Processing Map and Microstructural Evolution of Isothermal Compressed an Al-Mg-Si-Cu-Zn Alloy

2016 ◽  
Vol 877 ◽  
pp. 575-580
Author(s):  
Li Zhen Yan ◽  
Yong An Zhang ◽  
Bai Qing Xiong ◽  
Zhi Hui Li ◽  
Xi Wu Li ◽  
...  
Keyword(s):  
Strain Rate ◽  
Microstructural Evolution ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Processing Map ◽  
Flow Behavior ◽  
Processing Condition ◽  
Electron Back Scatter Diffraction ◽  
Microstructure Observation ◽  
Hot Rolled

The hot deformation behavior of an Al-0.92Mg-0.78Si-0.20Cu-0.60Zn alloy was studied by isothermal compression in the temperature range from 350 to 500 oC with strain rates of 0.01-10s-1 on Gleeble-1500 thermo-mechanical simulator. The microstructural evolution during hot deformation was investigated by electron back-scatter diffraction (EBSD). The results show that the strain rate and deformation temperature have significant influence on flow behavior, and the flow stress increases with increasing strain rate and decreasing deformation temperature. Processing map at the strain of 0.7 is obtained and exhibits three peak efficiency domains (380-420 oC at 0.01s-1, 480-500 oC at 0.01s-1 and 450-500 oC at 0.1-0.32s-1). According to the processing map and microstructure observation, the optimized processing condition of hot deformation for the alloy is at 450-500 oC and strain rate of 0.1-0.32s-1. The homogenized ingot is hot rolled at 480 oC with a strain rate of 0.1s-1 based on optimized deformation parameters. The fraction of high-angle grain boundary is 35.2%, which is in accord with microstructure after hot deformed at 500 oC with a strain rate of 0.1s-1.

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.

Effect of Hot Deformation Parameters on Flow Behavior and Microstructure of Ti-6Al-4V-0.2O Alloy

2017 ◽  
Vol 898 ◽  
pp. 137-143
Author(s):  
Lin Xiang ◽  
Bin Tang ◽  
Hong Chao Kou ◽  
Jie Shao ◽  
Jin Shan Li
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Dynamic Recovery ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Strain Rates ◽  
Compression Tests ◽  
Height Reduction ◽  
Deformation Parameters

Isothermal compression tests were conducted to investigate the effect of hot deformation parameters on flow behavior and microstructure of Ti-6Al-4V-0.2O alloy. The experimental results show that the strain rate and height reduction have little effect on the volume fraction of primary α at a deformation temperature of 860 ̊C. At a deformation temperature of 940 ̊C, the volume fraction of primary α at a high strain rate (10s-1) is about 10% less than that at low strain rates (0.01s-1~1s-1). It may be one of the reasons for the significantly discontinuous yielding phenomenon. Another reason is that the dislocation density decreased suddenly due to the dynamic recovery. With the increasing strain rate and the decreasing deformation temperature, the volume fraction of irregular secondary α increases and lamellar secondary α decreases. And with height reduction increasing, the irregular secondary α increases firstly and then tends to be steady because of dynamic recovery and recrystallization.

scholarly journals Characterization of Hot Deformation Behavior and Dislocation Structure Evolution of an Advanced Nickel-Based Superalloy

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 920 ◽  
Author(s):  
Zhihao Yao ◽  
Hongying Wang ◽  
Jianxin Dong ◽  
Jinglin Wang ◽  
He Jiang ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Flow Instability ◽  
Processing Condition ◽  
Constitutive Relationship ◽  
Structure Evolution ◽  
Hot Deformation Behavior

The hot deformation behavior of an advanced nickel-based Haynes282 superalloy was systematically investigated employing isothermal compression tests in the sub-solvus and super-solvus temperature with various strain rates. The influence of deformation temperature and strain rate on the microstructure was studied by transmission electron microscope. The results reveal that the interaction between work hardening and dynamic softening did not reach equilibrium under lower deformation temperature and higher strain rate. The active energy of alloy is around 537.12 kJ/mol and its hot deformation constitutive relationship equation was expressed. According to the processing map and microstructure observations, two unsafe flow instability domains should be avoided. The optimum hot processing condition for homogeneous and fine dynamic recrystallization grains are obtained. TEM micrograph observations indicated that deformation temperature and strain rate affected recrystallization by affecting the evolution of dislocation substructures within the alloy. The nucleation and growth of DRX grains can be promoted by the relatively high deformation temperature and low strain rate. The main mechanism of dynamic recrystallization nucleation preferred to discontinuous dynamic recrystallization and the typical feature of discontinuous dynamic recrystallization showed grain boundary migration nucleation. The findings improve the understanding of hot deformation behavior and dislocation substructures evolution of the superalloy, which benefits the accurate control of microstructures of nickel-based superalloys, and tailors the properties of final components used in the land-based gas turbine.

Study of Hot Deformation Behavior in GH4169 Superalloy

2013 ◽  
Vol 712-715 ◽  
pp. 658-661 ◽  
Author(s):  
Dong Xu Wen ◽  
Y.C. Lin ◽  
Ming Song Chen
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Work Hardening ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Flow Behavior ◽  
Peak Stress ◽  
Processing Parameters ◽  
Initial Increase ◽  
Gh4169 Superalloy

In order to study the workability and optimize hot forming processing parameters for GH4169 superalloy, the hot deformation behaviors are investigated. The results show that the flow stress strongly depends on the strain rate, deformation temperature and strain. With the increase of strain rates and the decrease of deformation temperature, the flow stress increases. The flow stress exhibits an initial increase with the strain until a peak stress value, showing a obvious work hardening. After the peak stress, increasing strain results in the decrease of stress, indicating a dynamic flow softening. A revised constitutive equation incorporating the effects of temperature, strain rate and work-hardening rate of the material is established by compensation of strain. A good agreement between the measured and predicted results shows that the established model can give an accurate prediction of the flow behavior of GH4169 superalloy.

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.

Constitutive Modeling for Flow Behavior of As-Cast 1026 Carbon Steel Under Hot Compression Experiments

2015 ◽  
Author(s):  
Li Ju ◽  
Yongtang Li ◽  
Jianhua Fu ◽  
Bufang Lei ◽  
Huiping Qi
Keyword(s):  
Flow Stress ◽  
Carbon Steel ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Flow Behavior ◽  
Hot Compression ◽  
Stress Index ◽  
Heating Process

Nowadays, modern casting theories and technologies have got marked progress in reducing steel casting’s defects, such as shrinkages, cracks, porosities, and segregations, which make it possible to manufacture industrial parts with casting instead of forging billet. Compared with the traditional technology, the new method will have many obvious advantages in reducing heating times and discharge, saving materials and energy, and improving productivity. In order to produce parts with sound mechanical properties by employing the new technology, it is important to probe the flow behavior of as-cast carbon steel under hot deformation for premium controlling processing parameters, reasonable planning procedures and a reliable constitutive equation for precise simulation. In this paper, high temperature flow behavior of as-cast 1026 carbon steel is investigated by conducting hot compression experiments on Gleeble-3500 simulator in the temperature range from 1 173 K to 1 473 K at an interval of 100 K and the stain rate range from 0.1 s−1 to 2.0 s−1. The relationships of deformation parameters (temperature, strain rate) with material’s flow behavior are found. The deformation activation energy and the stress index are worked out and the mathematical model of the flow stress under hot deformation is established by means of the liner regression analysis of true stress-strain data. Meanwhile, the effect of initial grain sizes on flow behavior of as-cast 1026 steel is also studied by compressing samples cooled to 1 173 K from 1 273 K, 1 373 K and 1 473 K respectively. The experimental results reveal that strain hardening and flow softening mainly characterize the flow behavior. It is also found that with the increase of deformation, the flow stress first increases rapidly, then reaches the peak slowly, after that it begins to decrease and finally comes to a steady value. At the temperature of 1 173 K, material’s softening is not apparent even if the strain rate is increased, while at the strain rate of 2 s−1, it is also not apparent even when the deformation temperature is raised to 1 473 K, so the final forging temperature is supposed to be about 1 173 K and the maximum stain rates should be below 2 s−1. In addition, at the same deformation temperature and strain rate, the more refined initial grain, the easier material dynamically recrystallizes and the lower the steady stress is. Therefore, the heating process of material is expected to be tightly controlled. The maximum error of flow stress between the model predictions and actual results is only 5.90%. The good agreement signifies the applicability of this method as a general constitutive equation in hot deformation studies.

Hot Deformation Behavior and Microstructure Evolution of GH625 Superalloy Tube during Extrusion Process

2011 ◽  
Vol 291-294 ◽  
pp. 640-644
Author(s):  
Qing Miao Guo ◽  
De Fu Li ◽  
Sheng Li Guo ◽  
Guo Ling Xie
Keyword(s):  
Strain Rate ◽  
Microstructure Evolution ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Flow Behavior ◽  
Outer Wall ◽  
Extrusion Process ◽  
Compression Tests ◽  
Hot Deformation Behavior

Flow behavior and microstructures of GH625 superalloy were investigated by hot compression tests. Then the GH625 superalloy tube was hot extruded according to the hot deformation behavior, and the microstructures of different position of extruded tube was also analyzed. The results show that the actual deformation temperature of the specimen deformed at a strain rate of 10.0s-1 is higher than the preset temperature, resulting in a deformation thermal effect. Thus, the microstructure evolution of GH625 superalloy is controlled both by the strain rate and deformation temperature. It is also found that the GH625 superalloy tube can be successfully fabricated with a stable extrusion speed of 40 mm·s-1, extrusion ratio of 4.1 and preheating temperature of 1200°C. The microstructure of extruded tube was obviously fined due to the occurrence of dynamic recrystallization(DRX). Different degrees of DRX were observed in outer wall, center and inner wall of the tube, which is similar to that in the head, middle and tail of the tube. An extruded tube containing fully DRX grains can be obtained by cutting the head and tail of the tube, and machining a small amount of the inner wall.

Hot Deformation Behavior of Al-Zn-Mg-Zr Alloy with Trace Amounts of Sc

2013 ◽  
Vol 634-638 ◽  
pp. 1740-1745
Author(s):  
Bo Li ◽  
Qing Lin Pan ◽  
Chen Li ◽  
Yan Fang Song ◽  
Zhi Ye Zhang
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Flow Behavior ◽  
Temperature Deformation ◽  
Simulation Test ◽  
Hollomon Parameter ◽  
Deformation Activation Energy ◽  
Zr Alloy

The flow behavior of Al-Zn-Mg-Sc-Zr alloy during hot compression deformation was studied by thermal simulation test at strain rate of 0.001 to 10s-1 and deformation temperature of 340 to 500°C on the Gleeble-1500 thermal mechanical simulator. The results show that the flow stress increases with increasing strain rate, and decreases with increasing deformation temperature. The flow stress of the alloy during the elevated temperature deformation can be represented by a Zener-Hollomon parameter with the inclusion of the Arrhenius term. The values of A, n, α in the analytical expression of flow stress are fitted to be 1.49×1010s−1, 7.504 and 0.0114MPa−1, respectively. The hot deformation activation energy of the alloy during hot deformation is 150.25kJ/mol.

scholarly journals HIGH-TEMPERATURE DEFORMATION BEHAVIOR AND HOT-PROCESSING MAP OF 25CrMo4 AXLE STEEL BASED ON FRICTION CORRECTION

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Keran Liu ◽  
Yuanming Huo ◽  
Tao He ◽  
Cunlong Huo ◽  
Changyuan Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Process Parameters ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Deformation Process ◽  
Flow Behavior ◽  
Temperature Deformation ◽  
Flow Curves

The deformation behavior and microstructure of 25CrMo4 axle steel was systematically investigated by thermal compression deformation. The hot-compression test of a 25CrMo4 axle steel sample was carried out on a Gleeble-3800 thermal mechanical simulation tester. The flow behavior of the alloy was studied at the deformation temperature (900–1200 °C), strain rates (0.01; 0.1; 1.0) s–1 and the maximum deformation of 60 %. The flow curves under different deformation conditions were obtained, and the effects of the deformation temperature and strain rate on the appearance of the flow curves are discussed. The true stress-strain curve obtained by experiment is modified by friction. Based on the corrected experimental data, the activation energy determined by the regression analysis was Q = 311 kJ/mol, and the constitutive model was constructed. The high-temperature flow behavior of the 25CrMo4 axle steel was described by the Zener-Hollomon parameter. The optimum hot-deformation process parameters were determined based on the hot processing maps, followed by the analysis of the microstructure characteristics of the alloys under optimum hot working. The results show that the suitable hot-deformation process parameters of the alloy are as follows: deformation temperature is 1050–1200 °C, and strain rate is 0.01 s–1 to 0.14 s–1.

Sign in / Sign up

Export Citation Format

Share Document