scholarly journals Recrystallization Microstructure Prediction of a Hot-Rolled AZ31 Magnesium Alloy Sheet by Using the Cellular Automata Method

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Ming Chen ◽  
Xiaodong Hu ◽  
Hongyang Zhao ◽  
Dongying Ju
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Cellular Automata ◽  
Process Analysis ◽  
Rolling Process ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Rolled Sheet ◽  
Element Analysis ◽  
Hot Rolled

A large reduction rolling process was used to obtain complete dynamic recrystallization (DRX) microstructures with fine recrystallization grains. Based on the hyperbolic sinusoidal equation that included an Arrhenius term, a constitutive model of flow stress was established for the unidirectional solidification sheet of AZ31 magnesium alloy. Furthermore, discretized by the cellular automata (CA) method, a real-time nucleation equation coupled flow stress was developed for the numerical simulation of the microstructural evolution during DRX. The stress and strain results of finite element analysis were inducted to CA simulation to bridge the macroscopic rolling process analysis with the microscopic DRX activities. Considering that the nucleation of recrystallization may occur at the grain and R-grain boundary, the DRX processes under different deformation conditions were simulated. The evolution of microstructure, percentages of DRX, and sizes of recrystallization grains were discussed in detail. Results of DRX simulation were compared with those from electron backscatter diffraction analysis, and the simulated microstructure was in good agreement with the actual pattern obtained using experiment analysis. The simulation technique provides a flexible way for predicting the morphological variations of DRX microstructure accompanied with plastic deformation on a hot-rolled sheet.

Research on Flow Stress of Magnesium Alloy Sheet under Warm and High Strain Rate Forming Condition

2011 ◽  
Vol 189-193 ◽  
pp. 2522-2525
Author(s):  
Zheng Hua Meng ◽  
Shang Yu Huang ◽  
Jian Hua Hu
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Process Simulation ◽  
High Strain ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Rate Condition ◽  
Magnesium Alloy Sheet

Process simulation is a powerful tool to predict material behaviors under specified deformation conditions, so as to optimize the processing parameters. The equation for flow stress is important to numerically analyze. However, the reported constitutive equations of magnesium alloy are only suitable for processing simulation with strain rate between 0.001-1s-1. In this paper, the strain-stress behavior of AZ31 under warm and high strain rate (>103s-1) condition has been investigated by split Hopkinson pressure bar experiments at elevated temperature. The results show that the influence of the temperature on flow stress is more obvious than that of strain rate; the flow stress decreases with the rise of temperature at a certain strain rate. Based on Johnson-Cook model, the constitutive equation of AZ31 magnesium alloy under warm and high strain rate condition has been given out by fitting the experimental data, which can be applied in process simulation of AZ31 magnesium alloy sheet forming.

scholarly journals Critical Rolling Process Parameters for Dynamic Recrystallization Behavior of AZ31 Magnesium Alloy Sheets

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2019
Author(s):  
Wenke Wang ◽  
Qing Miao ◽  
Xuemin Chen ◽  
Yang Yu ◽  
Wencong Zhang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Process Parameters ◽  
Rolling Direction ◽  
Rolling Process ◽  
Alloy Sheet ◽  
Rolling Temperature ◽  
Az31 Magnesium Alloy ◽  
Texture Intensity ◽  
C 30

In this work, the influence of various rolling temperatures and thickness reductions on the dynamic recrystallization (DRX) behavior of AZ31 magnesium alloy sheets was investigated. Meanwhile, the texture variation controlled by DRX behavior was analyzed. Results suggested that, with the help of DRX behavior, reasonable matching of rolling temperature and thickness reduction could effectively refine the grain size and improve the microstructure homogeneity. Using the grain refinement and microstructure homogeneity as the reference, the critical rolling process parameters were 400 °C—30%, 300 °C—30%, and 250 °C—40% in the present work. In terms of basal texture variation, the occurrence of twins produced the largest maximum texture intensity. However, for the sheets with DRX behavior, the maximum texture intensity decreased sharply, but would steadily increase with the growth of DRXed grain. Additionally, for DRXed grains, the <11-20>//RD (RD: rolling direction) grains would gradually annex the <10-10>//RD grains with the growth of DRXed grains, which finally made their texture component become the dominant texture state. However, when the deformation continued, the <10-10> in DRXed grains would rotate toward the RD again. Weighted by the fracture elongation of AZ31 magnesium alloy sheet, the critical thickness reductions were 30–40% under the rolling temperature of 400 °C.

Numerical-Experimental Characterization of a Superplastic AZ31 Magnesium Alloy

2007 ◽  
Vol 551-552 ◽  
pp. 317-322 ◽  
Author(s):  
G. Palumbo ◽  
Donato Sorgente ◽  
Luigi Tricarico ◽  
S.H. Zhang ◽  
W.T. Zheng ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Biaxial Tension ◽  
Thickness Distribution ◽  
Alloy Sheet ◽  
Experimental Results ◽  
Az31 Magnesium Alloy ◽  
Dome Height ◽  
Fe Model ◽  
Flow Parameters ◽  
Hot Rolled

In this work the superplastic behaviour of a hot rolled AZ31 magnesium alloy sheet under a biaxial tension test with the blow forming technique is presented and reported. The specimen dome height and its thickness distribution, during and after the test, have been used as characterizing parameters. A numerical FE model of the test has been developed in order to easily characterize the material and to directly analyze experimental results. The influence of the rolling cycle on the microstructure and consequently on the material behaviour has been also analyzed. A synergic use of experimental results and of the numerical model has been done for finding material constants in different situations. The material flow parameters have been found and results are presented.

Texture and Mechanical Properties of AZ31 Magnesium Alloy Sheets Processed by Symmetric/Asymmetric Combination Hot-Rolling

2010 ◽  
Vol 654-656 ◽  
pp. 719-722 ◽  
Author(s):  
J. Horiuchi ◽  
Hirofumi Inoue ◽  
Takayuki Takasugi
Keyword(s):  
Magnesium Alloy ◽  
Yield Strength ◽  
Hot Rolling ◽  
High Strength ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
High Yield ◽  
Rolled Sheet ◽  
Asymmetric Rolling ◽  
Double Peaks

Conventional symmetric rolling enhances yield strength by forming basal texture, while asymmetric rolling can improve formability by inclining the c-axis of hcp crystal. In this study, the combination rolling consisting of symmetric and asymmetric hot rolling has been performed to simultaneously improve formability and maintain high strength of AZ31 magnesium alloy sheet. The symmetrically/asymmetrically combination hot-rolled and annealed sheet exhibits a broadened texture having double peaks with tilt angles of 0º and 40º from ND toward RD with respect to the c-axis. Correspondingly, this sheet shows relatively high yield strength of 123 MPa and large elongation of 24.7%. As for cup drawing test, the conventional warm-rolled sheet is barely formed at 175 °C, but the symmetrically/asymmetrically combination rolled sheet can be formed at temperature as low as 75 °C. These results indicate that the symmetric/asymmetric combination hot-rolling leads to a unique texture with good balance of formability and strength.

Effect of Sn Addition on Corrosion Properties of As-Cast and Hot-Rolled AZ31 Magnesium Alloys

2017 ◽  
Vol 750 ◽  
pp. 124-128
Author(s):  
Yunus Turen ◽  
Didem Güzel ◽  
Huseyin Zengin ◽  
Yavuz Sun ◽  
Hayrettin Ahlatci
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Hot Rolling ◽  
Rolling Process ◽  
Az31 Magnesium Alloy ◽  
Corrosion Properties ◽  
Electric Resistance Furnace ◽  
Hot Rolling Process ◽  
Working Solution ◽  
Hot Rolled

In this study, the effect of Sn addition on corrosion resistance of as-cast and hot rolled AZ31 magnesium alloy was investigated. Sn additions were made by 0.2 wt%, 0.5 wt% and 1 wt%. An electric resistance furnace was used to produce alloys. Hot rolling process was performed at 350 °C by 40% thickness reduction at one rolling pass. Microstructure characterizations were performed by optical (OM) and scanning electron microscope (SEM). Immersion tests and electrochemical analyses were performed to investigate the corrosion resistance of the alloys. A 3.5% NaCl working solution at room temperature was used in both corrosion tests. The results showed that Sn addition decreased the primary dentrite size and restricted the growth of secondary dentritic arm. The as-cast structures transformed to dynamically recrystallized grain structures after hot-rolling process in all the alloys. Corrosion resistance of AZ31 magnesium alloy tended to decrease with Sn addition. This decrease was more clear in homogenized and hot-rolled states while there were some flactuations in as-cast states.

Effect of High Density Electropulsing Current on Microstructure and Mechanical Properties of Fe-6.5wt.%Si Alloy Sheet

2017 ◽  
Vol 898 ◽  
pp. 1236-1241 ◽  
Author(s):  
Y.Y. Liu ◽  
Y.F. Liang ◽  
S.B. Wen ◽  
Feng Ye ◽  
J.P. Lin
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rolling Process ◽  
High Energy ◽  
Alloy Sheet ◽  
High Density ◽  
Rolled Sheet ◽  
Microstructure And Mechanical Properties ◽  
Conventional Heat Treatment ◽  
Hot Rolled

Fe-6.5wt.%Si alloy is an excellent soft magnetic material. Due to the appearance of ordering structures, the alloy shows poor ambient temperature ductility, and can only be cold rolled by specific rolling process. The rolling process with heat treatment is complex and time consuming. Meanwhile, high-energy electropulsing shows electroplastic effect. Heat treatment effect of the high-density electropulsing on microstructure and mechanical properties were investigated. The hot rolled sheet with 1 mm in thickness could be uniformly recrystallized in 33 s at 690 oC by appropriate high density pulses and the ductility was improved in comparison to the conventional heat treatment in a furnace. After the electropulsing treatment, the hot rolled sheet could be warm rolled by 50% reduction of the thickness after one pass without edge crack.

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