Material Constants of Ferritic Spheroidal Cast Iron during Hot Deformation

2008 ◽  
Vol 575-578 ◽  
pp. 164-168 ◽  
Author(s):  
Xin Zhao
Keyword(s):  
Cast Iron ◽  
Strain Rate ◽  
Hot Deformation ◽  
Flow Curves ◽  
Material Constants ◽  
Thermally Activated ◽  
Straight Line ◽  
Deformation Behaviors ◽  
Gleeble 3500 ◽  
Joint Laboratory

The hot deformation behaviors of a ferritic spheroidal cast iron (FSCI) have been investigated by compression testing on a Gleeble 3500 machine of the DSI-YSU Joint Laboratory. The temperature rang was from 1073K to 1273K and strain rate from 10-3 to 1 s-1. The total true stain was 0.7. The result shows that the flow curves obtained are typical of dynamic recrystallization processes. The plots of either the natural logarithms of the corresponding temperature or the natural logarithms of strain rate against the hyperbolic of flow stresses satisfy straight line relationships over the experimental data, indicating that the hot compression of the FSCI is thermally activated. The material constants, including activation energy 0H as 240.8 kJ/mol, stress-level coefficient α as 1.352×10-8 Pa-1, stress exponential n as 3.9937, structural factor A as 5.64×108 s-1, are derived .

Constitutive Characteristic of Hot Deformation for Spray Formed Superalloy GH738

2013 ◽  
Vol 747-748 ◽  
pp. 569-574 ◽  
Author(s):  
Yue Wang ◽  
Zhou Li ◽  
Wen Yong Xu ◽  
Hua Yuan ◽  
Na Liu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Flow Curves ◽  
Deformation Activation Energy ◽  
Deformation Behaviors ◽  
Gleeble 3500 ◽  
Equiaxed Grains

The hot deformation behaviors of spray formed superalloy GH738 were investigated by using of Gleeble-3500 simulator in the temperature range of 950~1200, with a strain rate of 0.13~6.5s-1 and reduction of 50%. The corresponding flow curves were determined and hot deformed microstructures were observed. The results showed that the flow stress decreased with increasing deformation temperature or decreasing strain rate. A full dynamic recrystallization microstructures with fine-equiaxed grains were obtained at the temperature of 1100~1150 and strain rate of 2.6~6.5s-1. The hot deformation activation energy Q was 580.81kJ.mol-1, and the constitutive equation was derived by means of linear regression.

Hot Deformation Characteristics of Spray Formed Nickel Based P/M Superalloy

2014 ◽  
Vol 788 ◽  
pp. 565-568
Author(s):  
Na Liu ◽  
Z. Li ◽  
G.Q. Zhang ◽  
H. Yuan ◽  
W.Y. Xu ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Compression Test ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
True Strain ◽  
Spray Forming ◽  
Solution Temperature ◽  
Flow Curves ◽  
Gleeble 3500

The hot deformation behavior of a nickel based P/M superalloy by spray forming and hot isostaticpressingwas investigated by isothermal compression test at Gleeble 3500 thermal mechanical simulator. The compression test was performed in the temperature ranging from 1025°C to 1150°C and in the strain rate ranging from 10-1/s to 10-3/s. The results show that the flow curves of true stress and true strain exhibit typical dynamic recrystallization and dynamic recovery. Compression temperature and strain rate have a strong effect on the dynamic recrystallization grain refinement.With higher strain rate the refined dynamic recrystallizationmicrostructure can be obtained at deformation temperature lower thanγ′solution temperature. Grain coarsening occurs at the deformation temperature close to γ′solution temperature, and the grain grows up obviously with decreasing strain rate.

scholarly journals Hot Compression Deformation and Activation Energy of Nanohybrid-Reinforced AZ80 Magnesium Matrix Composite

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 119 ◽  
Author(s):  
Houyi Li ◽  
Lingling Fan ◽  
Mingyang Zhou ◽  
Youlong Zhou ◽  
Kuan Jiang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Strain Rate ◽  
Matrix Composite ◽  
Hot Deformation ◽  
Strain Rates ◽  
Magnesium Matrix ◽  
Deformation Activation Energy ◽  
Deformation Behaviors ◽  
Carbon Nano Tubes ◽  
Deformation Test

The hot deformation test of the nano silicon carbide (nano-SiC) and carbon nano tubes (CNT) hybrid-reinforced AZ80 matrix composite was performed at compression temperatures of 300–450 °C and strain rates of 0.0001–1 s−1. It could be observed that the flow stress of the nanocomposite rose with the reduction of deformation temperature and the increase of strain rate. The hot deformation behaviors of the composite could be described by the sine-hyperbolic Arrhenius equation, and deformation activation energy (Q) was calculated to be 157.8 kJ/mol. The Q values of the extruded nanohybrid/AZ80 composite in this study and other similar studies on extruded AZ80 alloys were compared in order to analyze the effect of the addition of reinforcement, and the effects of deformation conditions on activation energy were analyzed. Finally, the compression microstructure in an unstable condition was carefully analyzed, and results indicated that the phenomenon of local instability was easy to occur at the compression specimen of the nanohybrid/AZ80 composite under deformation conditions of low temperature with high strain rate (300 °C, 0.1–0.01 s−1), and high temperature with low strain rate (450 °C, 0.0001 s−1).

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 Resistance of an AA5083 Alloy under High Strain Rate

2014 ◽  
Vol 626 ◽  
pp. 553-560
Author(s):  
Shi Rong Chen ◽  
Chung Yung Wu ◽  
Yi Liang Ou ◽  
Yen Liang Yeh
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Hot Deformation ◽  
High Strain ◽  
Load Cell ◽  
Deformation Resistance ◽  
Strain Rates ◽  
Flow Curves ◽  
Aa5083 Alloy ◽  
Temperature Strain

Axisymmetric compression tests using Gleeble 3800 simulator were carried out to investigate hot deformation behaviors of an AA5083 alloy under high strain rate conditions. Sharp temperature rise and load cell ringing characterized by severely vibrational load responses were encountered at strain rates higher than 20 s-1 and sample buckling occurred at low temperatures. The load cell ringing was corrected using a moving average method with a two-way filtering operation to correct phase distortion. Isothermal flow curves were obtained by fitting the instantaneous temperatures into a binomial function, while buckling was correlated with sample height and Young’s modulus. After the corrections, hyperbolic sine equation was successfully used to extend from the hot tensile data having strain rates lower than 3 s-1 to 100 s-1. Quantitative analyses were accordingly made over the effects of temperature, strain rate and work hardening behavior on the flow curves. The previous constitutive equation in form of temperature, strain and strain rate was modified to predict the hot deformation resistance of the AA5083 alloy at temperatures of 250-450oC under the high strain rate operations.

Study on Hot Deformation Behavior of 97# High Strength Rod

2012 ◽  
Vol 159 ◽  
pp. 322-325
Author(s):  
Hong Bin Li ◽  
Fang Fang
Keyword(s):  
Hot Deformation ◽  
Deformation Behavior ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
High Strength ◽  
Avrami Equation ◽  
Recrystallization Process ◽  
Hot Deformation Behavior ◽  
Deformation Behaviors ◽  
Gleeble 3500

the hot deformation behaviors of 97# High Strength Rod was investigated through double-hit compression experiments using Gleeble 3500 thermal-mechanical similar within the temperature range of 850~1100°C, the strain rate of 5 s-1 and the interval range of 1-100s, the softening fractiong at different pass interval and deforming temperature was determined and analyzed. The results show that when pass intervals is the same, as deformation temperature increase, the volume fraction of static recrystallization of 97# High Strength Rod increases and the recrystallization process is enchanced. Activation energy of austenite static recrystallization of 97# High Strength Rod is 100.476 kJ/mol. The kinetic equation of static recrystallization of 97# High Strength Rod by avrami equation wan obtained.

Modeling the Hot Deformation Behaviors of As-Extruded 7075 Aluminum Alloy by an Artificial Neural Network with Back-Propagation Algorithm

2017 ◽  
Vol 36 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Guo-zheng Quan ◽  
Zhen-yu Zou ◽  
Tong Wang ◽  
Bo Liu ◽  
Jun-chao Li
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Aluminum Alloy ◽  
Strain Rate ◽  
Hot Deformation ◽  
Back Propagation ◽  
Bp Algorithm ◽  
7075 Aluminum Alloy ◽  
Ann Model ◽  
Deformation Behaviors

AbstractIn order to investigate the hot deformation behaviors of as-extruded 7075 aluminum alloy, the isothermal compressive tests were conducted at the temperatures of 573, 623, 673 and 723 K and the strain rates of 0.01, 0.1, 1 and 10 s−1 on a Gleeble 1500 thermo-mechanical simulator. The flow behaviors showing complex characteristics are sensitive to strain, strain rate and temperature. The effects of strain, temperature and strain rate on flow stress were analyzed and dynamic recrystallization (DRX)-type softening characteristics of the flow behaviors with single peak were identified. An artificial neural network (ANN) with back-propagation (BP) algorithm was developed to deal with the complex deformation behavior characteristics based on the experimental data. The performance of ANN model has been evaluated in terms of correlation coefficient (R) and average absolute relative error (AARE). A comparative study on Arrhenius-type constitutive equation and ANN model for as-extruded 7075 aluminum alloy was conducted. Finally, the ANN model was successfully applied to the development of processing map and implanted into finite element simulation. The results have sufficiently articulated that the well-trained ANN model with BP algorithm has excellent capability to deal with the complex flow behaviors of as-extruded 7075 aluminum alloy and has great application potentiality in hot deformation processes.

Study on Hot Deformation Behavior of a New Titanium Alloy

2014 ◽  
Vol 644-650 ◽  
pp. 4872-4875
Author(s):  
Qun Hui Zheng ◽  
Ke Lu Wang ◽  
Shi Qiang Lu
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Hot Deformation ◽  
Constant Strain Rate ◽  
Strain Curve ◽  
Constitutive Relationship ◽  
Alloy Sample ◽  
Two Phase ◽  
Data Points ◽  
Gleeble 3500

Two-phase titanium alloy sample which initial microstructure is equiaxed have been tested by the Gleeble-3500 thermo-analogue machine with the isothermal and constant strain rate, the constitutive relationship of the titanium alloy was constructed by analyzing true stress-strain curve under different hot deformation conditions and considering the effect of the strain rate, deformation temperature and strain on flow stress synthetically. Error analysis shows that the constructed constitutive relationship has good accuracy, in the range of 900 ~ 1150 °C the error is less than 10% of the data points are accounted for 97.4% of all data points, can conform the requirements of plastic processing.

Investigation of the Hot Deformation Behavior of an Al-Mg-Sc-Zr Alloy under Plane Strain Condition

2014 ◽  
Vol 611-612 ◽  
pp. 76-83 ◽  
Author(s):  
Johannes Taendl ◽  
Martina Dikovits ◽  
Cecilia Poletti
Keyword(s):  
Strain Rate ◽  
Plane Strain ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Hot Deformation Behavior ◽  
Flow Curves ◽  
Increasing Temperature ◽  
Zr Alloy

This study investigates the hot deformation behavior of a new Al-Mg-Sc-Zr alloy under plane strain conditions. Flow curves corrected for deformation heating were calculated for strain rates between 0.01 and 10s-1 in a temperature range of 200 to 400°C. To evaluate the deformation behavior, strain rate sensitivity as well as flow localization parameter maps were calculated for strains of 0.2, 0.4, and 0.6. In addition, microstructural investigations and hardness measurements were performed for selected samples. It was shown that the flow stress decreased with deacreasing strain rate and increasing temperature. The best formability was observed for high strain rates and low temperatures as well as for low strain rates and high temperatures. In these cases no flow instabilities were observed.

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