scholarly journals Study on critical damage factor and the constitutive model including dynamic recrystallization softening of AZ80 magnesium alloy

2013 ◽  
Vol 45 (2) ◽  
pp. 199-208 ◽  
Author(s):  
Y. Xue ◽  
Z.M. Zhang ◽  
Y.J. Wu
Keyword(s):  
Magnesium Alloy ◽  
Constitutive Model ◽  
Dynamic Recrystallization ◽  
Strain Rates ◽  
Damage Factor ◽  
Strain And Strain Rate ◽  
Az80 Magnesium Alloy ◽  
Az80 Alloy ◽  
Process Simulator ◽  
Critical Damage

Quantities AZ80 magnesium alloy billets were compressed with 60 % height reduction on hot process simulator at 473, 523, 573, 623, 673, 723 K under strain rates of 0.001, 0.01, 0.1, 1 and 10 s-1. In order to predict the occurrence of surface fracture, the critical damage factor based on the Cockcroft-Latham equation were obtained by analysing the results of the corresponding finite element calculation. The results show that the critical damage factor at 523, 573, 623, 673 K under strain rates of 0.001, 0.01, 0.1 and 1 s-1 is not a constant but varies in a range from 0.1397 to 0.4653. Meanwhile, a constitutive model with a few parameters is used to characterize the dynamic recrystallization strain softening of AZ80 alloy, which comprehensively reflect the effects of the deformation temperature, strain and strain rate on the flow stress.

A Study on the Phenomenological Constitutive Model of Mg-12Gd-5Y-3Zn-0.6Zr Magnesium Alloy Forming at Elevated Temperature

2014 ◽  
Vol 624 ◽  
pp. 71-76
Author(s):  
Guang Lu ◽  
Zhi Min Zhang ◽  
Yong Xue ◽  
Bao Cheng Li
Keyword(s):  
Elevated Temperature ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Constitutive Model ◽  
Strain Softening ◽  
True Strain ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Process Simulator ◽  
Temperature Strain

Quantities Mg-12Gd-5Y-3Zn-0.6Zr magnesium alloy billets were compressed with true strain 0.7 on hot process simulator at 350,400,450,480°C under strain rates of 0.001, 0.01, 0.1 and 0.5s-1. A constitutive model with a few parameters is used to characterize the dynamic recrystallization strain softening of Mg-12Gd-5Y-3Zn-0.6Zr alloy, which comprehensively reflect the effects of the deformation temperature, strain and strain rate on flow stress.

Study on the Critical Damage Value and Processing Map of AZ80 Magnesium Alloy Forming at Elevated Temperatures

2013 ◽  
Vol 275-277 ◽  
pp. 1904-1910
Author(s):  
Yong Xue ◽  
Zhi Min Zhang ◽  
Yao Jin Wu
Keyword(s):  
Magnesium Alloy ◽  
Elevated Temperatures ◽  
Processing Parameters ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests ◽  
Az80 Magnesium Alloy ◽  
Dynamic Material Modeling ◽  
Az80 Alloy ◽  
Critical Damage

In the present research, a series of AZ80 magnesium alloy billets were compressed with 60% height reduction on hot process simulator at temperatures of 473,523,573,623,673,723K under strain rates of 0.001, 0.01, 0.1,1 and 10s-1. The value of the Cockcroft-Latham equation, i.e. critical damage value, was calculated from the finite element calculations for the compression tests. The results show that the critical damage value is not a constant but varies in a range from 0.1397 to 0.4653. Meanwhile, the processing maps based on the Dynamic Material Modeling (DMM) were constructed. From the processing maps, the optimal deformation processing parameters are the deformation temperatures ranging from 573 to 623K and strain rates ranging from 0.001 to 0.01s-1 in view of improving the mechanical properties of AZ80 alloy component.

A Study on Processing Map and Flow Stress Model of AZ80 Magnesium Alloy Forming at Elevated Temperature

2011 ◽  
Vol 121-126 ◽  
pp. 3-9
Author(s):  
Yong Xue ◽  
Zhi Min Zhang ◽  
Yao Jin Wu
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Processing Parameters ◽  
Strain Rates ◽  
Processing Maps ◽  
Stress Model ◽  
Az80 Magnesium Alloy ◽  
Dynamic Material Modeling ◽  
Az80 Alloy ◽  
Flow Stress Model

Quantities AZ80 magnesium alloy billets were compressed with 60% height reduction on hot process simulator at 200,250,300,350,400,450°C under strain rates of 0.001, 0.01, 0.1,1 and 10s-1.The processing maps based on the Dynamic Material Modeling (DMM) were constructed, which is useful to analyze the deformation mechanism and the destabilization mechanism of AZ80 alloy. If the mechanical property of AZ80 alloy is taken into consideration, the optimal deformation processing parameters from the processing maps are the deformation temperatures ranging from 300 to 350°C and strain rates ranging from 0.001 to 0.01s-1. Meanwhile, a flow stress model with eight parameters is used to characterize the dynamic recrystallization strain softening of AZ80 alloy.

Thermal Deformation Property and Constitutive Model of AZ80 Magnesium Alloy

2013 ◽  
Vol 712-715 ◽  
pp. 674-677
Author(s):  
Fang Wang ◽  
Zhong Tang Wang
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Constitutive Model ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Thermal Deformation ◽  
Deformation Property ◽  
Az80 Magnesium Alloy ◽  
Calculation Results ◽  
Relative Errors

Thermal Deformation Property and Constitutive Model of AZ80 Magnesium Alloy had been studied with thermal simulation experiment. Dynamic recrystallization for AZ80 magnesium alloy had occurred under different strain rate at 583K(310°C). Dynamic recrystallization had occurred more completely and the grain size was reducing with increasing of strain rate. Dynamic recrystallization had occurred more completely and the grain size was reducing with increasing of strain rate. According the Arrhenius equation, a kind of constitutive equation of AZ80 Magnesium alloy which considered the strain had been put forward, and the relative errors between calculation results by the stress-strain model and experiment results are less than 10.5%.

scholarly journals Influence of Deformation Conditions on the Critical Damage Factor of AZ31 Magnesium Alloy

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Li-juan Pang ◽  
Xin Shang ◽  
Xuefeng Zhang
Keyword(s):  
Magnesium Alloy ◽  
Constitutive Model ◽  
Strain Rate ◽  
Outer Edge ◽  
Az31 Magnesium Alloy ◽  
Damage Factor ◽  
Finite Element Program ◽  
Softening Behavior ◽  
Element Program ◽  
Critical Damage

The influence of deformation conditions on the critical damage factor of AZ31 magnesium alloy was analyzed in this paper. Physical experiments and numerical simulation were used to study the critical damage factor. Compression test was carried out using a Gleeble 1500 device at temperatures between 250°C and 400°C, as well as strain rates from 0.01 s−1 to 1 s−1. True stress-strain curves of samples were obtained. Based on experimental data, an Arrhenius constitutive model was constructed. Material performance parameters and constitutive model were inputted into the finite element program DEFORM. Simulation results show that the maximum damage appears on the outer edge of the upsetting drum, and damage softening behavior is more sensitive to strain rate. According to the concept of damage sensitive rate, its values were computed. The intersection of line fitted and horizontal axis was obtained in the fracture step, and its relative maximum damage value was as the critical damage factor. The distribution of the critical damage value shows that it is not a constant but fluctuates within the range of 0.1445–0.3759, and it is more sensitive to strain rate compared with temperature.

A Study on the Phenomenological Constitutive Models of AZ80 and AZ31 Magnesium Alloy Forming at Elevated Temperatures

2011 ◽  
Vol 328-330 ◽  
pp. 2394-2399 ◽  
Author(s):  
Yong Xue ◽  
Zhi Min Zhang ◽  
Yao Jin Wu ◽  
Guang Lu
Keyword(s):  
Magnesium Alloy ◽  
Strain Softening ◽  
Elevated Temperatures ◽  
Constitutive Models ◽  
Az31 Alloy ◽  
Az31 Magnesium Alloy ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Process Simulator ◽  
Temperature Strain

Quantities AZ80 and AZ31 magnesium alloy billets were compressed with 60% height reduction on hot process simulator at 150,200,250,300,350,400,450°C under strain rates of 0.001, 0.01, 0.1,1 and 10s-1.A constitutive model with a few parameters is used to characterize the dynamic recrystallization strain softening of AZ80 and AZ31 alloy, which comprehensively reflect the effects of the deformation temperature, strain and strain rate on flow stress.

Critical damage value of AZ31B magnesium alloy with different temperatures and strain rates

Rare Metals ◽  
2015 ◽  
Author(s):  
Jing-Ren Dong ◽  
Ding-Fei Zhang ◽  
Yu-Feng Dong ◽  
Fu-Sheng Pan ◽  
Sen-Sen Chai
Keyword(s):  
Magnesium Alloy ◽  
Strain Rates ◽  
Az31b Magnesium Alloy ◽  
Different Temperatures ◽  
Critical Damage

scholarly journals Effect of Cyclic Expansion-Extrusion Process on Microstructure, Deformation and Dynamic Recrystallization Mechanisms, and Texture Evolution of AZ80 Magnesium Alloy

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yong Xue ◽  
Shuaishuai Chen ◽  
Haijun Liu ◽  
Zhimin Zhang ◽  
Luying Ren ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
Texture Evolution ◽  
Extrusion Process ◽  
Basal Texture ◽  
Continuous Dynamic Recrystallization ◽  
Distributed Structure ◽  
Texture Intensity ◽  
Az80 Magnesium Alloy

The microstructure, deformation mechanisms, dynamic recrystallization (DRX) behavior, and texture evolution of AZ80 magnesium alloy were investigated by three-pass cyclic expansion-extrusion (CEE) tests. Optical microscopy (OM), electron back-scattered diffraction (EBSD), and X-ray diffraction (XRD) were employed to study microstructure, grain orientation, DRX mechanism, and texture evolution. The results show that the grain sizes decrease continuously with the increase of CEE pass. The grain refinement effect of the first pass is the most remarkable, and there appear a large number of twins. After three-pass CEE, a well-distributed structure with fine equiaxed grains is obtained. With the increase of CEE pass, the deformation mechanism changes from twinning to slipping and the DRX mechanism changes mainly from twinning-induced dynamic recrystallization (TDRX) to rotation dynamic recrystallization (RDRX) and then to continuous dynamic recrystallization (CDRX). The grain misorientation between the new grains and matrix grains deceases gradually, and a relatively small angle misorientation is obtained after three-pass CEE. Grain misorientations of the first two passes are attributed to TDRX and RDRX behaviors, respectively. The grain refinement changes the deformation and DRX mechanisms of CEE process, which leads the (0002) basal texture intensity first decrease and then increase suddenly. Eventually, the extremely strong basal texture is formed after three-pass CEE.

Superplasticity in Friction Stir Processed AZ80 Magnesium Alloy

2010 ◽  
Vol 433 ◽  
pp. 241-246 ◽  
Author(s):  
Yoshimasa Takayama ◽  
Itsuki Takeda ◽  
Toshiya Shibayanagi ◽  
Hajime Kato ◽  
Kunio Funami
Keyword(s):  
Magnesium Alloy ◽  
Cross Section ◽  
Room Temperature ◽  
Maximum Stress ◽  
Strain Rates ◽  
Friction Stir ◽  
Az80 Magnesium Alloy ◽  
Lower Strain ◽  
Elongation To Failure ◽  
Scanning Electron

Superplasticity in an AZ80 magnesium alloy subjected to friction stir processing (FSP) has been investigated. FSP was carried out at two traveling speeds of 150mm/min and 300mm/min for grain refinement. Optical microscopy on cross section to processing direction revealed obvious differences in size and feature between the stir zones at the two traveling speeds. The hardness of FSPed sample at the room temperature was about 30HV higher than that of as-received one. The maximum stress of the FSPed sample was reduced remarkably at lower strain rates compared with those of the as-received one at 573K and 673K. On the other hand, the elongation to failure of the FSPed sample showed ten to thirteen times larger than that of the as-received one at 573K and low strain rates. Further surface morphology near the fracture tip was observed by scanning electron microscopy to discuss deformation mechanism at high temperatures.

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