum

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1189
Author(s):  
Yingjue Xiong ◽  
Qinmeng Luan ◽  
Kailun Zheng ◽  
Wei Wang ◽  
Jun Jiang
Keyword(s):  
Strain Rate ◽  
Single Crystal ◽  
Strain Path ◽  
Mechanical Response ◽  
Pure Aluminum ◽  
Lattice Rotation ◽  
Softening Behavior ◽  
Theoretical Support ◽  
Commercial Applications ◽  
Electron Back Scattered Diffraction

During plastic deformation, the change of structural states is known to be complicated and indeterminate, even in single crystals. This contributes to some enduring problems like the prediction of deformed texture and the commercial applications of such material. In this work, plane strain compression (PSC) tests were designed and implemented on single crystal pure aluminum to reveal the deformation mechanism. PSC tests were performed at different strain rates under strain control in either one-directional or two-directional compression. The deformed microstructures were analyzed according to the flow curve and the electron back-scattered diffraction (EBSD) mappings. The effects of grain orientation, strain rate, and strain path on the deformation and mechanical response were analyzed. Experimental results revealed that the degree of lattice rotation of one-dimensional compression mildly dependents on cube orientation, but it is profoundly sensitive to the strain rate. For two-dimensional compression, the softening behavior is found to be more pronounced in the case that provides greater dislocations gliding freeness in the first loading. Results presented in this work give new insights into aluminum deformation, which provides theoretical support for forming and manufacturing of aluminum.

Constitutive Modeling for Flow Stress Behavior of Nimonic 80A Superalloy During Hot Deformation Process

2016 ◽  
Vol 35 (3) ◽  
pp. 327-336 ◽  
Author(s):  
Sendong Gu ◽  
Liwen Zhang ◽  
Chi Zhang ◽  
Wenfei Shen
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Hot Deformation ◽  
Critical Strain ◽  
Volume Fraction ◽  
Constitutive Models ◽  
Avrami Equation ◽  
Peak Strain ◽  
Compression Tests ◽  
Nimonic 80A

AbstractThe hot deformation characteristics of nickel-based alloy Nimonic 80A were investigated by isothermal compression tests conducted in the temperature range of 1,000–1,200°C and the strain rate range of 0.01—5 s–1on a Gleeble-1500 thermomechanical simulator. In order to establish the constitutive models for dynamic recrystallization (DRX) behavior and flow stress of Nimonic 80A, the material constantsα,nand DRX activation energyQin the constitutive models were calculated by the regression analysis of the experimental data. The dependences of initial stress, saturation stress, steady-state stress, dynamic recovery (DRV) parameter, peak strain, critical strain and DRX grain size on deformation parameters were obtained. Then, the Avrami equation including the critical strain for DRX and the peak strain as a function of strain was established to describe the DRX volume fraction. Finally, the constitutive model for flow stress of Nimonic 80A was developed in DRV region and DRX region, respectively. The flow stress values predicted by the constitutive model are in good agreement with the experimental ones, which indicates that the constitutive model can give an accurate estimate for the flow stress of Nimonic 80A under the deformation conditions.

scholarly journals A Flow Stress Model of 300M Steel for Isothermal Tension

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 252
Author(s):  
Rongchuang Chen ◽  
Shiyang Zhang ◽  
Xianlong Liu ◽  
Fei Feng
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Tensile Deformation ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Model Parameters ◽  
Average Deviation ◽  
Cross Sectional ◽  
300M Steel

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.

A Simple Constitutive Model for Prediction of Single-Peak Flow Curves Under Hot Working Conditions

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Roxana Baktash ◽  
Hamed Mirzadeh
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Peak Flow ◽  
Rate Sensitivity ◽  
Peak Strain ◽  
Flow Curves ◽  
Hollomon Parameter ◽  
Proposed Model ◽  
Stress Coefficient ◽  
Hollomon Equation

The hot flow stress of a typical stainless steel was modeled by the Hollomon equation, a modified form of the Hollomon equation, and another modified form based on the Fields–Backofen equation. The coupled effect of the deformation temperature and strain rate was also taken into account in the proposed formulae by consideration of the Zener–Hollomon parameter or dependency of the constants on temperature. The modified Fields–Backofen equation was found to be appropriate for prediction of flow stress, in which the incorporation of peak strain and consideration of temperature dependencies of the strain rate sensitivity and the stress coefficient were found to be beneficial. Moreover, the simplicity of the proposed model justifies its applicability for expressing hot flow stress characterizing dynamic recrystallization (DRX).

scholarly journals Study on Dynamic Mechanical Properties and Constitutive Model Construction of TC18 Titanium Alloy

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 44 ◽  
Author(s):  
Changming Zhang ◽  
Anle Mu ◽  
Yun Wang ◽  
Hui Zhang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Flow Stress ◽  
Yield Strength ◽  
Constitutive Model ◽  
Testing Machine ◽  
Dynamic Mechanical Properties ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Different Temperatures

In order to investigate the static and dynamic mechanical properties of TC18 titanium alloy, the quasi-static stress–strain curve of TC18 titanium alloy under room temperature was obtained by DNS 100 electronic universal testing machine (Changchun Institute of Mechanical Science Co., Ltd., Changchun, China). Meanwhile, the flow stress–strain curves under different temperatures and strain rates are analyzed by split Hopkinson pressure bar (SHPB) device with synchronous assembly system. On the basis of the two experimental data, the JC constitutive model under the combined action of high temperature and impact load is established using the linear least squares method. The results show the following: the yield strength and flow stress of TC18 titanium alloy increase slowly with the increase of the strain rate, and the strain value corresponding to the yield strength is reduced. With the increase of strain, the flow stress increases at first and then decreases at different temperatures. The strain value corresponding to the transition point rises with the temperature increase, and the corresponding stress value remains basically unchanged. With the increase of experimental temperature, the flow stress shows a downward trend, and the JC constitutive model can predict the plastic flow stress well.

Plastic Flow Stress and Constitutive Model for H96 Brass Alloy

2015 ◽  
Vol 782 ◽  
pp. 130-136 ◽  
Author(s):  
Ping Zhou ◽  
Wei Guo Guo ◽  
Hai Hui Wu
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Plastic Flow ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Experimental Results ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Brass Alloy ◽  
Plastic Flow Stress

To explore the thermo-mechanical response of H96 brass alloy, the quasi-static (universal-testing machine) and dynamic (the split Hopkinson pressure bar apparatus) uniaxial compression experiments have been performed under the temperatures from 293 K to 873 K and the strain rates from 0.001 s-1 to 6000 s-1, and the strains over 60% are obtained. Results show that, H96 brass alloy has strong strain hardening behavior, and it becomes weaker with the increasing temperature. In addition, this alloy is sensitive to strain rates; and, it has temperature sensitivity, the dynamic strain aging occurs at the temperature of 473 K and a quasi-static strain rate of 0.001 s-1. Based on the thermal activation dislocation mechanism, paralleled with the experimental results, a plastic flow constitutive model with the physical conception is developed. The model is suitable to predict the plastic flow stress at different temperatures and strain rates. According to comparing results, the model predictions are in good agreement with the experimental results.

Determination of the Flow Stress of Ti6Al4V Based on Cutting Experiment and Optimization

2009 ◽  
Vol 407-408 ◽  
pp. 533-537 ◽  
Author(s):  
Yue Feng Yuan ◽  
Wu Yi Chen ◽  
Dong Liu
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Constitutive Model ◽  
Cutting Force ◽  
Simple Method ◽  
Cutting Experiment ◽  
Titanium Alloy Ti6al4v ◽  
Jc Model ◽  
Cutting Simulations

A methodology to determine the flow stress of material was presented and Johnson–Cook (JC) constitutive model of titanium alloy Ti6Al4V was obtained based on cutting experiment and optimization. This JC model was verified by comparison between simulations with different JC models respectively and experiment. It showed that the accuracy of simulation of cutting force has an increase and the new model is more suitable for cutting simulations. This simple method could improve the accuracy and reliability of the cutting simulation, and could be used to establish the constitutive model of workpiece with more accuracy.

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