Deformation Behavior and Dynamic Recrystallization of As-Cast Mg-Y-Nd-Gd-Zr Alloy: A Study with Processing Map

2009 ◽  
Vol 610-613 ◽  
pp. 815-821 ◽  
Author(s):  
Xin Zhao ◽  
Kui Zhang ◽  
Xing Gang Li ◽  
Yong Jun Li ◽  
Kang Zhang ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Processing Map ◽  
Flow Behavior ◽  
Material Model ◽  
Dissipation Factor ◽  
Power Exponent ◽  
Strain Rates ◽  
Mechanical Working ◽  
Dynamic Material Model

The characteristic of dynamic recrystallization (DRX) in Mg-Y-Nd-Gd-Zr magnesium alloy had been investigated by compression test at temperatures between 523 and 723K and the strain rates ranging from 0.002 to 1s-1with maximum strain of 0.693. The flow behavior was described by a power exponent function. Processing map of this alloy was established on the basis of dynamic material model. Microstructure observations suggested that the peak value of dissipation factor was 0.36 at the temperature of 673K and the strain rate of 1s-1. The map exhibits flow instabilities as two domains, one is at the lower temperatures but higher strain rates, and the other is at higher temperatures and lower strains.The region at an intermediate temperature and a high strain rate is the region of the optimal mechanical working properties.

Hot Simulation Compression of In Situ TiBw/Ti6Al4V Composites with Novel Network Microstructure

2013 ◽  
Vol 762 ◽  
pp. 382-386
Author(s):  
Lu Jun Huang ◽  
Yu Zi Zhang ◽  
Lin Geng
Keyword(s):  
Processing Map ◽  
Peak Flow ◽  
Flow Instability ◽  
Material Model ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Compression Behavior ◽  
Dynamic Material Model ◽  
Network Microstructure

The hot compression behavior of in situ TiB whiskers reinforced Ti6Al4V (TiBw/Ti6Al4V) composites with a novel network microstructure is investigated in the temperature range of 900-1100°C and strain rate range of 0.001-10 s-1. The results show that all the stress-strain curves of the composites display peak flow, softening and steady-state. Moreover, the peak flow stress decreases with increasing temperatures and decreasing strain rates. Processing map of the composite is constructed using the dynamic material model (DMM). Dynamic recrystallization (DRX) of α phase is observed in the deformation region corresponding with peak efficiency of the processing map. However, the flow instability region ranged from 900 to 1100°C at strain rates higher than 1.0 s-1should be avoided.

scholarly journals Hot Workability of Ultra-Supercritical Rotor Steel Using a 3-D Processing Map Based on the Dynamic Material Model

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4118
Author(s):  
Xuewen Chen ◽  
Yuqing Du ◽  
Tingting Lian ◽  
Kexue Du ◽  
Tao Huang
Keyword(s):  
Finite Element ◽  
Alloy Steel ◽  
Thermal Processing ◽  
Processing Map ◽  
Three Dimensional ◽  
Material Model ◽  
Strain Rates ◽  
Rotor Steel ◽  
Dynamic Material Model ◽  
Finite Element Software

As a new-type of ultra-supercritical HI-IP rotor steel, X12CrMoWVNbN10-1-1 alloy steel has excellent integrative performance, which can effectively improve the power generation efficiency of the generator set. In this paper, uniaxial thermal compression tests were carried out over a temperature range of 950–1200 °C and strain rates of 0.05–5 s−1 with a Gleeble-1500D thermal simulation testing machine. Moreover, based on hot compression experimental data and the theory of processing diagrams, in combination with the dynamic material model, a three-dimensional (3-D) thermal processing map considering the effect of strain was constructed. It was concluded that optimum thermal deformation conditions were as follows: the temperature range of 1150–1200 °C, the strain rate range of 0.05–0.634 s−1. Through secondary development of the finite element (FE) software FORGE®, three-dimensional thermal processing map data were integrated into finite element software FORGE®. The distributions of instability coefficient and power dissipation coefficient were obtained over various strain rates and temperatures of the Ø 8 × 12 mm cylinder specimen by using finite element simulation. It is shown that simulation results are consistent with the microstructure photos. The method proposed in this paper, which integrates the three-dimensional processing map into the finite element software FORGE® (Forge NxT 2.1, Transvalor, Nice, France), can effectively predict the formability of X12CrMoWVNbN10-1-1 alloy steel.

Compressive Deformation of ZK60 Magnesium Alloy at Elevated Temperature

2007 ◽  
Vol 353-358 ◽  
pp. 631-634 ◽  
Author(s):  
Chun Yan Wang ◽  
Kun Wu ◽  
Ming Yi Zheng
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Flow Behavior ◽  
Testing Machine ◽  
Mechanical Twinning ◽  
Dislocation Slip ◽  
Strain Rates ◽  
Lower Temperature ◽  
Zk60 Magnesium Alloy

The high temperature compressive tests of squeeze casting ZK60 magnesium alloy with temperatures of 573-723K and strain rate in the range of 0.001-1s-1 were performed on Gleeble-1500D thermal simulator testing machine. Optical microscopy was performed to elaborate on the dynamic recrystallization (DRX) grain growth. TEM findings indicate that mechanical twinning, dislocation slip, and dynamic recrystallization are the materials typical deformation features. Variations of flow behavior with deformation temperature as well as strain rate were analyzed. Analysis of the flow behavior and microstructure observations indicated that flow localization was observed at lower temperature and higher strain rates, which should be avoided during mechanical processing. Dynamic recrystallization occurred at higher temperature and moderate strain rates, which improved the ductility of the material. The optimum hot working conditions for ZK60 alloy were suggested.

Flow Behavior and Microstructural Evolution of a 7039 Aluminum Alloy during Hot Deformation

2011 ◽  
Vol 239-242 ◽  
pp. 2395-2398 ◽  
Author(s):  
Hui Zhong Li ◽  
Xiao Peng Liang ◽  
Min Song ◽  
Min Zeng
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Microstructural Evolution ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Flow Behavior ◽  
Thermal Simulation ◽  
Strain Rates

The flow behavior of a 7039 aluminum alloy and the corresponding microstructural evolution during hot deformation were studied by Gleeble-1500 thermal simulation tests, EBSD and TEM observations with temperatures ranging from 300 °C to 500 °C under strain rates from 0.01 s-1 to 10 s-1. It has been shown that the flow stress increases with the decrease in the deformation temperature and increase in the strain rate. The degree of dynamic recrystallization (DRX) increases with the increase in the deformation temperature and strain rate in 7039 aluminum alloy. The complete dynamic recrystallization occurs at 500 °C with a strain rate of 10 s-1.

Hot Deformation Behavior of TiNiFe Shape Memory Alloy: A Study with Processing Map

2013 ◽  
Vol 631-632 ◽  
pp. 371-376 ◽  
Author(s):  
X.Q. Yin ◽  
S.J. Wang ◽  
Y.F. Li ◽  
B.D. Gao ◽  
X.Y. Kang ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Strain Rate ◽  
Shape Memory ◽  
Deformation Temperature ◽  
Processing Map ◽  
Material Model ◽  
Dynamic Material Model ◽  
Back Scattering ◽  
Instability Regions ◽  
Gleeble 3500

Isothermal compression of the TiNiFe shape memory alloy has been carried out on a Gleeble-3500 thermal simulation machine at the deformation temperature ranging from 1023K to 1323K, the strain rate ranging from 0.01s-1 to 10s-1 with total strain of 0.8. On the basis of dynamic material model, the processing map is established with two instability regions and a desirable domain which demonstrate optimum hot working conditions within the experimental parameters. By means of Electron Back Scattering Diffraction, we come to the conclusion that both dynamic recovery and dynamic recrystallization exist in the desirable domain with deformation temperature ranging 1123 K and strain rate 0.1s-1. The uneven deformation exits in the low deformation temperature with high strain rate area, such as 1023 K and10 s-1. And with 1323K and 0.01s-1 strain rate, the recrystallized grains are abnormal grow up.

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.

scholarly journals HOT DEFORMATION BEHAVIOR AND PROCESSING MAP OF A Mg-Gd-Y-Zn-Zr ALLOY

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Zhaoming Yan ◽  
Jiaxuan Zhu ◽  
Zhimin Zhang ◽  
Qiang Wang ◽  
Yong Xue
Keyword(s):  
Strain Rate ◽  
Flow Behavior ◽  
Type Equation ◽  
Peak Stress ◽  
Material Model ◽  
Processing Parameters ◽  
Compression Tests ◽  
Hollomon Parameter ◽  
Dynamic Material Model ◽  
Deformation Behaviors

Compression tests of a Mg-13Gd-4Y-2Zn-0.5Zr alloy were carried out on a Gleeble-1500D thermo-mechanical simulator within a temperature range of 420–500 °C and strain rate of 0.001–5 s–1 so that the corresponding flow behavior was investigated. The Zener-Hollomon parameter Z was used in a hyperbolic-sine-type equation to express the relationships between the peak stress, deformation temperature and strain rate. Work hardening, dynamic recovery and dynamic recrystallization were the main characteristics affecting the plastic-deformation behaviors. The activation energy Q was calculated to be 208.2 kJ/mol and processing maps at strains of 0.3, 0.5 and 0.7 were generated based on a dynamic material model. The optimum processing parameters were obtained with a power-dissipation analysis.

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.

Constitutive Modeling for Elevated Temperature Flow Behavior of ZHMn34-2-2-1 Manganese Brass

2017 ◽  
Vol 872 ◽  
pp. 30-37
Author(s):  
Meng Han Wang ◽  
Kang Wei ◽  
Xiao Juan Li
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Flow Behavior ◽  
Peak Stress ◽  
Strain Rates ◽  
Hollomon Parameter ◽  
Prediction Ability ◽  
Absolute Relative Error ◽  
Deformation Behaviors ◽  
State Stress

The hot compressive deformation behaviors of ZHMn34-2-2-1 manganese brass are investigated on Thermecmastor-Z thermal simulator over wide processing domain of temperatures (923K-1073K) and strain rates (0.01s-1-10s-1). The true stress-strain curves exhibit a single peak stress, after which the stress monotonously decreases until a steady state stress occurs, indicating a typical dynamic recrystallization. A revised constitutive model coupling flow stress with strain, strain rate and deformation temperature is established with the material constants expressed by polynomial fitting of strain. Moreover, better prediction ability of the constitutive model is achieved by implementation of a simple approach for modified the Zener-Hollomon parameter considering the compensation of strain rate and temperature increment. By comparing the predicted and experimented values, the correlation coefficient and mean absolute relative error are 0.997 and 2.363%, respectively. The quantitative statistical results indicate that the proposed constitutive model can precisely characterize the hot deformation behavior of ZHMn34-2-2-1 manganese brass.

scholarly journals Hot Deformation Behavior of a Ni-Based Superalloy with Suppressed Precipitation

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 605
Author(s):  
Franco Lizzi ◽  
Kashyap Pradeep ◽  
Aleksandar Stanojevic ◽  
Silvana Sommadossi ◽  
Maria Cecilia Poletti
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Strain Rates ◽  
Compression Tests ◽  
Deformation Bands ◽  
Stress Softening ◽  
Relative Stress ◽  
The Matrix ◽  
Thermomechanical Processes

Inconel®718 is a well-known nickel-based super-alloy used for high-temperature applications after thermomechanical processes followed by heat treatments. This work describes the evolution of the microstructure and the stresses during hot deformation of a prototype alloy named IN718WP produced by powder metallurgy with similar chemical composition to the matrix of Inconel®718. Compression tests were performed by the thermomechanical simulator Gleeble®3800 in a temperature range from 900 to 1025 °C, and strain rates scaled from 0.001 to 10 s−1. Flow curves of IN718WP showed similar features to those of Inconel®718. The relative stress softening of the IN718WP was comparable to standard alloy Inconel®718 for the highest strain rates. Large stress softening at low strain rates may be related to two phenomena: the fast recrystallization rate, and the coarsening of micropores driven by diffusion. Dynamic recrystallization grade and grain size were quantified using metallography. The recrystallization grade increased as the strain rate decreased, although showed less dependency on the temperature. Dynamic recrystallization occurred after the formation of deformation bands at strain rates above 0.1 s−1 and after the formation of subgrains when deforming at low strain rates. Recrystallized grains had a large number of sigma 3 boundaries, and their percentage increased with strain rate and temperature. The calculated apparent activation energy and strain rate exponent value were similar to those found for Inconel®718 when deforming above the solvus temperature.

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