Effect of Reduction Rate on the Recrystallization Behavior in AA3003 Aluminum Alloy Fabricated by DC Casting

2021 ◽  
Vol 1034 ◽  
pp. 17-22
Author(s):  
Sung Jin Park ◽  
Shinji Muraishi
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Grain Boundary ◽  
Rolling Direction ◽  
Reduction Rate ◽  
Xrd Analysis ◽  
Recrystallization Behavior ◽  
Deformation Bands ◽  
Cold Rolled ◽  
Apparent Activation Energies

The recrystallization behavior of the cold-rolled AA3003 aluminum alloy with the reduction rate of 20%, 50% and 90% during annealing at the temperature ranging from 300°C to 400°C was investigated. As increasing reduction rate, the cold rolled specimens exhibit deformation bands with elongated grain microstructure consisting of straight grain boundary parallel to rolling direction. Therefore, large density of nucleation sites for recrystallization would be expected with increase of strain energy. The grain size of the cold-rolled specimens decreased with increase of reduction rate, c.f., as the rolling reduction increased to 90%, grain size along the direction normal to the sheet decreased to about 8μm in thick. When the sample annealed at 350°C for 5s, the first recrystallized grains were observed in the vicinity of the grain boundary. The relaxation and recrystallization kinetics under different annealing conditions were characterized in terms of the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model. The apparent activation energies of recrystallization for the cold-rolled specimens with reduction rate of 20%, 50% and 90% were determined as 332 kJ/mol, 239 kJ/mol and 115 kJ/mol, respectively. XRD analysis by using modified Williamson–Hall plots revealed that the tendency of the change in dislocation density is varied depending on reduction rate. These results indicate that the apparent activation energy for recrystallization and the crystallites size decrease with increase of the reduction rate, which leads to a decrease in the size of the recrystallized grains.

Boron and Phosphorus Segregation Behavior at Grain Boundary in a Ti-If Steel after Annealing

2010 ◽  
Vol 152-153 ◽  
pp. 320-325 ◽  
Author(s):  
Xin Li Song ◽  
Ze Xi Yuan ◽  
Juan Jia ◽  
Ping He Li ◽  
Di Wang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Rolling Direction ◽  
Optical Microscope ◽  
If Steel ◽  
Microstructure Development ◽  
Rolled Sample ◽  
Phosphorus Segregation ◽  
Segregation Behavior ◽  
Cold Roll ◽  
Cold Rolled

The cold roll B-added Ti-IF steel is annealed for different times at 810 oC. The microstructure development is studied by Optical Microscope（OM） and the concentration of boron and phosphorus segregation at grain boundary is measured by Auger electron spectroscopy（AES）. The result shows that the grain of the cold- rolled sample is elongated along the rolling direction and the elongated grains become into equi-axis shape after annealing 60 to 180sec. Boron and phosphorus segregated at gain boundaries. But boron’s concentration at grain boundary is higher than that of phosphorus and increase from 5at.% or so to about 10at% after annealing 150sec, Then boron’s concentration decrease slowly to 8at.% at 240sec. While phosphorus’s concentration increase to the max of 2.5at.% or so at 120sec, then its concentration decrease to 1at.% or so after annealing 240sec.

Effect of Cold Reduction Rate on Ferrite Recrystallization Behavior during Annealing in Low-Carbon Steel with Different Initial Microstructures

2021 ◽  
Vol 1016 ◽  
pp. 1045-1050
Author(s):  
Toshio Ogawa ◽  
Ryo Hishikawa ◽  
Yoshitaka Adachi
Keyword(s):  
Carbon Steel ◽  
Reduction Rate ◽  
Low Carbon Steel ◽  
Cold Reduction ◽  
Rolled Sheet ◽  
Recrystallization Behavior ◽  
Low Carbon ◽  
Dislocation Densities ◽  
Cold Rolled ◽  
Hot Rolled

We investigate the effect of the cold reduction rate on ferrite recrystallization behavior during the annealing of low-carbon steel with different initial microstructures. Three types of hot-rolled sheet specimens are prepared: specimens P, B, and M, which consist of ferrite and pearlite, bainite, and martensite, respectively. To evaluate the effect of the cold reduction rate on ferrite recrystallization behavior, hot-rolled sheet specimens are cold-rolled at cold reduction rates of 40% and 67%. The cold-rolled sheet specimens are heated to the target temperature, and then water-quenched to room temperature. Irrespective of the initial microstructures, the ferrite recrystallization is accelerated by increasing the cold reduction rate. In addition, the dislocation densities of specimens P and B increase at the larger cold reduction rate, which accelerates ferrite recrystallization in these specimens. In the case of specimen M, the dislocation arrangement parameter remarkably decreases at the larger cold reduction rate, whereas the dislocation density hardly changes. Thus, we conclude that the accelerated ferrite recrystallization at the larger cold reduction rate for specimen M can be mainly attributed to an increase in the amount of interactions between dislocations in the specimen.

On {h,1,1}, the Recrystallisation Texture of Heavily Cold Rolled BCC Steel

2004 ◽  
Vol 467-470 ◽  
pp. 269-274 ◽  
Author(s):  
Hotaka Homma ◽  
Shuichi Nakamura ◽  
Naoki Yoshinaga
Keyword(s):  
Grain Boundary ◽  
Cold Rolling ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Rolling Direction ◽  
Experimental Results ◽  
Rolled Steel ◽  
Fibre Structure ◽  
Pole Figures ◽  
Cold Rolled

Heavily cold rolled BCC steel has been indicated to generate {411}<148> recrystallisation texture and its family orientations which might be represented as {h,1,1}<1/h,1,2>. As a-fibre structure, or RD//<011> texture is significantly developed during the cold rolling, it is naturally speculated to be the recrystallisation site of {h,1,1}<1/h,1,2> fibre. The present paper prompts to demonstrate the recrystallisation procedure by utilising EBSP-OIM analysis. The first demonstration was carried out with OIM analysis on partially recrystallised cold rolled steel. At the stage of 50% recrystallisation, only ND//<111> texture has appeared for the recrystallised area. {100}<011> - {211}<011> a-fibre remains as deformed structure, and several {h,1,1}<1/h,1,2> grains could be found at the grain boundaries. Therefore, a bi-crystal of {100}<011> was employed to simulate the irregular deformation at the grain boundary. After cold rolling, a warp toward the grain boundary was observed. Although the interior of the {100}<011> single crystal was hardly recrystallised, sharp {411}<148> texture was created along the grain boundary. In order to confirm the phenomenon, another experiment was carried out that a cold rolled {100}<011> single crystal was bent along the rolling direction and annealed. Very sharp {411}<148> recrystallisation texture was formed again at the bent perimeter. These experimental results lead us to conclude that the irregular strain was sufficiently piled at the grain boundary after the heavy deformation and generates {h,1,1}<1/h,1,2> texture. On {100} pole figures, the recrystallisation textures were equivalently scattered around three <100> poles, therefore the rotation relationship around <111> axes with the original orientation was suggested.

Effect of Rolling Direction on the Microstructure and Mechanical Properties of Accumulative Roll Bonding (ARB) Processed Commercially Pure 1050 Aluminum Alloy

2006 ◽  
Vol 503-504 ◽  
pp. 681-686 ◽  
Author(s):  
Yong Suk Kim ◽  
Suk Ha Kang ◽  
Dong Hyuk Shin
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Tensile Elongation ◽  
Rolling Direction ◽  
Rolled Plate ◽  
Al Alloy ◽  
Cycle Number ◽  
Average Grain Size ◽  
Number Of Cycles ◽  
1050 Aluminum Alloy

The cross-ARB (C-ARB) process, which adopts cross rolling of the two stacked plates, has been performed up to seven cycles on a commercial purity 1050 aluminum alloy to obtain ultrafine grains with an average grain size of 0.7μm. Microstructural evolution of the C-ARB processed aluminum alloy was examined by a transmission electron microscopy as a function of process cycle number (accumulated plastic strain). Tensile property of the severely deformed Al alloy was also explored. Grain size of grains of the C-ARB processed alloy varied across thickness of the rolled plate. The size of grains at the top and bottom of the rolled plate converged to 0.65μm, while that of grains at the center of the plate increased with the number of ARB cycles. Tensile strength of the CARB processed 1050 Al alloy increased from 100MPa (as-received) to 160MPa. Tensile elongation varied with the number of cycles, but 15% of failure strain was measured from the 6-cycle C-ARB processed specimen. The variation of the elongation with the cycle number coincided exactly with the variation of grain size at the center of the processed plate.

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