Rate controlling mechanisms during hot deformation of Mg–3Gd–1Zn magnesium alloy: Dislocation glide and climb, dynamic recrystallization, and mechanical twinning

2015 ◽  
Vol 68 ◽  
pp. 228-231 ◽  
Author(s):  
H. Mirzadeh ◽  
M. Roostaei ◽  
M.H. Parsa ◽  
R. Mahmudi
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Mechanical Twinning ◽  
Dislocation Glide

Compressive Deformation of ZK60 Magnesium Alloy at Elevated Temperature

2007 ◽  
Vol 353-358 ◽  
pp. 631-634 ◽  
Author(s):  
Chun Yan Wang ◽  
Kun Wu ◽  
Ming Yi Zheng
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Flow Behavior ◽  
Testing Machine ◽  
Mechanical Twinning ◽  
Dislocation Slip ◽  
Strain Rates ◽  
Lower Temperature ◽  
Zk60 Magnesium Alloy

The high temperature compressive tests of squeeze casting ZK60 magnesium alloy with temperatures of 573-723K and strain rate in the range of 0.001-1s-1 were performed on Gleeble-1500D thermal simulator testing machine. Optical microscopy was performed to elaborate on the dynamic recrystallization (DRX) grain growth. TEM findings indicate that mechanical twinning, dislocation slip, and dynamic recrystallization are the materials typical deformation features. Variations of flow behavior with deformation temperature as well as strain rate were analyzed. Analysis of the flow behavior and microstructure observations indicated that flow localization was observed at lower temperature and higher strain rates, which should be avoided during mechanical processing. Dynamic recrystallization occurred at higher temperature and moderate strain rates, which improved the ductility of the material. The optimum hot working conditions for ZK60 alloy were suggested.

Modeling of strain hardening and dynamic recrystallization of ZK60 magnesium alloy during hot deformation

2012 ◽  
Vol 22 (2) ◽  
pp. 246-254 ◽  
Author(s):  
Yun-bin HE ◽  
Qing-lin PAN ◽  
Qin CHEN ◽  
Zhi-ye ZHANG ◽  
Xiao-yan LIU ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Hardening ◽  
Hot Deformation ◽  
Zk60 Magnesium Alloy

Effect of Initial Grain Size on Deformation Behavior and Dynamic Recrystallization of Magnesium Alloy AZ31

2005 ◽  
Vol 488-489 ◽  
pp. 223-226 ◽  
Author(s):  
Xu Yue Yang ◽  
Masayoshi Sanada ◽  
Hiromi Miura ◽  
Taku Sakai
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
Hot Deformation ◽  
Structural Changes ◽  
Kink Bands ◽  
Alloy Az31 ◽  
Continuous Dynamic Recrystallization ◽  
Magnesium Alloy Az31 ◽  
Continuous Dynamic

Hot deformation and associated structural changes were studied in compression of a magnesium alloy AZ31 with initial grain sizes (D0) of 22 µm and 90 µm at a temperature of 573K. D0 influences significantly the flow curve and the kinetics of grain refinement during hot deformation. For D0 = 22 µm, grain fragmentation takes place due to frequent formation of kink bands initially at corrugated grain boundaries and then in grain interiors in low strain, followed by full development of new fine grains in high strain. For D0 = 90 µm, in contrast, twinning takes place in coarser original grains, and then kink bands and new fine grains are formed mainly in finer ones at low strains. Then new grains are formed in necklace along the boundaries of coarse original grains, followed by their development into the grain interiors. Grain refinement in the Mg alloy can be concluded to result from a series of deformation-induced continuous reactions, they are essentially similar to continuous dynamic recrystallization (cDRX).

scholarly journals Characterization of Hot Deformation Behavior and Processing Maps of Mg-3Sn-2Al-1Zn-5Li Magnesium Alloy

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1262 ◽  
Author(s):  
Yuhang Guo ◽  
Yaodong Xuanyuan ◽  
Chunnan Lia ◽  
Sen Yang
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Maps ◽  
Compression Tests ◽  
Softening Mechanism ◽  
Signal Peak ◽  
The Operating Mechanism ◽  
The Stability

The dynamic microstructure evolution of Mg-3Sn-2Al-1Zn-5Li magnesium alloy during hot deformation is studied by hot compression tests over the temperature range of 200–350 °C under the strain rate of 0.001–1 s−1, whereafter constitutive equations and processing maps are developed and constructed. In most of cases, the material shows typical dynamic recrystallization (DRX) features, with a signal peak value followed by a gradual decrease. The value of Q (deformation activation energy) is 138.89414 kJ/mol, and the instability domains occur at high strain rate but the stability domains are opposite, and the optimum hot working parameter for the studied alloy is determined to be 350 °C/0.001 s−1 according to the processing maps. Within 200–350 °C, the operating mechanism of dynamic recrystallization (DRX) of Mg-3Sn-2Al-1Zn-5Li alloy during hot deformation is mainly affected by strain rate. Dynamic recrystallization (DRX) structures are observed from the samples at 300 °C/0.001 s−1 and 350 °C/0.001 s−1, which consist of continuous DRX (CDRX) and discontinuous DRX (DDRX). However, dynamic recovery (DRV) still dominates the softening mechanism. At the grain boundaries, mass dislocation pile-ups and dislocation tangle provide sites for potential nucleation. Meanwhile, flow localization bands are observed from the samples at 200 °C/1 s−1 and 250 °C/0.1 s−1 as the main instability mechanism.

Study on Flow Stress Characteristics of AZ31B under Multi-Stage Hot Deformation

2013 ◽  
Vol 310 ◽  
pp. 117-123
Author(s):  
Xin Tong Wu ◽  
Zhao Yang Jin ◽  
Juan Liu ◽  
Xin Huang
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Temperature Jump ◽  
Peak Strain ◽  
Stored Energy ◽  
Deformation Degree ◽  
Multi Stage

In order to improve the understanding of the rheological behavior of magnesium alloy AZ31B under multi-stage hot deformation, a series of isothermal compressing experiments with height reduction of 60% were performed at the temperatures of 250°C, 300°C, 350°C and 400°C and the strain rates of 0.01 s−1and 0.1 s−1 on a Gleeble 1500 thermo-mechanical simulator. The effects of temperature (jump), strain rate (jump), deformation degree and deformation interval time on the flow stress characteristics are investigated and discussed. It is shown that in the dual-stage deformation process with temperature jump or strain rate jump, values of peak stress and peak strain at the second-stage are lower than those at single-stage. The reason for this change is due to the deformation stored energy still retained in the material after its release during the first-stage deformation and deformation interval, such as dynamic recrystallization, meta-dynamic recrystallization, static recovery and static recrystallization The deformation resistance of the multi-stage deformation of AZ31B can be reduced by increasing the deformation degree at the first-stage or the deformation interval because it leads to adequate release of deformation stored energy, which improves the plastic formability of magnesium alloy.

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