Microstructural Changes with Annealing of a Nanostructured Al Alloy Severely Plastic Deformed by Four-Layer Stack Accumulative Roll-Bonding Process

2020 ◽  
Vol 20 (7) ◽  
pp. 4419-4422
Author(s):  
Seong-Hee Lee
Keyword(s):  
Aluminum Alloy ◽  
Annealing Temperature ◽  
Rolling Direction ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Heterogeneous Structure ◽  
Microstructural Changes ◽  
Ultrafine Grained ◽  
Coarse Grains ◽  
Ultrafine Grained Microstructure

Microstructural changes with annealing of a nanostructured complex aluminum alloy fabricated by 3 cycles of four-layer stack ARB process using different Al alloys were investigated in detail. The four-layer stack ARB process using AA1050, AA5052 and AA6061 alloy sheets was performed up to 3 cycles without a lubricant at room temperature. The sample fabricated by the ARB is a multi-layer aluminum alloy sheet in which the AA1050, AA5052 and AA6061 aluminum alloys are alternately stacked to each other. The layer thickness of each alloy became thinner and elongated to the rolling direction with the number of ARB cycles. The grain size decreased with increasing of the number of ARB cycles, and became about 160 nm in thickness after 3 cycles. The complex Al alloy still showed ultrafine grained microstructure to annealing temperature of 300 °C, but it had a heterogeneous structure containing both the ultrafine grains and the coarse grains due to an occurrence of discontinuous recrystallization after 350 °C.

Research on Synchronized Cooling Hot Forming Process of 6016 Aluminum Alloy

2012 ◽  
Vol 452-453 ◽  
pp. 81-85 ◽  
Author(s):  
Ming He Chen ◽  
Y.Y. Cao ◽  
W. Chen ◽  
Guo Liang Chen
Keyword(s):  
Aluminum Alloy ◽  
Process Parameters ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Alloy Sheet ◽  
Hot Forming ◽  
Al Alloy ◽  
Forming Process ◽  
Process Step ◽  
6016 Aluminum Alloy

In order to improve formability of high strength Al-alloy sheet metal, in this paper, it come up with the synchronized cooling hot forming process. Taking the aluminum alloy of 6016 H18 aluminum alloy, which carried out its technology test by Gleeble3500 hot-mechanical simulator. The process parameters such as deformation temperature T, holding time t and cooling rate v is investigated by the orthogonal test and the microstructure is analyzed simultaneously. The results show that the synchronized cooling hot forming process can be applied to 6016 H18 aluminum alloy, it both improves the formability of 6016 H18 aluminum alloy significantly and obtains the high strength after forming, it can meet the purpose of implementing deformation and enhanced in one process step, the proper combination of process parameters are T=450 °C, t=210 s, v=60 °C/s. Strengthening mechanism is which there is a large number of strengthening phase precipitated from matrix in technology process, the strengthening phases are coarser and the dispersed uniformity is a bit worse compared with that of T4 state.

Microstructural Evolution and Mechanical Properties of Ultrafine Grained Commercially Pure 1100 Aluminum Alloy Processed by Accumulative Roll-Bonding (ARB)

2004 ◽  
Vol 449-452 ◽  
pp. 625-628 ◽  
Author(s):  
Yong Suk Kim ◽  
T.O. Lee ◽  
Dong Hyuk Shin
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Microstructural Evolution ◽  
Sliding Wear ◽  
Al Alloy ◽  
Commercially Pure ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Accumulated Strain

The ARB process has been carried out up to seven cycles on a commercial purity 1100 aluminum alloy to obtain ultra-fine grains with the average grain size of 500 nm. Microstructural evolution of the ARB processed aluminum alloy was examined by a transmission electron microscopy as a function of accumulated total strain. Mechanical properties including hardness, tensile property, and sliding wear characteristics of the severely deformed Al alloy were also investigated. Grain boundaries of the ARB processed alloy were diffusive and poorly defined after the initial ARB cycles, however they changed to well-defined high angle boundaries with the increase of the accumulated strain. Though hardness and strength of the ARB processed alloy were enhanced significantly, wear resistance of the processed alloy hardly increased. The mechanical properties were discussed in connection with the microstructure.

scholarly journals Improvement of Pitting-Corrosion Resistance of Ultrafine-Grained 7475 Al Alloy by Aging

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 360
Author(s):  
Ewa Ura-Bińczyk
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Al Alloy ◽  
Subsequent Aging ◽  
Fine Grained ◽  
Transmission Electron ◽  
Pitting Corrosion Resistance ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure

The effect of aging on the resistance to pitting corrosion of ultrafine-grained 7475 aluminium (Al) alloy processed by hydrostatic extrusion (HE) is studied. Differences in the microstructure were investigated using secondary electron (SEM) and transmission electron microscopy (TEM). Corrosion tests were performed in 0.1 M NaCl, and characterization of corroded surface was performed. The results of this work show that the pitting susceptibility of ultra-fine grained 7475Al is related to the distribution of MgZn2 precipitates. After HE, the formation of An ultrafine-grained microstructure at the grain boundaries of ultrafine grains is observed, while subsequent aging results in the formation of MgZn2 precipitates in the grain interior. Grain refinement increases susceptibility to localized attack, while the subsequent aging improves the overall corrosion resistance and limits the propagation of corrosion attack.

scholarly journals Enhanced Stretch Formability of AZ31 Magnesium Alloy Thin Sheet by Induced Precompression and Sequent Annealing

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1401 ◽  
Author(s):  
Lifei Wang ◽  
Bo Song ◽  
Zhengyong Zhang ◽  
Hua Zhang ◽  
Tingzhuang Han ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thin Sheet ◽  
Annealing Treatment ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Coarse Grains ◽  
Stretch Formability ◽  
Strength And Ductility

In this study, precompression deformation with a strain level of 5.38% along the transverse direction (TD) at room temperature was conducted on a AZ31 magnesium alloy thin sheet with thickness of 1mm. Then subsequent annealing treatment was carried out at various temperatures (200, 300, 400, and 500 °C) to induce static recrystallization (SRX) and grain growth. The stretch formability was also investigated using the hemispherical test. The results showed that the twinning texture induced by the precompression process was nearly inherited by recrystallized grains after annealing process. Grains grew up and the size increased with the increase of annealing temperature. The largest grain size was obtained when annealing at 400 °C. The mechanical properties including strength and ductility decreased due to the development of coarse grains, however, the stretch formability was enhanced significantly. Indeed, the IE-value increased from 2.83 mm in the as-received Mg alloy sheet to 5.78 mm in the precompressed and 400 °C annealed specimens, leading to an improvement of 104%. This was ascribed to the rotated grain orientation and higher activity of (10–12) twins in coarse grains.

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.

Texture Change of Severe Plastically Deformed Al Alloy Sheets

2010 ◽  
Vol 654-656 ◽  
pp. 1259-1262 ◽  
Author(s):  
In Soo Kim ◽  
Su Kwon Nam ◽  
Saidmurod Akramov
Keyword(s):  
Aluminum Alloy ◽  
Low Carbon Steel ◽  
Sheet Thickness ◽  
Deformation Texture ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Low Carbon ◽  
Asymmetric Rolling ◽  
Heat Treated ◽  
Texture Change

Aluminum alloy sheets have lower formability (r-value) than low carbon steel sheets in fully annealed condition. Because the texture of fully annealed aluminum alloy sheet is mainly consists of cube component {001}<100>, which shows low formability. Asymmetric rolling, one of the severe plastic deformations, gives rise to shear deformation texture through the Al sheet thickness. In this paper, the changes of texture components after the severe deformation and subsequent heat treatment in Al sheet were observed. The change of the formability after the severe plastic deformation and subsequent heat-treated Al sheets have been analyzed with the change of texture of Al alloy sheets.

scholarly journals Effects of Annealing and Deformation on Sagging Resistance of a Hot-Rolled, Four-Layered Al Alloy Clad Sheet

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Minglong Kang ◽  
Li Zhou ◽  
Yunlai Deng ◽  
Jinqin Lei
Keyword(s):  
Annealing Temperature ◽  
Reduction Rate ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Composite Sheet ◽  
Aluminum Composite ◽  
The Core ◽  
Clad Sheet ◽  
Lower Temperature ◽  
Hot Rolled

Multilayer brazeable aluminum alloy sheet is prone to collapse during high-temperature brazing process. The sagging resistance of the aluminum composite sheet needs to be further improved for quality control. Effects of annealing and rate of reduction on sagging resistance, microstructure, and Si diffusion of a hot-rolled, four-layered Al clad sheet (4343/3003/6111/3003) were investigated by means of a sagging device, OM, SEM, and TEM. Results showed that once annealed at 360°C, the sagging distance was increased from 3 to 15.7 mm as the reduction rate changed from 10% to 40%. By increasing annealing temperature to 410°C, those were changed from 3.1 to 20.8 mm accordingly. At 360°C/40% and 410°C/40%, specimens exhibited weak sagging resistance, whereas fine recrystallized grains were formed in the core promoting Si penetration along grain boundaries. While the specimens were treated at 360°C/10% and 410°C/10%, better sagging resistance was observed due to the formation of coarse recrystallized grains that can suppress erosion of Si. At the same reduction rate, the sagging resistance was higher for the sample annealed at a lower temperature as more precipitates appeared in the core (at 360°C), thus leading to an increase in strength.

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