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

2018 ◽  
Author(s):  
Shibo Wen ◽  
Chaoyu Han ◽  
Bao Zhang ◽  
Yongfeng Liang ◽  
Feng Ye ◽  
...  
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Processing Map ◽  
Flow Behavior ◽  
True Strain ◽  
Processing Parameters ◽  
Hot Compression ◽  
Strain Rates ◽  
Rate Region

The flow behavior of Fe-6.5wt.%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 1020. 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.

scholarly journals Hot Deformation Behavior and Processing Map of High-Strength Nickel Brass

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 782 ◽  
Author(s):  
Qiang Liang ◽  
Xin Liu ◽  
Ping Li ◽  
Xianming Zhang
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Processing Map ◽  
Flow Behavior ◽  
High Strength ◽  
Strain Rates ◽  
Compression Tests ◽  
Technical Parameters ◽  
Gleeble 3500

The flow behavior of a new kind of high-strength nickel brass used as automobile synchronizer rings was investigated by hot compression tests with a Gleeble-3500 isothermal simulator at strain rates ranging from 0.01 to 10 s−1 and a wide deformation temperature range of 873–1073K at intervals of 50 K. The experimental results show that flow stress increases with increasing strain rate and decreasing deformation temperature, and discontinuous yielding appeared in the flow stress curves at higher strain rates. A modified Arrhenius constitutive model considering the compensation of strain was established to describe the flow behavior of this alloy. A processing map was also constructed with strain of 0.3, 0.6, and 0.9 based on the obtained experimental flow stress–strain data. In addition, the optical microstructure evolution and its connection with the processing map of compressed specimens are discussed. The predominant deformation mechanism of Cu-Ni-Al brass is dynamic recovery when the deformation temperature is lower than 973 K and dynamic recrystallization when the deformation temperature is higher than 973 K according to optical observation. The processing map provides the optimal hot working temperature and strain rate, which is beneficial in choosing technical parameters for this high-strength alloy.

The Optimal Selection of Extrusion Parameters of As-Cast TC27 Titanium Alloy Based on Processing-Map

2017 ◽  
Vol 898 ◽  
pp. 1134-1139
Author(s):  
Xue Fei Li ◽  
Ai Xue Sha ◽  
Xu Huang ◽  
Li Jun Huang
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Processing Map ◽  
True Strain ◽  
Great Influence ◽  
Stable Condition ◽  
Dynamic Materials ◽  
Dynamic Materials Model ◽  
Selection Of

The hot deformation behavior of TC27 titanium alloy at the temperatures of 900-1150 °C and the strain rate of 0.01-10 s-1, the height reduction of 70%, was investigated in the isothermal compression test to identify the optimal extrusion parameters. The processing-map of TC27 titanium alloy was constructed based on dynamic materials model (DMM) and principle of Prasad*s instability. The conclusion shows that temperature and strain rate of deformation had a great influence on flow stress. At the beginning of deformation, the flow stress increased quickly with the augment of true strain and decreased slowly after flow stress reaching to the maximum value. Finally, flow stress tended to relatively stable condition. The flow stress decreased with the increase of temperature and increased with the increase of strain rate. The TC27 titanium alloy was sensitive to temperature and strain rate. Processing-map exhibited two peak efficiencies of power dissipation; one peak was 49% at 900°C/0.01 s-1, which dynamic recovery occured. The other peak was also 49% at 1050 °C /0.01s-1, which dynamic recrystallization occured in the domain. Besides, there were two instability areas in the processing-map which should be avoided during the extrusion. Therefore, in order to obtain the satisfactory properties, the parameters that 1050 °C and 0.01 s-1 were selected in the extrusion.

Study on High Temperature Flow Stress Model of As-cast SA508-3 Low Alloy Steel

2020 ◽  
Vol 831 ◽  
pp. 25-31
Author(s):  
Pan Fei Fan ◽  
Jian Sheng Liu ◽  
Hong Ping An ◽  
Li Li Liu
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Alloy Steel ◽  
Flow Behavior ◽  
Peak Stress ◽  
Stress Model ◽  
Low Alloy Steel ◽  
Two Stage ◽  
Flow Stress Model

In order to obtain the high temperature flow behavior of as-cast SA508-3 low alloy steel, the stress-strain curves of steel are obtained by Gleeble thermal simulation compression test at deformation temperature 800°C-1200°C and strain rate 0.001s-1-1s-1. Based on Laasraoui two-stage flow stress model, a high temperature flow stress model is established by multiple linear regression method. The results show that the peak stress characteristics are not obvious at low temperature and high strain rate, which is a typical dynamic recovery characteristic. Meanwhile, the peak stress characteristics are obvious at high temperature and low strain rate, which is a typical dynamic recrystallization characteristic. By means of the comparisons between experiments and calculations, the Laasraoui two-stage flow stress model can truly reflect flow behavior of steel at high temperature, which provides theoretical guidance for the hot deformation of the steel.

Hot Deformation Behaviors of SiCp/Al Composites

2014 ◽  
Vol 1058 ◽  
pp. 165-169 ◽  
Author(s):  
Shi Ming Hao ◽  
Jing Pei Xie
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
True Strain ◽  
Constant Strain Rate ◽  
Hot Compression ◽  
Compression Tests ◽  
Sensitive Material ◽  
2024 Aluminum Alloy ◽  
Deformation Behaviors

The hot deformation behaviors of 30%SiCp/2024 aluminum alloy composites was studied by hot compression tests using Gleeble-1500 thermomechanical simulator at temperatures ranging from 350-500°C under strain rates of 0.01-10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 183.251 kJ/mol. The optimum hot working conditions for this material are suggested.

scholarly journals Investigation on the Thermal Deformation Behavior of the Nickel-Based Superalloy Strengthened by γ′ Phase

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 125
Author(s):  
Haiping Wang ◽  
Dong Liu ◽  
Jianguo Wang ◽  
Yongzhao Shi ◽  
Yong Zheng ◽  
...  
Keyword(s):  
Flow Stress ◽  
Power Dissipation ◽  
Deformation Behavior ◽  
Processing Map ◽  
Flow Instability ◽  
True Strain ◽  
Processing Condition ◽  
Strain Rates ◽  
Processing Maps ◽  
Nickel Based Superalloy

The isothermal compression tests of the nickel-based superalloy Waspaloy were carried out under various temperatures from 1040 to 1120 °C and strain rates from 0.01 to 10 s−1 with the height reduction of 60% and the flow stress curves were obtained. The curves show that the flow stress is greatly affected by the temperature and strain rates. Regression analysis of the experimental results was carried out to learn about the deformation behavior through the Arrhenius equation and came to the conclusion that the activation energy of Waspaloy is 669.7 kJ/mol. The constitutive equation of the Waspaloy was constructed. Meanwhile, the processing maps of the Waspaloy for the power dissipation and the flow instability were constructed. The processing map of the power dissipation and the flow instability depicts that the strain plays a major role in the processing maps. The instability zone is prone to appear at higher strain rates with the increasing strains. According to the instability processing map, there are three unsafe regimes around 1040–1120 °C/1.5–10 s−1, 1040–1080 °C/0.02–0.1 s−1 and 1110–1120 °C/0.02–0.3 s−1 that should be avoided during deformation process. The power dissipation maps show that the maximum dissipation is prone to appear at low strain rates (0.01 s−1) when the strain is about 0.1~0.6 while at middle strain rates (0.1–1 s−1) when the strain is over 0.6, and when the true strain is 0.9, the optimum processing condition is around 1060–1120 °C/0.1–1 s−1. The dynamic microstructures under different temperatures and strain rates were also obtained. We concluded that lower strain rates and higher temperatures are more applicable to obtain fully-recrystallized microstructures. Based on the instability maps and the power dissipation maps and the dynamic microstructures, the optimum deformation conditions are determined to be around 1080–1100 °C/0.1–1 s−1 and 1040–1120 °C/0.01 s−1.

Deformation Behavior and Processing Map of High Temperature of TC21 Titanium Alloy

2013 ◽  
Vol 274 ◽  
pp. 427-431 ◽  
Author(s):  
Ying Gong
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Processing Map ◽  
True Strain ◽  
Strain Rate Range ◽  
Peak Region ◽  
Working Zone ◽  
Dynamic Materials

The compression test on TC21 titanium alloy was carried out in the temperature range of 860~940oC and the strain rate range of 0.01~10s-1 on Gleeble-1500D hot simulation machine. And the hot deformation behavior was studied. The processing map was calculated and analyzed according the dynamic materials model. It is found that the flow stress of TC21 decreases with the increasing of the temperature and the decreasing of the strain rate. The flow stress curves are characterized by steady state at low strain rate( s-1）but discontinuous yield at high strain rate( s-1). The processing map established at the true strain of 0.4 shows that there are three regions, instability and safe and peak region, and the efficiencies of power dissipation are 0~25%，31%~37% and 43%~49% respectively. The peak region is the optimum hot working zone of TC21 titanium alloy.

scholarly journals Constitutive Analysis on High-Temperature Flow Behavior of 3Cr-1Si-1Ni Ultra-High Strength Steel for Modeling of Flow Stress

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 42 ◽  
Author(s):  
Bingwang Lei ◽  
Gaoqiang Chen ◽  
Kehong Liu ◽  
Xin Wang ◽  
Xiaomei Jiang ◽  
...  
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Constitutive Equations ◽  
High Strength Steel ◽  
Flow Behavior ◽  
High Strength ◽  
Strain Dependence ◽  
Constitutive Analysis ◽  
Ultra High Strength Steel

High-temperature plastic flow is the underlying process that governs the product quality in many advanced metal manufacturing technologies, such as extrusion, rolling, and welding. Data and models on the high-temperature flow behavior are generally desired in the design of these manufacturing processes. In this paper, quantitative constitutive analysis is carried out on 3Cr-1Si-1Ni ultra-high strength steel, which sheds light on the mathematic relation between the flow stress and the thermal-mechanical state variables, such as temperature, plastic strain, and strain rate. Particularly, the hyperbolic-sine equation in combination with the Zener-Hollomon parameter is shown to be successful in representing the effect of temperature and strain rate on the flow stress of the 3Cr-1Si-1Ni steel. It is found that the flow stress of the 3Cr-1Si-1Ni steel is significantly influenced by strain. The strain-dependence on flow stress is not identical at different temperatures and strain rates. In the constitutive model, the influence of strain in the constitutive analysis is successfully implemented by introducing strain-dependent constants for the constitutive equations. Fifth-order polynomial equations are employed to fit the strain-dependence of the constitutive constant. The proposed constitutive equations which considers the compensation of strain is found to accurately predict flow stress of the 3Cr-1Si-1Ni steel at the temperatures ranging from 800 °C to 1250 °C, strain rate ranging from 0.01/s to 10/s, and strain ranging from 0.05 to 0.6.

scholarly journals Flow Stress Curve Modification and Constitutive Model of 20CrMoA Steel during Warm Deformation

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1602
Author(s):  
Sheng Xu ◽  
Xuedao Shu ◽  
Shuxin Li ◽  
Ji Chen
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Strain Rate ◽  
Deformation Temperature ◽  
True Strain ◽  
Processing Parameters ◽  
Flow Softening ◽  
Warm Deformation ◽  
Temperature Range ◽  
Lower Temperature

The warm deformation behavior of 20CrMoA steel at the temperature of 873–1123 K and the strain rate of 0.01−10 s−1 was investigated to obtain its processing property and optimum processing parameters. The true stress-true strain curves showed that flow stress reaches the peak rapidly, followed by slow decrease till reaching a steady state. This suggests a flow softening of dynamic recovery. The stress dropped with increasing deformation temperature and decreasing strain rate. The reduction became more distinct at lower temperature and higher strain rate due to flow softening caused by deformation heat. In the temperature range of 873–973 K, the deformation of 20CrMoA steel was more sensitive to temperature, and the average decline rate of steady stress was 6.9 times larger than that in the temperature range of 1023–1123 K. After modifying the stress curves, a constitutive model was developed for different deformation temperature ranges based on modified curves. The model was in good agreement with the experimental results.

Deformation Behavior and Microstructure Evolution of 6063 Alloy during Hot Compression

2018 ◽  
Vol 913 ◽  
pp. 63-68 ◽  
Author(s):  
Zhu Hua Yu ◽  
Da Tong Zhang ◽  
Wen Zhang ◽  
Cheng Qiu
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Shear Bands ◽  
Hot Compression ◽  
Al Alloy ◽  
Strain Rates ◽  
Compression Tests ◽  
Softening Effect ◽  
6063 Al Alloy ◽  
Gleeble 3500

Hot compression tests of homogenized 6063 Al alloy were carried out in the temperatures range from 390°C to 510°C and strain rates from 1s-1 to 20s-1 on a Gleeble-3500 thermal simulation machine. The results showed that the flow stress decreased with increasing deformation temperature or decreasing strain rate. The dynamic softening effect was more obvious when the alloy was deformed at strain rate of 20 s-1. The Arrhenius-type constitutive equation with strain compensation can accurately describe the flow stress of 6063 aluminum alloy during hot compression. Shear bands appeared in grains interior when the alloy deformed at high strain rates, corresponding to high Zenner-Hollomon (Z) parameters. When deformed under the conditions with low Z parameters, the dynamic recrystallization started occurred.

Constitutive Equation for Elevated Temperature Flow Behavior of Fe-Cr-Ni Preform Reinforced Al-Si-Cu-Ni-Mg Aluminum Composite

2014 ◽  
Vol 633-634 ◽  
pp. 431-435 ◽  
Author(s):  
Ling Zhan Zhou ◽  
Li Ming Yang ◽  
Yin Jiang Peng ◽  
Xiu Rong Zhu
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Flow Behavior ◽  
True Strain ◽  
Casting Process ◽  
Strain Rate Range ◽  
Type Model ◽  
Compression Tests ◽  
Fixed Temperature ◽  
Aluminum Composite

In this paper, squeeze casting process was adopted to produce the Fe-Cr-Ni preform reinforced Al-Si-Cu-Ni-Mg aluminum composite. And then, T6 heat treatment was conducted to enhance the composite’s performance. After which, isothermal compression tests in temperature range of 473-773 K at an interval of 150 K and strain rate range from 0.001 to 10 s-1 were carried out on Gleeble 3500 thermo-mechanical simulation machine. It is found that, for a specific strain rate, the flow stress decreases markedly with temperature increases. And for a fixed temperature, the flow stress generally increases as the strain rate increases. Based on the experimental true stress-true strain data, the Arrhenius type model was established.

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