Hot Deformation Behavior and Microstructural Evolution of Al-Zn-Mg-Cu Alloy with Different Starting Structures

2014 ◽  
Vol 941-944 ◽  
pp. 26-34
Author(s):  
Xiao Dong Zhao ◽  
Hui Qin Chen ◽  
Jian Sheng Liu
Keyword(s):  
Microstructural Evolution ◽  
Hot Deformation ◽  
Deformation Condition ◽  
Large Strains ◽  
Compression Tests ◽  
Cu Alloy ◽  
Coarse Grains ◽  
Deformation Behaviors ◽  
Small Grains ◽  
Sine Equation

Hot Deformation behaviors and microstructural evolution of Al-Zn-Mg-Cu alloy with as-homogenized, as-forged and as-over-aged starting structures were studied at temperatures in the range of 300-420°C, strain rates in the range of 0.01-1s-1, and reductions in the range of 20%-80% by high-temperature compression tests. The flow stresses increase with increasing strain rate or decreasing temperature, which can be described by a hyperbolic-sine equation with the deformation activation energies of 246.35KJ/mol, 188.87KJ/mol and 178.25KJ/mol for the homogenized, the forged and the over-aged samples respectively. At the same deformation condition, the flow stress of the homogenized samples is greater than that of the forged and over-aged samples. For the homogenized samples, dendritic coarse grains elongated along the deformation direction, and interdendritic boundaries within coarse grains disappeared gradually due to diffusion at higher temperatures. When deformation is heavy, microstructures became into homogenous and geometric recrystallization occurs and new small grains appear within the severe elongated grains. For the forged samples, higher temperatures promote dynamic recrystallization. Recrystallized new small grains were developed along prior grain boundaries at large strains. For the over-aged samples, prior grains elongated along the deformation direction, and there is not much more dynamic recrystallized grains observed.

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.

Hot Deformation Behavior and Microstructural Evolution of Mg-Nd-Zn-Zr Magnesium Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 320-326 ◽  
Author(s):  
Wen Xiang Wu ◽  
Li Jin ◽  
Jie Dong ◽  
Zhen Yan Zhang ◽  
Wen Jiang Ding
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Grain Boundaries ◽  
Microstructural Evolution ◽  
Hot Deformation ◽  
Fine Particles ◽  
Volume Fraction ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Average Size

The hot deformation behaviors and microstructural evolution of Mg-3.0Nd-0.2Zn-0.4Zr (wt. %, NZ30K) alloy were investigated by means of the isothermal hot compression tests at temperatures of 350-500 °C with strain rates of 0.001, 0.01, 0.1 and 1s-1. The results showed that the flow stress increased to a peak and then decreased which showed a dynamic flow softening. The flow stress behavior was described by the hyperbolic sine constitutive equation with an average activation energy of 193.8 kJ/mol. The average size of dynamically recrystallized grains of hot deformed NZ30K alloy was reduced by increasing the strain rate and/or decreasing the deformation temperature. A large amount of fine particles precipitated in the grains interior and at the grain boundaries when heated to the compression temperatures and soaked for 5min below 450 °C. However, the volume fraction of particles decreased significantly when soaked for 5 min at 500 °C, and the coarse particles precipitated mainly at the grain boundaries. Hot deformation at the temperature of 500 °C around and at the strain rate range of 0.1s-1 was desirable for NZ30K alloy.

Hot Deformation Behavior of 20CrMnTiH Steel Studied by Johnson-Cook Model and Genetic Algorithm

2014 ◽  
Vol 1035 ◽  
pp. 225-230
Author(s):  
Rong Xia Chai ◽  
Wei Guo ◽  
Chen Guo
Keyword(s):  
Genetic Algorithm ◽  
Hot Deformation ◽  
True Strain ◽  
Model Material ◽  
Model Parameters ◽  
Strain Rates ◽  
Compression Tests ◽  
Deformation Behaviors ◽  
Good Agreement ◽  
Cook Model

Hot compression tests of 20CrMnTiH steel are carried out in the strain rates range from 0.01s-1 to 10s-1 and in the temperature range from 973K to 1123K. The flow behaviors of 20CrMnTiH steel are described based on the analysis of true stress-true strain curves. The flow stress increases with the increasing of strain rate and the decreasing of deforming temperature. Johnson-Cook (J-C) model are used to analyze the hot deformation behaviors. In the constitutive model, material constants are determined based upon the experimental data. Genetic algorithm (GA) is proposed with the aim of optimizing the J-C model parameters. Good agreement is acquired by comparing of the experimental results with predicted results. It validates the efficiency of Johnson-Cook model in describing the material constitutive behavior.

Study on the Flow Stress of the High-Mn Austenitic Steel during Hot Deformation

2013 ◽  
Vol 690-693 ◽  
pp. 2258-2264
Author(s):  
Xin Xu ◽  
Fang Po Li ◽  
Chun Feng ◽  
Peng Wang ◽  
Sheng Yin Song
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Isothermal Compression ◽  
Compression Tests ◽  
Hyperbolic Sine ◽  
Deformation Activation Energy ◽  
Temperature Ranges ◽  
Sine Equation

The flow stress of a high-Mn austenitic Fe-20Mn-3Si-3Al TRIP steel was investigated by isothermal compression tests on Gleeble 3500D thermo-mechanical simulator in the temperature ranges from 900°C to 1100°C and the strain rate ranges from 0.01s-1 to 10s-1. The results show that the flow stress is sensitively dependent on deformation temperature and strain rate, and the flow stress increases with strain rate and decreases with deformation temperature. The flow stress during isothermal compression can be described by the Zener-Hollomon (Z) parameter in the hyperbolic sine equation with the hot deformation activation energy Q of 385.2kJ/mol.

Flow and Densification Behaviors of Sintered P/F-10C50 Steel under Hot Compression

2016 ◽  
Vol 849 ◽  
pp. 811-818
Author(s):  
Biao Guo ◽  
Chang Chun Ge ◽  
Yi Xu ◽  
Qiu Yan Lu ◽  
Sui Cai Zhang
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Hot Compression ◽  
Compression Tests ◽  
Sintered Steel ◽  
Absolute Relative Error ◽  
Average Absolute Relative Error ◽  
Deformation Behaviors

The hot deformation and densification behaviors of sintered P/F-10C50 steel were investigated by hot compression tests on Gleeble-1500 thermal mechanical simulator at the temperature ranging from 900 °C to 1000 °C and the strain rate ranging from 0.1 s-1 to 10 s-1. The flow and densification characteristics of the tested specimens at different deformation temperatures and strain rates were studied. The flow stress of the sintered steel persistently increases until the end of the test as the result of matrix and geometric work hardening. The higher deformation temperature and strain rate are conductive to the healing of the pores and promote the densification of the sintered steel, while the higher deformation temperature and lower strain rate impede the densification. The constitutive equation of the sintered steel is established by the means of stepwise regression. The flow stresses predicted by the established constitutive equation are in good agreement with the experimental values, and the correlation coefficient (R) and the average absolute relative error (AARE) are 0.9931 and 3.52%, respectively. These results demonstrate the hot deformation behaviors of the sintered P/F-10C50 steel are excellently predicted by the established constitutive equation.

Hot Deformation Behaviors of SiCp/2024 Aluminum Composites

2013 ◽  
Vol 833 ◽  
pp. 271-275
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 153.251 kJ/mol. The optimum hot working conditions for this material are suggested.

Microstructural evolution and constitutive models to predict hot deformation behaviors of a nickel-based superalloy

Vacuum ◽  
2017 ◽  
Vol 137 ◽  
pp. 104-114 ◽  
Author(s):  
Y.C. Lin ◽  
Fu-Qi Nong ◽  
Xiao-Min Chen ◽  
Dong-Dong Chen ◽  
Ming-Song Chen
Keyword(s):  
Microstructural Evolution ◽  
Hot Deformation ◽  
Constitutive Models ◽  
Nickel Based Superalloy ◽  
Deformation Behaviors

scholarly journals Phase transformation and evolution of dislocation structure in the β phase of Ti-17 alloy during hot deformation

2020 ◽  
Vol 321 ◽  
pp. 13006
Author(s):  
K. Yamanaka ◽  
M. Mori ◽  
H. Matsumoto ◽  
A. Chiba
Keyword(s):  
Phase Transformation ◽  
Hot Deformation ◽  
Dynamic Recovery ◽  
Flow Behavior ◽  
True Strain ◽  
Recovery Process ◽  
Deformation Condition ◽  
Compression Tests ◽  
Β Phase ◽  
Dynamic Phase

The hot deformation behavior and microstructural evolution of Ti–5Al–2Sn–2Zr–4Mo–4Cr (Ti-17) alloy in the β-phase field were examined. Hot compression tests were conducted at temperatures ranging from 700 and 1100 °C and strain rates ranging from 10-3 to 1 s-1. The obtained true stress–true strain curves exhibited steady-state flow behavior at temperatures above the β-transus temperature (Tβ ~ 890 °C). The microstructural observations suggested that the dynamic recovery process represents a dominant mechanism for the β-phase of the alloy. In contrast, the flow softening was identified at 700 °C at a strain rate of 10–3 s–1. The formation of fine acicular α microstructures was noticed in such a deformation condition, indicating that dynamic phase transformation can occur in the metastable β-phase during hot deformation. Such a dynamic phase transformation also occurred preferentially at the initial β-grain boundaries as well as sub-boundaries that created within the βmatrix via dynamic recovery. The β-processing conditions were also examined by constructing processing maps based on the dynamic materials model (DMM).

scholarly journals High Temperature Behaviors of a Casting Nickel-Based Superalloy Used for 815 °C

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 716
Author(s):  
Jiangping Yu ◽  
Donghong Wang ◽  
Jingyang Chen ◽  
Changlin Yang ◽  
Xin Hao ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Peak Stress ◽  
Strain Rate Range ◽  
Deformation Condition ◽  
Strain Rates ◽  
Rate Range ◽  
Temperature Range ◽  
Nickel Based Superalloy ◽  
Deformation Behaviors

The hot deformation behaviors of the SJTU-1 alloy, the high-throughput scanned casting Nickel-based superalloy, was investigated by compression test in the temperature range of 900 to 1200 °C and strain rate range of 0.1–0.001 s−1. The hot processing map has been constructed with the instability zone. At the beginning of hot deformation, the flow stress moves rapidly to the peak value with the increased strain rates. Meanwhile, the peak stress is decreased with the increased temperature at the same strain rates. However, the peak stress shows the same tendency with the strain rates at the same temperature. The optimum hot deformation condition was determined in the temperature range of 1000–1075 °C, and the strain rate range of 0.005–0.1 s−1. The microstructure investigation indicates the strain rate significantly affects the characteristics of the microstructure. The deformation constitutive equation has also been discussed as well.

scholarly journals Hot Deformation Behaviors and Microstructure Evolution in a New PM Nickel-Base Superalloy

2011 ◽  
Vol 278 ◽  
pp. 411-416 ◽  
Author(s):  
Gao Feng Tian ◽  
Jin Wen Zou ◽  
Yu Wang ◽  
Wu Xiang Wang
Keyword(s):  
Activation Energy ◽  
Hot Deformation ◽  
Nickel Base Superalloy ◽  
Compression Tests ◽  
Working Process ◽  
Test Conditions ◽  
Deformation Behaviors ◽  
Nickel Base ◽  
Activation Energy Of Deformation ◽  
Base Superalloy

The hot deformation behaviors and the effect of flow stress on the microstructure were investigated for the as-HIPed and as-extruded materials in a new PM nickel-base superalloy. Under most test conditions, the as-extruded material exhibits superplastic flow because of grain growth corresponding to work hardening during deformation process, activation energy for deformation of which is 211 kJ/mol. However, activation energy of deformation for the as-HIPed material is 717 kJ/mol, because grain size is refined due to dynamic recrystallization, the reason being considered to be associated with the initial microstructure before the deformation. Based on the results of compression tests, two constitutive equations for the two materials were established using the mathematical regression; these will provide the valuable helps for predicting and controlling the deformed microstructure as well as optimizing hot-working process.

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