Grain Refinement in Magnesium Alloy AZ31 during Multidirectional Forging under Decreasing Temperature Conditions

2005 ◽  
pp. 597-600
Author(s):  
Jie Xing ◽  
Xu Yue Yang ◽  
Hiromi Miura ◽  
Taku Sakai
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Alloy Az31 ◽  
Multidirectional Forging ◽  
Magnesium Alloy Az31 ◽  
Temperature Conditions

Grain Refinement in Magnesium Alloy AZ31 during Multidirectional Forging under Decreasing Temperature Conditions

2005 ◽  
Vol 488-489 ◽  
pp. 597-600 ◽  
Author(s):  
Jie Xing ◽  
Xu Yue Yang ◽  
Hiromi Miura ◽  
Taku Sakai
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Structural Changes ◽  
Large Strains ◽  
Kink Bands ◽  
Alloy Az31 ◽  
Multidirectional Forging ◽  
Magnesium Alloy Az31 ◽  
Cumulative Strain ◽  
Uniform Generation

Grain refinement in a magnesium alloy AZ31 was studied in multi-directional forging (MDF) at a strain rate of 3×10-3s-1 with decreasing temperature from 623K to 423K. The MDF was carried out up to large cumulative strains with changing the loading direction during decreasing temperature from pass to pass. The structural changes were characterized by generation of many mutually crossing kink bands at low strains, followed by development of very fine grains at large strains. The results showed that MDF with decreasing temperature can accelerate uniform generation of much finer grains, resulting in the minimal grain size of 0.36µm in a cumulative strain of 4.8 at 423K. The mechanism of grain refinement was discussed.

Grain Refinement of Magnesium Alloy AZ31 under Torsion Extrusion with a Square-Hole Die

2010 ◽  
Vol 654-656 ◽  
pp. 711-714 ◽  
Author(s):  
Susumu Mizunuma ◽  
Takamichi Iizuka ◽  
Kazuhiro Mitsui ◽  
Hidehito Okumura ◽  
Masahide Kohzu
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Cross Section ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Entire Cross Section ◽  
Extrusion Axis ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31 ◽  
Square Hole

Grain refinement and crystal orientation of magnesium alloy AZ31 under torsion extrusion with a square-hole die are investigated. The optimum temperature and ratio of the die rotation speed to the extrusion speed were clarified, resulting in uniformly distributed fine grains with sizes in the range 1- m over the entire cross section of the worked specimen. The crystal orientation of the specimen was determined by electron backscatter diffraction and compared with that of a conventionally extruded specimen. In the case of torsion extrusion, a very strong <0001> texture was observed along the extrusion axis, especially in the center region of the cross section. In contrast, the <0001> direction of many grains in the conventionally extruded specimen tended to be perpendicular to the extrusion axis.

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).

Strain-Induced Grain Refinement in Magnesium Alloy AZ31 during Hot Forging

2006 ◽  
Vol 503-504 ◽  
pp. 521-526 ◽  
Author(s):  
Xu Yue Yang ◽  
Jie Xing ◽  
Hiromi Miura ◽  
Taku Sakai
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Structural Changes ◽  
Hot Forging ◽  
Kink Bands ◽  
Alloy Az31 ◽  
Continuous Dynamic Recrystallization ◽  
Magnesium Alloy Az31 ◽  
Average Grain Size ◽  
Continuous Dynamic

Strain-induced grain refinement in a magnesium alloy AZ31 was studied in multi-directional forging (MDF) at a temperature range from 423K to 623K and at a strain rate of 3x10-3s-1. MDF with a pass strain of 0.8 was carried out to high cumulative strains of around 5 with changing of the loading direction during decreasing temperature from pass to pass. The structural changes can be characterized by the evolution of many mutually crossing kink bands at low strains followed by increase in their number and misorientation, finally resulting in a fully developed fine-grains at high strains. MDF with decreasing temperature can accelerate the evolution of much finer grains and the improvement of plastic workability. An average grain size of 0.3 μm is formed at an accumulative strain of 4.8 and at 423K. It is concluded that grain refinement under MDF conditions occurs by a series of deformation-induced continuous reactions; that is essentially similar to continuous dynamic recrystallization (cDRX).

Effect of grain refinement on superplastic forming of magnesium alloy AZ31 under three different conditions using rectangular die

2020 ◽  
Vol 22 ◽  
pp. 364-369
Author(s):  
R.B. Raj Kumar ◽  
Mohamed Yameen Ismail ◽  
V. Sonia Vijayarasi ◽  
V.S. Senthil Kumar
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Superplastic Forming ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31
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