Modeling and Prediction of Hot Deformation Flow Curves

Mirzadeh, Hamed; Cabrera, J.M.; Najafizadeh, A.

doi:10.1007/s11661-011-0836-3

Cited by 102 publications

(39 citation statements)

References 89 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a result, considerable research has been carried out to model the flow stress of metals and alloys. [4][5][6][7][8][9] A constitutive relationship is a mathematical representation of flow stress as a function of temperature, strain rate, strain, and occasionally other factors such as chemical composition. [9,10] Usually, the effect of temperature and strain rate is incorporated in the ZenerHollomon parameter (Z), which is a temperaturecompensated strain rate parameter.…”

Section: Introductionmentioning

confidence: 99%

A Simplified Approach for Developing Constitutive Equations for Modeling and Prediction of Hot Deformation Flow Stress

Mirzadeh

2015

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

A comparative study was carried out on the appropriateness of hyperbolic sine, power, and exponential descriptions of Zener-Hollomon parameter (Z) in prediction of high-temperature flow stress by consideration of the effect of strain. It was shown that the main problem of the conventional strain compensation approach is the implementation of the constitutive equations to find the strain-dependent material constants, especially the hot deformation activation energy (Q), at constant strain values, which arises from the change in the microstructure of the material at a given strain for different deformation conditions (different Z values). Subsequently, a simplified approach for each constitutive equation, mainly by taking Q from the peak stress analysis, was proposed to solve this issue. This also resulted in significantly better prediction abilities for unseen deformation conditions and effectively simplified the required calculations.

show abstract

Section: Introductionmentioning

confidence: 99%

A Simplified Approach for Developing Constitutive Equations for Modeling and Prediction of Hot Deformation Flow Stress

Mirzadeh

2015

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Notably, the effects of work hardening and softening mechanisms are considered during the plastic deformation, and it is necessary to remove the elastic stage of the flow curves [29]. Figure 2 shows the θ-ε and θ-σ curves of the Fe-6.5wt.…”

Section: Flow Behavior Characteristicsmentioning

confidence: 99%

“…The positive values of θ indicate that the work hardening exceeds the dynamic softening. The peak stress and corresponding strain can be obtained from the flow curve, whereas the true peak stress (σ ) and strain (ε ) can be calculated from the θ-ε and θ-σ curves when θ = 0 [29], as presented in Table 2. It can be observed that the work hardening rate increased with the decrease of temperature and increase of strain rate, as shown in Figure 2a.…”

Section: Flow Behavior Characteristicsmentioning

confidence: 99%

Flow Behavior Characteristics and Processing Map of Fe-6.5wt. %Si Alloys during Hot Compression

Wen

Han

Zhang

et al. 2018

Metals

View full text Add to dashboard Cite

Abstract:The flow behavior of . %Si alloys during hot compression was investigated at temperatures 650-950 • C and strain rates 0.01-10 s −1 . The results showed that the flow stress depended distinctly on the deformation temperatures and strain rates. The flow stress and work hardening rate increased with the decrease of temperature and the increase of strain rate. The activation energy under all the deformation conditions was calculated to be 410 kJ/mol. The constitutive equation with hyperbolic sine function and Zener-Hollomon parameter was developed. The peak stress, critical stress, and steady-state stress could be represented as σ = A + Bln(Z/A). Dynamic recrystallization occurred under the deformation conditions where the values of Z were lower than 10 20 . Processing maps were established to optimize the processing parameters. The power dissipation efficiency decreased in the high temperature and low strain rate region, increased in the high temperature and high strain rate region, and remained unchanged in other regions with the increase of true strain. Furthermore, the unstable area expanded. The true strain of 0.7 was the optimum reduction according to the processing map. Based on the analysis of surface quality, microstructures, and ordered structures, the optimized processing parameters for the Fe-6.5wt. %Si alloys were the temperature and strain rate of higher than 900 • C and 0.01-10 s −1 , respectively, or 800-900 • C and lower than 0.4 s −1 , respectively.

show abstract

“…The modeling of hot flow stress and the prediction of flow curves are important in metal-forming processes from the mechanical and metallurgical standpoints because this is an essential part of the numerical simulations in finite element codes. As a result, considerable researches have been focused on this subject in recent years [6,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

A simple constitutive model for predicting flow stress of medium carbon microalloyed steel during hot deformation

2015

Self Cite

View full text Add to dashboard Cite

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 1 A Simple Constitutive Model for Predicting Flow Stress of Medium Carbon Microalloyed Steel during Hot Deformation AbstractThe constitutive behavior of a medium carbon microalloyed steel during hot working over a wide range of temperatures and strain rates was studied using the Johnson-Cook (JC) model, the Hollomon equation, and their modifications. The original JC model was not able to predict the softening part of the flow curves and the subsequent modifications of the JC model to account for the softening stage and the strain dependency of constants were not satisfactory owing to the uncoupled nature of the JC approach regarding strain rate and temperature. The coupled effect of these variables was considered in the form of Zener-Hollomon parameter (Z) and the constants of the Hollomon equation were related to Z. This modification was found to be useful for the hardening stage but the overall consistency between the experimental flow curves and the calculated ones was not good. Therefore, a simple constitutive model was proposed in the current work, in which by utilization of the peak stress and strain into the Hollomon equation, good prediction abilities were attained. Conclusively, the proposed model can be considered as an efficient one for modeling and prediction of hot deformation flow curves.

show abstract

Modeling and Prediction of Hot Deformation Flow Curves

Cited by 102 publications

References 89 publications

A Simplified Approach for Developing Constitutive Equations for Modeling and Prediction of Hot Deformation Flow Stress

A Simplified Approach for Developing Constitutive Equations for Modeling and Prediction of Hot Deformation Flow Stress

Flow Behavior Characteristics and Processing Map of Fe-6.5wt. %Si Alloys during Hot Compression

A simple constitutive model for predicting flow stress of medium carbon microalloyed steel during hot deformation

Contact Info

Product

Resources

About