scholarly journals Effects of Initial Precipitate on Shear Deformation during Asymmetric Rolling of Al-Mg-Si Alloy: Texture and Formability

2020 ◽  
Vol 58 (10) ◽  
pp. 703-714
Author(s):  
Wonkee Chae ◽  
Bong-Kyu Kim ◽  
Jongbeom Lee ◽  
Jun Hyun Han

Al-Mg-Si alloy was rolled asymmetrically at several temperatures to apply shear deformation, and the effects of the initial precipitate on shear deformation, texture evolution, formability, and plastic anisotropy were studied. Texture was analyzed using a EBSD, and the formability and plastic anisotropy of the specimen were evaluated using the value and value calculated from the plastic strain ratio (r-value) which was determined from the change in the length of the specimen during tensile deformation. Asymmetric rolling induces a larger equivalent strain than symmetric rolling, and the equivalent strain increases as the asymmetric rolling temperature increases. When a specimen with peak-aged initial precipitates was asymmetrically rolled, less shear deformation occurred at room temperature than in a solution-treated specimen without initial precipitates. In contrast, a larger shear deformation occurred at high temperatures (500°C). With asymmetric rolling at room temperature, the specimens without initial precipitates had higher formability and lower plasticity, while for asymmetric rolling at high temperature, the specimens with initial precipitates had higher formability and lower plastic anisotropy. This is due to the <111>//ND texture, such as {111}<110> and {111}<112> orientation that has similar and high r-values at 0°, 45°, and 90° to the rolling direction, developed by the shear deformation that occurred during asymmetric rolling.

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 156 ◽  
Author(s):  
Jakob Kraner ◽  
Peter Fajfar ◽  
Heinz Palkowski ◽  
Goran Kugler ◽  
Matjaž Godec ◽  
...  

The impact of asymmetric cold rolling was quantitatively assessed for an industrial aluminum alloy AA 5454. The asymmetric rolling resulted in lower rolling forces and higher strains compared to conventional symmetric rolling. In order to demonstrate the positive effect on the mechanical properties with asymmetric rolling, tensile tests, plastic-strain-ratio tests and hardness measurements were conducted. The improvements to the microstructure and the texture were observed with a light and scanning electron microscope; the latter making use of electron-backscatter diffraction. The result of the asymmetric rolling was a much lower planar anisotropy and a more homogeneous metal sheet with finer grains after annealing to the soft condition. The increased isotropy of the deformed and annealed aluminum sheet is a product of the texture heterogeneity and reduced volume fractions of separate texture components.


2014 ◽  
Vol 591 ◽  
pp. 55-59 ◽  
Author(s):  
D. Loganathan ◽  
A. Gnanavelbabu

Formability of AA6061 T4 mainly depends upon the physical and mechanical properties of the materials. This study focuses on the effect of annealing at different soaking temperature with furnace cooling conditions. Effects are investigated at three orientations 0o, 45o, and 90o to the rolling direction of sheet metal. The value of plastic strain ratio and strain hardening exponent at three orientations were evaluated.


2010 ◽  
Vol 654-656 ◽  
pp. 1255-1258 ◽  
Author(s):  
Dmitry Orlov ◽  
Rimma Lapovok ◽  
László S. Tóth ◽  
Ilana B. Timokhina ◽  
Peter D. Hodgson ◽  
...  

As-received hot-rolled 5.6 mm thick IF steel sheet was symmetrically/asymmetrically cold rolled at room temperature down to 1.9 mm. The asymmetric rolling was carried out in monotonic (an idle roll is always on the same side of the sheet) and reversal (the sheet was turned 180º around the rolling direction between passes) modes. Microstructure, texture and mechanical properties were analysed. The observed differences in structure and mechanical properties were modest, and therefore further investigation of the effects of other kinds of asymmetry is suggested.


1990 ◽  
Vol 5 (3) ◽  
pp. 484-487 ◽  
Author(s):  
S. R. Nishitani ◽  
M. H. Oh ◽  
A. Nakamura ◽  
T. Fujiwara ◽  
M. Yamaguchi

Polysynthetically twinned crystals of TiAl with a nearly stoichiometric composition have been grown and rolled at room temperature. The maximum total reduction in thickness which is attainable without fracture depends on lamellae orientation with respect to the rolling plane and rolling direction. When specimens are oriented such that shear deformation parallel to the lamellar planes is operative during rolling and its operation causes lengthening of specimens, such specimens can be rolled up to about 50% reduction in thickness. The (111) pole figures are determined for the surface of specimens rolled to several different amounts of reduction, and the formation of surface texture is briefly discussed.


2008 ◽  
Vol 584-586 ◽  
pp. 327-332 ◽  
Author(s):  
Yun Long Chen ◽  
Ai Dang Shan ◽  
Jian Hua Jiang ◽  
Yi Ding

Asymmetric rolling has been considered as a possible way to obtain severe plastic deformation (SPD) since it will give an extra shear deformation to the processed materials during rolling. Previous researches have confirmed such a shear deformation. Very recently, the method of inserting-block is used to characterize the shear deformation through direct observation, but when the reduction is more than 70%, the lineation scratched on the side face of internal mark becomes vague and illegible. In order to directly observe the shear deformation of metallic material with large reduction, the internal mark method is employed in this research and asymmetric rolling was performed with pure aluminum and iron at room temperature. In severe plastic deformation, the shear deformation caused by asymmetric rolling was clearly observed and measured through employing internal mark method. Remarkable extra shear deformation during asymmetric rolling was confirmed. Very high equivalent strains were achieved when sheet samples were asymmetrically rolled to high reduction ratio. These strain values fall into the range of SPD.


2013 ◽  
Vol 765 ◽  
pp. 363-367
Author(s):  
Ekta Jain ◽  
Uday Chakkingal

Aluminium alloy sheets have poor drawability compared to steel sheets as indicated by the values of the plastic strain ratio or the R value. Because of the textures developed during commercial annealing and cold rolling processes, the R value for aluminium alloys is typically less than 1. Since the R value is heavily influenced by the crystallographic texture in the sheet, processes that develop a favourable texture can be utilised to improve the R value. In this study, a severe plastic deformation process called groove pressing has been used to repeatedly deform sheet specimens of aluminium alloy AA 5052. The R values of groove pressed specimens were experimentally determined. X-ray diffraction scans of the groove pressed specimens were carried out to measure the relative intensities of (111) and (002) peaks in the pattern. The largest increase in the R value was for specimens cut at 90° to the rolling direction and groove pressed to four passes. XRD data indicate that the groove pressing process is capable of introducing a favourable shear texture.


2016 ◽  
Vol 835 ◽  
pp. 203-209 ◽  
Author(s):  
Su Kwon Nam ◽  
In Soo Kim ◽  
Dong Nyung Lee

The average plastic strain ratio (the R-value) and the anisotropy parameter |ΔR| calculated from the measured texture of AA1050 Al alloy sheet treated by the heavy asymmetric rolling by 84% reduction in thickness and subsequent annealing for 1 h at 500 °C, followed by light rolling by 10% or 20% reduction in thickness and the subsequent annealing for 1 h at 500 °C increased by 1.52 times that of the non-processed specimen and reduced to 1/12 times that of the non-processed specimen, respectively.


2014 ◽  
Vol 886 ◽  
pp. 3-6
Author(s):  
Zu Jian Yu ◽  
Jian Hui Li ◽  
Yan Yang

Tensile tests and a cold deep drawing process were developed at room temperature to estimate the stamping formability of AZ31B magnesium alloy sheet. The results show that AZ31B magnesium alloy sheet has poor formability at room temperature with the total elongation of ~ 20%, the yield ratio is about 0.6 and the strain-hardening exponent is 0.18, while the plastic strain ratio is 1.58, and the earing ratio is-0.55.Thus, AZ31B magnesium alloy sheet can not suffer server plastic deformation. It was found that comparatively shallow magnesium alloy cups were satisfactorily formed at room temperature without heating when the punch fillet radius 6mm and the die fillet radius10mm with a 1mm thickness sheet with limit drawing ratio of 1.25.


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