Hot Deformation Behavior and Constitutive Equation of 5E61 Aluminum Alloy

2017 ◽  
Vol 898 ◽  
pp. 9-16
Author(s):  
Ya Liu ◽  
Hui Huang ◽  
R. Liu ◽  
Sheng Ping Wen ◽  
Xiao Lan Wu ◽  
...  

The hot deformation behavior of aluminum alloy 5E61 was studied by hot compressive tests using a Gleeble-1500 thermal simulator. The tests were performed at temperatures varying from 250°C to 500°C and strain rates ranging from 0.001 s-1 to 10s-1. The results achieved in the present study showed that the steady flow stress increases with decreasing temperature and increasing strain rate, in accordance with the Zener-Hollomon parameter. The related microstructure is sensitive to deformation temperature, strain rate and strain. The constitutive equation based on true stress-true strain curves has been developed by hyperbolic sine equation with the hot deformation activation energy of 153.907KJ/mol. The softening mechanism could be ascribed dominantly to dynamic recovery. The results of TEM observation suggested that Mn-containing particles and Al3(Er,Zr) phase have precipitated in the aluminum matrix and pin the dislocations, which could effectively inhibit the dynamic recrystallization.

2013 ◽  
Vol 17 (5) ◽  
pp. 1523-1528
Author(s):  
Bao-Hua Jia ◽  
Wei-Dong Song ◽  
Hui-Ping Tang ◽  
Jian-Guo Ning

Isothermal compression tests of TC18 titanium alloy at the deformation temperatures ranging from 25?C to 800?C and strain rate ranging from 10-4 to 10-2 s-1 were conducted by using a WDW-300 electronic universal testing machine. The hot deformation behavior of TC18 was characterized based on an analysis of the true stress-true strain curves of TC18 titanium alloy. The curves show that the flow stress increases with increasing the strain rate and decreases with increasing the temperature, and the strain rate play an important role in the flow stress when increasing the temperatures. By taking the effect of strain into account, an improved constitutive relationship was proposed based on the Arrhenius equation. By comparison with the experimental results, the model prediction agreed well with the experimental data, which demonstrated the established constitutive relationship was reliable and can be used to predict the hot deformation behavior of TC18 titanium alloy.


2016 ◽  
Vol 684 ◽  
pp. 35-41 ◽  
Author(s):  
S.V. Rushchits ◽  
E.V. Aryshensky ◽  
S.M. Sosedkov ◽  
A.M. Akhmed'yanov

The deformation behavior of 1565ch alloy under the plane-strain conditions in the temperature range of 350–490 оС and strain rates range of 0,1–10 s-1 is studied. The expression for steady flow stress as the functions of temperature of deformation and strain rate is obtained. It is established that 1565ch alloy with zirconium addition shows higher strain resistance and less tendency to dynamic and static recrystallization than AMg6.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 846 ◽  
Author(s):  
Changmin Li ◽  
Yuan Liu ◽  
Yuanbiao Tan ◽  
Fei Zhao

The H13-mod steel optimized by composition and heat treatment has reached the performance index of the shield machine hob. The hot deformation behavior of the H13-mod steel was investigated by compression tests in the temperature range from 900 to 1150 °C and the strain rate range from 0.01 to 10 s−1. The true stress-strain curve showed that the rising stress at the beginning of deformation was mainly caused by work hardening. After the peak stress was attained, the curve drop and the flow softening phenomenon became more obvious at low strain rates. The flow behavior of the H13-mod steel was predicted by a strain-compensated Arrhenius-type constitutive equation. The relationship between the material constant in the Arrhenius-type constitutive equation and the true strain was established by a sixth-order polynomial. The correlation coefficient between the experimental value and the predicted value reached 0.987, which indicated that the constitutive equation can accurately estimate the flow stress during the deformation process. A good linear correlation was achieved between the peak stress (strain), critical stress (strain) and the Zener‒Hollomon parameters. The processing maps of the H13-mod steel under different strains were established. The instability region was mainly concentrated in the high-strain-rate region; however, the microstructure did not show any evidence of instability at high temperatures and high strain rates. Combined with the microstructure and electron backscattered diffraction (EBSD) test results under different deformations, the optimum hot working parameters were concluded to be 998–1026 °C and 0.01–0.02 s−1 and 1140–1150 °C and 0.01–0.057 s−1.


2013 ◽  
Vol 721 ◽  
pp. 82-85
Author(s):  
Jian Bin Zhang ◽  
Dong Mei Yu ◽  
Shao Rui Niu ◽  
Gen Shun Ji

The hot deformation behavior and microstructure evolution of 430 ferritic stainless steel (430 FSS) were investigated within the temperature range of 950°C~1150°C at the strain rate of 0.01 s-1, 0.1 s-1, and 1.0 s-1using a thermo-mechanical simulator. The effects of temperature and strain rate on the flow behavior and microstructures of 430 ferritic stainless steel at reduction ratio 50 % were analyzed. Results indicated that the apparent stress exponent and the apparent activation energy of the steel were about 1.08 and 344 kJ/mol, respectively. The hot deformation equation of 430 was considered as. There was a relationship between the softening mechanism and Zener-Hollomon parameter (abbreviated Z). With the Z value increasing from 4.30×1010to 5.00×1014, the hot deformation peak stress correspondingly increased from 10.74 MPa to 76.02MPa.


Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 429
Author(s):  
Yuehua Kang ◽  
Zhenghua Huang ◽  
Hu Zhao ◽  
Chunlei Gan ◽  
Nan Zhou ◽  
...  

Under compressive testing at 400 °C and a strain rate range of 0.05–5 s−1, the hot deformation behavior and microstructure evolution of an as-cast (AC), as-extruded (with a bimodal grain structure (named as Ex-1) or a relatively uniform fine grain structure (Ex-2)) WE43 alloy have been investigated and compared. The results indicate that the AC sample exhibits the highest peak stress, while the Ex-2 sample has the lowest value. Within the AC material, fine grains were firstly formed along the pancake-like deformed grains (as a necklace structure). The necklace structure was also formed within the Ex-1 and Ex-2 materials at high strain rates of 0.5 and 5 s−1. However, a lamellar structure that the coarse elongated grains divided by parallel boundaries was formed within the Ex-1 material. A relatively more homogeneous fine grain structure is achieved after a true strain of 1.0 within the Ex-2 material at a low strain rate of 0.05 s−1. In addition, a discontinuous dynamic recrystallization mechanism by grain boundary bulging is found to occur. After a true strain of 1.2, a (0001) fiber texture, a typical rare earth (RE) texture, and a relatively random texture are formed within the AC, Ex-1, and Ex-2 WE43 alloy material, respectively.


Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 451
Author(s):  
Yexin Jiang ◽  
Xu Wang ◽  
Zhou Li ◽  
Zhu Xiao ◽  
Xiaofei Sheng ◽  
...  

The hot deformation behavior of Cu-20.0Ni-5.0Sn-0.25Zn-0.22Mn was investigated using a Gleeble-3500 thermal simulator with a temperature range from 720 °C to 880 °C and a strain rate range from 0.001 s−1 to 1 s−1. The results show that the flow stress increased with the increase of the strain rate and the decrease of the temperature. The constitutive equation of the alloy was established based on the peak flow stress. Figures of the power dissipation efficiency and flow instability with the variable of the true strain from 0.2 to 0.8 displayed the dynamic change of power dissipation efficiency and the instability area. The domain of 730–770 °C and 0.001–0.01 s−1 possessed a power dissipation efficiency over 40% throughout the whole deformation. The flow instability always appeared at a high strain rate from 0.1 s−1 to 1 s−1 during the whole deformation process. The nucleation site of the dynamic recrystallization generally appeared along the grain boundaries, indicating the discontinuous dynamic recrystallization mechanism. The appropriate conditions for deformation with a true strain of 0.9 is in a safe domain (820–860 °C with a strain rate of 0.001–0.01 s−1). There were four kinds of variation tendencies of the power dissipation efficiency with the increase of the true strain under various conditions, suggesting a changing situation for the main softening mechanisms.


2017 ◽  
Vol 898 ◽  
pp. 291-299
Author(s):  
Di Feng ◽  
Xin Ming Zhang ◽  
Sheng Dan Liu

The hot deformation behaviors of 7A55 aluminum alloy were investigated by compression tests at temperatures ranging from 270°C to 450°C and strain rate ranging from 0.1s−1 to 25s−1. Tha rResults show that the flow stress increased with increasing strain rate and decreasing temperature. A two-stage constitutive equation was established and the hot deformation activation energy was 140 kJ/mol. EBSD observations show that the fine and equiaxed grains with the misorientation angle above 15° nucleated at the initial grain boundaries under high temperature and low strain rate conditions. It is concluded that the softening mechanism of 7A55 aluminum alloy is dynamic recovery (DRV), together with a partial dynamic recrystallization (DRX). The nucleation mechanism of DRX could be explained by the strain induced grain boundary migration (SIBM). The DRX softening model was established based on the dislocation density theory finally.


Author(s):  
C. Menapace ◽  
N. Sartori ◽  
M. Pellizzari ◽  
G. Straffelini

The hot deformation behavior of four different steels in the as-cast condition was investigated by means of hot compression tests conducted at temperatures ranging from 1100 °C up to 1200 °C, and at strain rates in between 0.12 and 2.4 s−1. The primary focus of this work was to check the possibility to increase the strain rate during the rough preliminary working of the ingots, i.e., to adopt a rough rolling process in place of the more conventional rough forging. The second aim of the research was to study the influence of the different characteristics of these steels in their as-cast conditions on their hot deformation behavior. It was seen that in all deformation conditions, the stress–strain compression curves show a single peak, indicating the occurrence of dynamic recrystallization (DRX). The hot deformation behavior was studied in both the condition of dynamic recovery (DRV), modeling the stress–strain curves in the initial stage of deformation, and DRX. Data of modeling were satisfactorily employed to estimate the flow stress under different conditions of temperature and strain rate. The experimental values of the activation energy for hot deformation, QHW, were determined and correlated to the chemical composition of the steels; a power law curve was found to describe the relation of QHW and the total amount of substitutional elements of the steels. The critical strain for DRX, εc, was determined as a function of the Zener–Hollomon parameter and correlated to the peak strain, εp. A ratio εc/εp in the range 0.45–0.65 was found, which is in agreement with literature data. All this information is crucial for a correct design of the rough deformation process of the produced ingots.


2011 ◽  
Vol 117-119 ◽  
pp. 921-924
Author(s):  
Jiang Feng ◽  
Bao Hong Tian ◽  
Yong Liu

The hot deformation behavior of the Al2O3/Cu-10vol%WC composite is investigated by isothermal compression test on a Gleeble 1500D thermal-mechanics simulator at the temperature ranges from 350°C to 750°C and the strain rate ranges from 0.01s-1 to 5s-1. The results show that high-temperature flow stress-strain curves of Al2O3/Cu-WC composites have typical features of the softening mechanism of dynamic recovery and dynamic recrystallization. The peak stress increases with the decreasing of deformation temperature or the increasing of strain rate. The hyperbolic-sine type equation shows good agreement with the experimental stress. Upon the basis of the above experimental results, the activation energy of the composite is calculated as 208.34kJ/mol.


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