A novel continuous squeeze casting-extrusion process for grain refinement and property improvement in AZ31 alloy

2021 ◽  
Vol 808 ◽  
pp. 140942
Author(s):  
Dijia Zhao ◽  
Shulin Lü ◽  
Jianyu Li ◽  
Wei Guo ◽  
Shusen Wu
Keyword(s):  
Grain Refinement ◽  
Squeeze Casting ◽  
Az31 Alloy ◽  
Extrusion Process

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.

Grain Refinement and Texture Evolution in AZ31 Alloy during ECAP Process and Their Effects on Mechanical Properties

2005 ◽  
Vol 475-479 ◽  
pp. 549-554 ◽  
Author(s):  
H.S. Kim ◽  
Hyo Tae Jeong ◽  
Ha Guk Jeong ◽  
Woo Jin Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Refinement ◽  
Texture Evolution ◽  
Az31 Alloy ◽  
Mg Alloys ◽  
Fine Grained ◽  
Ecap Process ◽  
Texture Modification ◽  
Similar Texture

The softening of fine-grained ECAPed AZ31 Mg alloys could be ascribed to the texture modification during ECAP. Lower ECAP temperature is more effective in refining the microstructure. The strength of the ECAPed AZ 31 Mg alloys increased with decrease in grain size when they have similar texture.

scholarly journals Effects of Carbon and/or Alkaline Earth Elements on Grain Refinement and Tensile Strength of AZ31 Alloy

2008 ◽  
Vol 49 (10) ◽  
pp. 2303-2309 ◽  
Author(s):  
Jun Du ◽  
Jian Yang ◽  
Mamoru Kuwabara ◽  
Wenfang Li ◽  
Jihua Peng
Keyword(s):  
Tensile Strength ◽  
Grain Refinement ◽  
Alkaline Earth ◽  
Az31 Alloy ◽  
Alkaline Earth Elements

Influence of number of ECAP passes on microstructure and mechanical properties of AZ31 magnesium alloy

2012 ◽  
Vol 57 (3) ◽  
pp. 711-717 ◽  
Author(s):  
K. Bryła ◽  
J. Dutkiewicz ◽  
L. Litynska-Dobrzynska ◽  
L.L. Rokhlin ◽  
P. Kurtyka
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Vickers Microhardness ◽  
Az31 Alloy ◽  
Az31 Magnesium Alloy ◽  
Angular Pressing ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron

The aim of this work was to investigate the influence of the number of equal channel angular pressing (ECAP) passes on the microstructure and mechanical properties of AZ31 magnesium alloy. The microstructure after two and four passes of ECAP at 423 and 523 K was investigated by means of optical and transmission electron microscopy. The mechanical properties were carried out using Vickers microhardness measurements and compression test. The grain refinement in AZ31 alloy was obtained using ECAP routes down to 1,5 μm at 423 K. Processes of dynamic recrystallization during ECAP were observed. It was found that a gradual decrease of grain size occurs with the increasing of number of ECAP passes. The grain refinement increases mechanical properties at ambient temperature, such as Vickers microhardness and compression strength proportionally to d-0.5.

The Effect of Manganese on the Grain Size of Commercial AZ31 Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 139-142 ◽  
Author(s):  
Peng Cao ◽  
David H. StJohn ◽  
Ma Qian
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Electron Microprobe ◽  
Az31 Alloy ◽  
Long Period ◽  
Intermetallic Particles ◽  
Nucleation Sites

The effect of manganese on grain refinement of a commercial AZ31 alloy has been investigated using an Al-60%Mn master alloy splatter as an alloying additive at 730 °C in aluminium titanite crucibles. It is shown that grain refinement by manganese is readily achievable in AZ31. Electron microprobe analyses reveal that prior to the addition of extra manganese the majority of the intermetallic particles found in AZ31 are of the Al8Mn5 type. However, after the addition of extra manganese in the range from 0.1% to 0.8%, the predominant group of intermetallic particles changes to the metastable AlMn type. This leads to a hypothesis that the metastable AlMn intermetallic particles are more effective than Al8Mn5 as nucleation sites for magnesium grains. The hypothesis is supported by the observation that a long period of holding at 730 °C leads to an increase in grain size, due probably to the transformation of the metastable AlMn to the stable Al8Mn5. The hypothesis has also been used to understand the mechanism of grain refinement by superheating.

Application of a Cold ECAP to Magnesium Alloy (AZ31) by a Combination of Extrusion Process

2005 ◽  
Vol 486-487 ◽  
pp. 313-316 ◽  
Author(s):  
Jae Wan Song ◽  
Hee Taek Lim ◽  
Jeong Whan Han ◽  
Mok Soon Kim ◽  
Sun Keun Hwang
Keyword(s):  
Effective Strain ◽  
Three Dimensional ◽  
Az31 Alloy ◽  
Extrusion Process ◽  
New Combination ◽  
Compressive Yield Strength ◽  
Element Analysis ◽  
Combination Process ◽  
Angular Pressing ◽  
Von Mises

It is well known that magnesium alloys have difficulties in room temperature formability because of their HCP structure. As a basic approach to enhance a cold formability, a new combination process including an extrusion followed by a cold equal channel angular pressing (ECAP) was attempted. ECAP die has an inner die corner angle of 135 degree, the fillet angle of 45 degree and thickness of 5mm. A finite element analysis with a three-dimensional thermo-coupled elasto-plastic model was also carried out to understand the change of stress and strain during ECAP. Experiments showed that the AZ31 alloy, which is extruded at a ratio of 20 and is heat-treated at 350°C, was successful in a cold ECAP. From the simulated results, it was found that the effective strain gradually decreased from the inner die side (0.533) to the outer die side. This was confirmed by the analytical analysis via von Mises criterion. Furthermore, it also matched well with the experiments, which showed a uniform shear deformation band. It was also interesting to note that compressive yield strength was drastically increased, which is caused by the occurrence of numerous twins spread across the materials during a cold ECAP.

Effective Dispersion of CNTs to Fabricate CNT/Mg Nanocomposite

2015 ◽  
Vol 816 ◽  
pp. 470-475 ◽  
Author(s):  
Guo Qiang Han ◽  
Wen Bo Du ◽  
Zhao Hui Wang ◽  
Ke Liu ◽  
Shu Bo Li ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Yield Strength ◽  
Grain Refinement ◽  
Melting Process ◽  
Az31 Alloy ◽  
Alloy Matrix ◽  
Dispersion Process ◽  
Wet Process ◽  
Magnesium Alloy Az31 ◽  
Effective Dispersion

An effective dispersion process to cast CNT-reinforced in a concentrated magnesium alloy (AZ31) nanocomposite was investigated in this study. The metal magnesium powder was first coated with dispersed CNTs by wet process, followed by the fabricating of CNT/Mg precursor using mechanical briquetting and extrusion. The resultant precursor was then added into AZ31 alloy during the melting process. Finally, CNT/Mg nanocomposites with grain refinement matrix composite were fabricated in as-cast and as-extruded. Compared with the commercial AZ31 alloy, CNT/Mg nanocomposites exhibited higher yield strength of 270 MPa with an increase of 22.7%, which can be largely ascribed to the effective dispersion process of CNTs in the alloy matrix, and the elongation is no significant decrease.

The Grain Size Evolution of AZ31 Profiles as a Function of Different Casting Conditions

2005 ◽  
Vol 488-489 ◽  
pp. 349-356 ◽  
Author(s):  
Franka Pravdic ◽  
H. Kilian ◽  
M. Brandecker ◽  
C. Wögerer ◽  
G. Traxler
Keyword(s):  
Grain Size ◽  
Casting Machine ◽  
Az31 Alloy ◽  
Extrusion Process ◽  
Direct Chill ◽  
Mechanical Tests ◽  
Direct Chill Casting ◽  
Metallographic Analysis ◽  
Process Chain ◽  
Chill Casting

The present paper describes the microstructural evolution of AZ31 alloy along the process chain, from the melt treatment, the direct chill casting up to the extrusion process. Each step in the process chain will be considered in order to design the appropriate properties of the endproducts. The research has been done in industrial scale at ARC Leichtmetallkompetenzzentrum Ranshofen GmbH (LKR), in order to analyse the grain size dependency of AZ31 alloy on different casting conditions. The casting trials with and without grain refinement were carried out at the vertical direct chill casting machine MAGNUMCAST®. After the extrusion process metallographic analysis and mechanical tests were carried out.

Grain Refinement by Combined ECAE/Extrusion and Dieless Drawing Processes for AZ31 Magnesium Alloy Tubes

2010 ◽  
Vol 654-656 ◽  
pp. 735-738 ◽  
Author(s):  
Tsuyoshi Furushima ◽  
Tetsuhide Shimizu ◽  
Kenichi Manabe
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Equal Channel Angular Extrusion ◽  
Extrusion Process ◽  
Az31 Magnesium Alloy ◽  
Drawing Process ◽  
Fine Grained ◽  
Tube Extrusion ◽  
Dieless Drawing ◽  
Average Grain Size

Grain refinement processing by severe deformation, combined equal-channel angular extrusion (ECAE) processing and conventional tube extrusion, is applied to AZ31 magnesium alloy. By a combination of ECAE processing and tube extrusion, a fabricated tube, with outer and inner diameters of 2 mm and 1 mm, respectively, has fine, homogeneous, and equiaxed grain structure with an average grain size of 1.5m. Tensile test results indicate that the fine-grained tubes exhibited a superplasticity potential m value of 0.55.The maximum elongation (688%) is obtained at a temperature of 673K. Furthermore, the tubes fabricated by combined ECAE/extrusion process is applied to dieless drawing process without using any tool and die.As a result, dieless drawing limit is enhanced due to high m value achieved by combined ECAE/Extrusion process. From these results, the effectiveness of new grain refinement processing for fabricating fine-grained tubes and its application for dieless drawing process to fabricate the fine tubes was demonstrated experimentally.

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