Microstructural Evolution of Magnesium Alloy during Hot Compression

2013 ◽  
Vol 446-447 ◽  
pp. 158-163
Author(s):  
Xing Cheng Li ◽  
Ya Lin Lu ◽  
Jiang Tao Wang ◽  
Lin Dou
Keyword(s):  
Elevated Temperature ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Process Parameters ◽  
Deformation Mechanism ◽  
Deformation Process ◽  
Hot Compression ◽  
Strain Rates ◽  
Dynamic Recrystallisation

Hot compression of AZ3l magnesium alloy was carried out at deformation temperatures of 523-723K and strain rates of 0.01-10s-1. The effects of deformation process on the microstructure and flow stress were investigated. The flow stress curves showed the characteristic of dynamic recrystallization (DRX) with deformation process parameters. Optical microscopy and TEM observations indicated that dynamic recrystallisation and twins structure were found during hot compression. Deformation mechanism of AZ3l magnesium alloy at elevated temperature was discussed in this paper.

Deformation Behavior of AZ31 Magnesium Alloy at Elevated Temperature

2013 ◽  
Vol 652-654 ◽  
pp. 1976-1979
Author(s):  
Ya Lin Lu ◽  
Xing Cheng Li ◽  
Hong Jin Wang ◽  
Xiao Ping Li
Keyword(s):  
Elevated Temperature ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Process Parameters ◽  
Deformation Behavior ◽  
Deformation Process ◽  
Strain Rates ◽  
Hot Compression Test ◽  
Dynamic Recrystallisation ◽  
Gleeble 3500

Hot compression test for AZ3l magnesium alloy at deformation temperatures of 523-723K and strain rates of 0.01-10s-1 were carried out using Gleeble-3500 thermo-mechanical simulator. The experimental results show that the flow stress and microstructure vary apparently with deformation process parameters. Microstructure observations show that dynamic recrystallisation (DRX) takes place during the deformation. The characteristic with the dynamic recrystallization change with the process parameters.

Dynamic Recrystallization and Microstructure Evolution in AZ31 Magnesium Alloy during Thermomechanical Processing

2005 ◽  
Vol 488-489 ◽  
pp. 215-218 ◽  
Author(s):  
Guang Jie Huang ◽  
Ling Yun Wang ◽  
Guang Sheng Huang ◽  
Fu Sheng Pan
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
High Temperatures ◽  
Critical Strain ◽  
Thermomechanical Processing ◽  
Stable State ◽  
Az31 Magnesium Alloy ◽  
Strain Rates ◽  
Peak Strain

The deformation behavior of AZ31 magnesium alloy has been investigated by isothermal compression at temperatures between 573-723K and at constant strain rates ranging from 10-3 -1s-1. It is shown that the form of flow stress curves is very sensitive to temperature and strain rate. In the experimental domain studied, the flow stresses are modeled using a power law with an average activation energy of 145.16 kJ/mol, and dynamic recrystallization (DRX) occurs. The critical strain for DRX is determined by analysis of flow stress curves. The ratio of the critical strain to the peak strain falls in the range of 0.4-0.5. At low temperatures and high strai rates, the deformation become macroscopically inhomogeneous, and the fracture of the specimens is accompanied by shear banding. Grain refinement resulting from DRX is less effective at high temperatures due to rapid grain growth. It is also shown that there is no difference between peak stress and stable state stress at high temperatures and lower strain rates, presenting the feature of continuous dynamic recrystallization (CDRX).

MICROSTRUCTURAL EVOLUTION AND FLOW BEHAVIOR OF TWIN-ROLL CAST AZ41 MAGNESIUM ALLOY DURING HOT COMPRESSION

2012 ◽  
Vol 26 (32) ◽  
pp. 1250181
Author(s):  
ZHIYI LIU ◽  
XU CHEN ◽  
YANHUI HOU ◽  
SUKBONG KANG
Keyword(s):  
Elevated Temperature ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Microstructural Evolution ◽  
Flow Behavior ◽  
Hot Compression ◽  
Dislocation Slip ◽  
Twin Roll Cast ◽  
Twin Roll

Microstructural evolution and flow behavior of twin-roll cast AZ41 magnesium alloy during hot compression were characterized by employing deformation temperature of 300°C, 350°C and 400°C, and strain rate ranging from 10-3 to 10-2 s -1. When compressed at different temperature (300°C, 350°C and 400°C) and strain rate (10-3 and 10-2 s -1) all stress strain curves showed a flow softening behavior before strained to 0.51 due to dynamic recrystallization, even though concurrent twinning was quite active. Twinning contributed to the flow hardening behavior appeared during the end of hot compression (ε > 0.51) at a strain rate of 10-2 s -1 and elevated temperature (300°C, 350°C and 400°C) in spite of the softening effect of concurrently occurred dynamic recrystallization. TEM image showed that discontinuous recrystallization occurred when deformed at elevated temperature as high as 400°C and the strain rate ranging from 10-2 to 10-3 s -1. It is suggested that dislocation slip, twinning and recrystallization develop in a cyclic mode from initial stage to the end of hot compression.

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.

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.

Hot Compression Deformation Simulation of AZ61B Magnesium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 373-377 ◽  
Author(s):  
Pan Xiao ◽  
Tian Mo Liu ◽  
Jian Peng ◽  
Fu Sheng Pan ◽  
Qing Liu
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Hot Compression ◽  
Strain Rates ◽  
Strain Rate Effects ◽  
Hot Compression Deformation ◽  
Compression Deformation ◽  
Rate Effects ◽  
Ebsd Technique ◽  
Stress And Deformation

The hot compression deformation behavior of AZ61B magnesium alloy has been investigated by using a Gleeble-1500D thermal simulator. The samples were compressed to a reduction of 50% at two temperatures (623 and 673K) with different strain rates (0.01, 0.1 and 1s-1). The relationships between flow stress and deformation temperature were analyzed, and the deformation activation energy and stress exponent were calculated based on the experimental results. With aid of the optical microscopy, scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) techniques, the microstructure and micro-texture of the deformed samples were characterized. The effects of the temperature and strain rates on the hot compression behavior of the AZ61B magnesium alloy have been investigated by detail analyses of the flow stress and microstructural characteristics of the deformed samples. For the 50% compressed samples, dynamic recrystallization occurred during the hot compression. The orientations of the dynamic recrystallized grains with equiaxed shape were investigated by EBSD technique. The relationships among the flow stress, dynamic recovery and recrystallization have been discussed by considering both the temperature and strain rate effects.

Flow Stress Correction of AZ80 Magnesium Alloy for Deformation Heating at High Strain Rates during Hot Compression

2010 ◽  
Vol 129-131 ◽  
pp. 1326-1330 ◽  
Author(s):  
Yan Lou ◽  
Luo Xing Li ◽  
Na Luan
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
High Strain ◽  
Fem Simulation ◽  
Hot Compression ◽  
Strain Rates ◽  
Compression Tests ◽  
High Strain Rates ◽  
Deformation Heating ◽  
Az80 Magnesium Alloy

Accurate description of the material flow stress behaviour is an essential requirement for FEM simulation of metal forming processes. In the present hot compression tests of AZ80 magnesium alloy were performed on Gleeble 3500 at strain rates between 0.01-50s-1 and deformation temperatures between 300-450°C to determine the flow stress data of the AZ80 magnesium alloy. It was noticed that with increasing strain rate, deformation heating become more pronounced since there is no time for heat escaping during hot compression tests. Thus, a flow stress correction for deformation heating at high strain rates was carried out for the calculation of the constants of constitutive equation. Validation tests were then performed. Good agreements between the predicted and measured values in extrusion pressure were achieved.

Flow Stress Constitutive Equation of AZ31 Magnesium Alloy for Hot Compression

2011 ◽  
Vol 328-330 ◽  
pp. 1614-1618 ◽  
Author(s):  
Wen Hua Wu ◽  
Yan Lou
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Constitutive Equation ◽  
Dynamic Recrystallization ◽  
Dynamic Recovery ◽  
Hot Compression ◽  
Az31 Magnesium Alloy ◽  
Multivariate Nonlinear Regression ◽  
Relative Errors ◽  
Kinetics Of

The AZ31 magnesium alloy flow stresses have been investigated in the strain rates of 0.03~3s-1and temperature range of 300~400°C. The result showed that dynamic recovery and dynamic recrystallization occurred obviously during the hot compression of AZ31 magnesium alloy. In order to represent the flow stress of plastic deformation accurately, the constitutive equation was built by using the dynamic recovery model and dynamic recrystallization model, and its parameters of the constitutive equation were determined by multivariate nonlinear regression analysis. The two-step constitutive equation not only expressed the variation of flow stress with strain rate, deformation temperature and strain, but also revealed the characteristic of dynamic recrystallization kinetics of AZ31 magnesium alloy. Its accuracy was higher than the flow stress of hyperbolic sine model, and the maximum relative errors of two constitutive equation models calculation values compared with experiment data were 5% and 6.5% respectively.

Hot Compressive Deformation of Rheocast AZ31 Magnesium Alloy

2006 ◽  
Vol 116-117 ◽  
pp. 742-745 ◽  
Author(s):  
Bi Cheng Yang ◽  
Shao Ming Zhang ◽  
Jun Xu ◽  
Li Kai Shi ◽  
Z. Fan
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Deformation Temperature ◽  
Cast Billet ◽  
Strain Rates ◽  
Cast Sample ◽  
Cast Specimen ◽  
Twin Screw ◽  
The Relationship

The billet of magnesium AZ31B was made by twin-screw rheo-cast, and the specimen cut from the rheo-cast billet and normal cast billet were compressed in Gleeble-3000 hot simulator. The deformation temperature was 300, 350, and the strain rates were 0.001~1s-1. The relationship among flow stress, deformation temperature and strain rates were analyzed. The variation of the microstructure was observed and compared after the specimen was hot compressed. The results show that the surface of the rheo-cast specimen is much more smooth than the normal cast specimen after the compression. The dynamic recrystallization had taken place during the compression and the recrystallized grain of rheo-cast sample is more tiny than normal cast specimen.

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