scholarly journals Dynamic Recrystallization and Hot-Working Characteristics of Ni-Based Alloy with Different Tungsten Content

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 298 ◽  
Author(s):  
Zhihua Gong ◽  
Hansheng Bao ◽  
Gang Yang
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Strain Rate Range ◽  
Hot Working ◽  
Recrystallization Temperature ◽  
Compression Tests ◽  
Stable Domain ◽  
Hyperbolic Sine ◽  
Complete Recrystallization

The hot deformation behavior of the GY200 Ni-based alloys with different tungsten (W) content were investigated by means of hot compression tests, microscopic observations, and processing maps at temperatures between 950 °C and 1200 °C, strain rate between 0.01 s−1 and 10 s−1 with strain of 0.9. The hyperbolic-sine type constitutive equations were established between peaks tress and deformation conditions through Z parameters, and for alloys with higher W content results in higher activation energy and complete recrystallization temperature. The hot-working maps were exploited based on the experimental data. The hot-working maps showed that the instability zone extended with increasing W content. The stable domain of alloys are located in the temperature range between 1025 °C and 1200 °C and strain rate range between 0.01 s−1 and 1 s−1, dominated by the dynamic recrystallization (DRX) microstructural evolution, suited for hot deformation. The cracking on the surface of the sample compressed at 950 °C was resulted from the tensile stress, while the fracture of the sample compressed at 1200 °C was triggered by the melting of grain boundaries.

scholarly journals Hot Deformation Behavior of Homogenized Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr Alloy via Hot Compression Tests

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2282 ◽  
Author(s):  
Zhimin Zhang ◽  
Zhaoming Yan ◽  
Yue Du ◽  
Guanshi Zhang ◽  
Jiaxuan Zhu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Strain Rate Range ◽  
Hot Compression ◽  
Test Machine ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

Mg-Gd-Y-Zn-Zr Mg alloys show excellent performance in high-end manufacturing due to its strength, hardness and corrosion resistance. However, the hot deformation and dynamic recrystallization (DRX) behaviors of Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr were not studied. For this article, hot compression behavior of homogenized high rare-earth (RE) content Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr (wt%) alloy was investigated by using the Gleeble-3500D thermo-simulation test machine under the temperature of 350–500 °C and the strain rate of 0.001–1 s−1. It was found that the high flow stress corresponded to the low temperature and high strain rate, which showed DRX steady state curve during the hot compression. The hot deformation average activation was 263.17 kJ/mol, which was obtained by the analysis of the hyperbolic constitutive equation and the Zener-Hollomon parameter. From observation of the microstructure, it was found that kink deformation of long period stacking ordered (LPSO) phase was one of the important coordination mechanisms of hot deformation at low temperature. The processing map with the strain of 0.5 was established under the basis of dynamic material model (DMM); it described two high power dissipation domains: one appearing in the temperature range of 370–440 °C and the strain rate range of 0.001–0.006 s−1, the other appearing in the temperature range of 465–500 °C and strain rate range of 0.001–0.05 s−1, in which dynamic recrystallization (DRX) mainly ocurred. The highest degree of DRX was 18% from the observation of the metallographic.

Critical Strain for the Initiation of Dynamic Recrystallization in a Ni-Fe Base Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 577-580
Author(s):  
Young Sang Na ◽  
Young Mok Rhyim ◽  
J.Y. Lee ◽  
Jae Ho Lee
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Critical Strain ◽  
Base Alloy ◽  
Strain Rate Range ◽  
Boundary Phase ◽  
Alloy 718 ◽  
Compression Tests ◽  
Temperature Range ◽  
Critical Strains

In order to quantitatively analyze the critical strain for the initiation of dynamic recrystallization in Ni-Fe-based Alloy 718, a series of uniaxial compression tests was conducted in the temperature range 927°C - 1066°C and the strain rate range 5 x 10-4s-1- 5 s-1with varying initial grain size. The critical strains were graphically determined based on one parameter approach and microscopically confirmed. The effect of γ'' (matrix-hardening phase) and δ (grain boundary phase)on the critical strain was simply discussed. The constitutive model for the critical strain of Alloy 718 was constructed using the experimental data obtained from the higher strain rate and the temperature range between 940°C and 1040°C.

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.

Characterization of Hot Deformation Behavior of Udimet720Li Superalloy Using Processing Map

2014 ◽  
Vol 887-888 ◽  
pp. 1161-1168
Author(s):  
Jian Guo Wang ◽  
Dong Liu ◽  
Tao Wang ◽  
Yan Hui Yang
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
High Strain ◽  
Flow Behavior ◽  
Strain Range ◽  
Peak Stress ◽  
Strain Rate Range ◽  
Hot Working ◽  
Compression Tests ◽  
Hollomon Parameter

The deformation behavior of a Udimet720Li superalloy under hot compression tests was characterized in the temperature range of 1060~1160°C and strain rate range of 0.001~20s-1. Processing maps were conducted at a series of strains to calculate the efficiency of hot working and to recognize the instability regions of the flow behavior. A Zener-Hollomon parameter is given to characterize the dependence of peak stress on temperature and strain rate. The efficiency of power dissipation of the Udimet720Li superalloy obtained in a strain range of 0.1~0.7 are essentially similar, which indicates that strain does not have a significant influence and the instability region shown in high strain and high strain rates at all temperatures. The regions for the full recrystallization can be divided by the dissolution beginning temperature of primary γ'which are the optimum hot working parameters.

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.

scholarly journals Constitutive Equation and Hot Processing Map of a Nitrogen-Bearing Martensitic Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1502
Author(s):  
Xiao Li ◽  
Lifeng Hou ◽  
Yinghui Wei ◽  
Zhengyan Wei
Keyword(s):  
Stainless Steel ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Martensitic Stainless Steel ◽  
True Strain ◽  
True Stress ◽  
Hot Working ◽  
Compression Tests

The hot deformation behavior of a nitrogen-bearing martensitic stainless steel was researched by the isothermal compression test in the temperature range of 950–1150 °C and strain rate range of 0.01–10 s−1 with a Gleeble-3800 thermal-mechanical simulating tester. A strain compensated sine-hyperbolic Arrhenius-type constitutive equation was developed to describe the relationship between true stress and deformation parameters such as temperature, strain rate and true strain. The hot deformation activation energy is calculated to be from 407 to 487 KJ mol−1. It is validated by the standard statistical parameters that the established constitutive equation can accurately predict the true stress. The processing maps at different true strains were constructed based on the dynamic material model (DMM) and the true stress data obtained from the hot compression tests. Two unstable regions which should be avoided during hot working were observed from the processing map. In addition, the optimum hot working parameters are located in the domain of 1000–1150 °C/0.1–1 s−1 with the peak power dissipation efficiency of 39.9%, in which complete dynamic recrystallization (DRX) occurs.

A Study on Dynamic Recrystallization Behaviours of AZ80 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 2847-2850
Author(s):  
Ming Yang ◽  
Yong Shun Yang ◽  
Dong Dong Yang
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Dimensionless Parameter ◽  
Strain Rate Range ◽  
Avrami Exponent ◽  
Compression Tests ◽  
Rate Range ◽  
Recrystallization Kinetics ◽  
Az80 Magnesium Alloy

Using the compression tests on a Gleeble-1500 thermo-mechanical simulator to study the dynamic recrystallization behaviours of AZ80 magnesium alloy in the temperature range of 593-683K and strain rate range of 0.01-10s-1. By the analysis of the dynamic recrystallization kinetics, the Avrami exponent (m) and the constant (k) have been determined, and they aren’t constant and depend on the dimensionless parameter(Z/A).

Constitutive Relationship and Critical Condition for Dynamic Recrystallization of Inconel 625 during Hot Deformation

2012 ◽  
Vol 538-541 ◽  
pp. 1240-1244 ◽  
Author(s):  
Sheng Li Guo ◽  
De Fu Li ◽  
Zhi Gang Wu
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Critical Condition ◽  
Strain Rate Range ◽  
Constitutive Relationship ◽  
Inconel 625 ◽  
Compression Tests ◽  
Order Polynomial ◽  
Strain Hardening Rate ◽  
Good Agreement

Hot compression tests of the commercial Inconel 625 were performed in the temperature range of 950 - 1200 °C and strain rate range of 0.01 - 10 s-1. The constitutive relationship and the critical condition for dynamic recrystallization of Inconel 625 were established. The influence of strain on the flow stress was investigated by considering the effect of the strain on material constants. It was found that a five-order polynomial was suitable to represent the influence of the strain. The stress-strain curves obtained by the proposed constitutive equation showed a good agreement with experimental results. It can be used for the analysis problem of hot forming processes.The critical condition for dynamic recrystallization was obtained by using strain hardening rate. The critical strain increased with temperature decreasing and strain rate increasing. The critical condition for dynamic recrystallization can be expressed as .

Hot Deformation and Processing Map of C919 Aluminum Alloy

2015 ◽  
Vol 816 ◽  
pp. 810-817
Author(s):  
Yong Biao Yang ◽  
Zhi Min Zhang ◽  
Xing Zhang
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Testing Machine ◽  
Strain Rate Range ◽  
Hot Compression ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests

The hot deformation behaviors of Aluminum alloy C919 were studied in the present investigation. The hot compression tests for C919 were carried out in the temperature range of 350°C~470°C and strain rates range of 0.001s-1~1s-1 using GLEEBLE-1500 thermal simulate testing machine. Optical microscopy (OM) was used for the microstructure characterization. The experimental results showed that the flow stress of C919 aluminum alloy decreased with increasing temperature and decreasing strain rates and the flow stress curves tended to increase at a strain rate of 1s-1 with increasing strain, while the flow stresses kept with increasing strain at lower strain rate. The alloys were more prone to dynamic recrystallization with decreasing strain rates during hot deformation. The hot compression behavior of C919 aluminum alloy can be described as hyperbolic sine function corrected Arrhenius relation. The processing maps for the alloy were built at a strain of 0.6. The instability deformation domain occurred at temperatures range from 350°C and 380°C and at a strain rate of 0.1-1s-1. Based on the processing maps and microstructure observations, the optimum hot-working parameters were determined to be at a temperature of 470°C in the strain rate range from 0.1-0.01s−1 for the C919 aluminum alloy.

scholarly journals Thermal Deformation Behavior of Ti-6Mo-5V-3Al-2Fe Alloy

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1245
Author(s):  
Lin Han ◽  
Haoyu Zhang ◽  
Jun Cheng ◽  
Ge Zhou ◽  
Chuan Wang ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Rate Sensitivity ◽  
Hot Working ◽  
Sensitivity Index ◽  
Strain Rate Sensitivity Index ◽  
Deformation Activation Energy ◽  
New Type

The Gleeble-3800 thermal simulation machine was used to perform hot compression experiments on a new type of β alloy, Ti-6Mo-5V-3Al-2Fe (wt.%), at temperatures of 700–900 °C, strain rates of 5 × 10−1 to 5 × 10−4 s−1, and total strain of 0.7. Transmission and EBSD techniques were used to observe the microstructure. The results show that the deformation activation energy of the alloy was 356.719 KJ/mol, and dynamic recrystallization occurred during the hot deformation. The higher the deformation temperature was, the more obvious the dislocations that occurred and the more sufficient the dynamic recrystallization that occurred, but the effect of strain rate was the opposite. When the deformation temperature was higher than the phase transition point, the recrystallized grains clearly grew up. The calculated strain rate sensitivity index of the alloy was 0.14–0.29. The constitutive equation of hot deformation of Ti-6Mo-5V-3Al-2Fe alloy was established by using the Arrhenius hyperbolic sine equation. The dynamic DMM hot working diagram with the strain of 0.7 was constructed. The relatively good hot working area of the alloy was determined to be the deformation temperature of 700–720 °C and 0.0041–0.0005 s−1.

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