The Flow Stress and Microstructure Evolution during Hot Compression of Casting AZ91D Magnesium Alloy

2011 ◽  
Vol 403-408 ◽  
pp. 670-674
Author(s):  
Hong Bo Li ◽  
Me Lu ◽  
Cai Jie Li
Keyword(s):  
Mathematical Model ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Microstructure Evolution ◽  
Az91d Magnesium Alloy ◽  
Gleeble 3500 ◽  
Gleeble 3500 System ◽  
The Mathematical Model

The flow stress at the temperature of 250~450°Cand different strain rate of casting AZ91D magnesium alloy was studied through experiment, which adopting the Gleeble 3500 system of DSI company. The mathematical model of flow stress containing the softening factor which is suitable for casting AZ91D magnesium alloy was proposed. The temperature and strain rate conditions during full dynamic recrystallization were found by observing the microstructure.

Establishment of Flow Stress Model of EW75 Alloy

2013 ◽  
Vol 423-426 ◽  
pp. 241-246
Author(s):  
Ming Long Ma ◽  
Kui Zhang
Keyword(s):  
Mathematical Model ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Strain Rate ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Stress Strain ◽  
Deformation Degree ◽  
Maximum Deformation ◽  
The Mathematical Model

The behavior evolvement of Mg-7.22Gd-4.84Y-1.26Nd-0.58Zr (EW75) magnesium alloy during the hot deformation process was discussed. The flow stress behavior of magnesium alloy over the strain rate range 0.002s-1to 2s-1and the temperature range 623K to 773K had been researched on Gleeble-1500D hot simulator under the maximum deformation degree 60%. A mathematical model was established to predict the stress-strain curves of this alloy during deformation. The experimental results showed that the stress-strain curves were obviously affected by the strain rates and deformation temperatures. The mathematical model could predict the stress-strain curves when the strain rates were under 0.2-1, but there was significant error in some of stress-strain curves when the strain-rate was 2-1by the reason of deformation temperature rising.

Hot Compression Deformation Behavior of Mg-Gd-Y-Zn-Zr Alloy

2014 ◽  
Vol 680 ◽  
pp. 15-22 ◽  
Author(s):  
Guang Lu ◽  
Zhi Ping Xie ◽  
Zhi Min Zhang ◽  
Yong Biao Yang ◽  
Bao Cheng Li
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Great Influence ◽  
Peak Stress ◽  
Maximum Error ◽  
Continuous Dynamic Recrystallization ◽  
Stress Behaviors ◽  
Continuous Dynamic

The deformation behaviors of as-cast Mg-11Gd-2Y-Zn-Zr magnesium alloy were investigated by compression test with Gleeble-1500 thermal simulator at temperature of 623-753K and strain rate of 0.01-0.5 s-1. The flow stress behaviors of the magnesium alloy were carried out at a strain of 0.7. The strain rate and deformation temperature had great influence on the flow stress behaviors. The flow stress increases with increasing strain rate and decreasing temperature. The flow stress has more than one peak stress at a strain rate of 0.5s-1showing continuous dynamic recrystallization (DRX) mechanism, while other flow stresses exhibited only one peak stress indicating discontinuous dynamic recrystallization (DDRX) mechanism. It was also found that the flow stress behavior could be described by the hyperbolic sine constitutive equation, in which the determined average activation energy is 273.426 kJ·mol-1. The maximum error value between calculated value and experimental value is 5.5%. The deformation map was also established, and the best parameter for hot working was found to be 0.1s-1/753k approximately.

Compressing Deformation and Microstructure of AZ61 Magnesium Alloy

2014 ◽  
Vol 1015 ◽  
pp. 203-206
Author(s):  
Quan Li ◽  
Jin Yang ◽  
Wen Jun Liu ◽  
Su Qin Luo ◽  
Ren Ju Cheng ◽  
...  
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Hot Compression ◽  
Compression Tests ◽  
Az61 Magnesium Alloy

Hot compression tests of AZ61 magnesium alloy were performed on gleeble1500D at strain rate ranged in 0.01~1s-1 and deformation temperature 350~400°C.The results show that the flow stress and microstructures strongly depend on the deformation temperature and the strain rate. When the temperature was reduced and the strain rate was enhanced, the area after dynamic recrystallization was enhanced, and the average dynamically recrystallied grain size reduce. But the dynamically recrystallied grain size was not well-proportioned. In this paper the 350°C×1s-1 was suggested.

scholarly journals Hot Deformation Behavior and Microstructure Evolution of a TiBw/Near α-Ti Composite with Fine Matrix Microstructure

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 481 ◽  
Author(s):  
Zhang ◽  
Lian ◽  
Chen ◽  
Sun ◽  
Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Microstructure Evolution ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Matrix Microstructure

The hot deformation behavior and microstructure evolution of a 7.5 vol% TiBw/near α-Ti composite with fine matrix microstructure were investigated under the deformation conditions in a temperature range of 800–950 °C and strain rate range of 0.001–1 s−1 using plane strain compression tests. The flow stress curves show different characteristics according to the various deformation conditions. At a higher strain rate (1 s−1), the flow stress of the composite continuously increases until a peak value is reached. The activation energy is 410.40 kJ/mol, much lower than the activation energy of as-sintered or as-forged composites. The decreased activation energy is ascribed to the breaking of the TiBw reinforcement during the multi-directional forging and the resultant fine matrix microstructure. Refined reinforcement and refined matrix microstructure significantly improve the hot deformation ability of the composite. The deformation conditions determine the morphology and fraction of α and β phases. At 800–900 °C and 0.01 s−1 the matrix α grains are much refined due to the continuous dynamic recrystallization (CDRX). The processing map is constructed based on the hot deformation behavior and microstructure evolution. The optimal hot processing window is determined to be 800–950 °C/0.001–0.01 s−1, which lead to CDRX of primary α grains or dynamic recovery (DRV) and dynamic recrystallization (DRX) of β phase.

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.

The Deformation Behavior of Thermal Compression for ZK30 Magnesium Alloy

2014 ◽  
Vol 541-542 ◽  
pp. 12-17
Author(s):  
Bao Dong Chen ◽  
Feng Guo ◽  
Jing Wen
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Type Equation ◽  
Nonlinear Flow ◽  
Thermal Compression ◽  
Deformation Behaviors

In order to improve the understanding deformation behaviors of thermal compressive of ZK30 magnesium alloy, carried out a series of thermal compressive tests with height reduction 60% of specimens were performed at deformation temperature range of 523-673 K, and strain rates range of 0.001-1 s−1 on Gleeble-1500 thermo-mechanical simulator. Based on an Arrhenius-type equation constructs a nonlinear flow model and its constitutive equation, are employed to study the deformation behavior and the relationship between deformation temperature, strain rate and flow stress. For higher deformation temperature and lower strain rate, the true stress-strain curves show a characteristic of dynamic recrystallization. With the increase of deformation temperature and the decrease of strain rate the flow stress decreases, also the dynamic recrystallization becomes easier.

Influnce of Grain Size on Dynamic Recrystallization of AZ31 Magnesium Alloy Rolling Sheet

2013 ◽  
Vol 395-396 ◽  
pp. 218-222 ◽  
Author(s):  
Chen Yang Xu ◽  
Fu Xiang Chu ◽  
Xiao Ling Xu ◽  
Hao Chen ◽  
Fang Gao
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Microstructure Evolution ◽  
Deformation Temperature ◽  
Az31 Magnesium Alloy ◽  
Deformation Condition ◽  
Evolution Characteristics ◽  
C 30

Microstructure evolution characteristics and the influence of the intial grain size on the dynamic recrystallization of AZ31 were investigated by rolling at deformation temperature of 280 °C, 30% reduction and strain rate of 5.6s-1. The results indicate that under the present deformation condition, when the grain size is 6.2μm the dynamic recrystallization does not occur , twinning dynamic recrystallization (TDRX) occurs when the original grain size are of 7.9μm and 12.7μm, when the original grain size is 21.1μm rotating dynamic recrystallization (RDRX) occurs.

Compression Deformation Behavior of AZ91D Magnesium Alloy at Elevated Temperature

2012 ◽  
Vol 184-185 ◽  
pp. 914-919 ◽  
Author(s):  
Yue Sheng Chai ◽  
Yong Zhe Chen ◽  
Wen Feng Liu ◽  
Gang Sun
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Hot Compression ◽  
Constant Flow ◽  
Compression Tests ◽  
Hot Compression Deformation ◽  
Az91d Magnesium Alloy ◽  
Compression Deformation

Hot compression tests of AZ91D magnesium alloy were performed on Gleeble1500 ranging from 0.001 to 1 s-1 and deformation temperature ranging from 200 to 400°C. The results show that flow stress is dependent on deformation temperature and strain rates．When strain rate is a constant, flow stress decreases with the increasing deformation temperature. Meanwhile, as deformation temperature is a constant, flow stress increases with the increase of strain rate, which can be demonstrated by a Zener-hollomon parameter in the hyperbolic-sine-type equation during hot compression deformation. The hot deformation activation energy is 176.01kJ/mol and the stress exponent is 7.85 during hot compression deformation of AZ91D magnesium alloy.

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