ARB Process Research Articles

RETRACTED: Characterization of ultrafine-grained aluminum tubes processed by Tube Cyclic Extrusion–Compression (TCEC)

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. The authors have reused part of the following paper authored by Mehdi Eizadjou, Habib Danesh Manesh, Kamal Janghorban: Microstructure and mechanical properties of ultra-fine grains (UFGs) aluminum strips produced by ARB process, Journal of Alloys and Compounds, Volume 474, Issues 1–2, 17 April 2009, Pages 406–415, ISSN 0925-8388, http://dx.doi.org/10.1016/j.jallcom.2008.06.161. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

The effect of alumina content on the mechanical properties of hybrid composites fabricated by ARB process

In the present work, the effect of particle content on the mechanical properties of hybrid composites fabricated by anodizing and accumulative roll bonding processes was investigated. The ARB process was used for the fabrication of the hybrid composite, including different contents of alumina particles. Microstructural observations and fractography were performed by scanning electron microscopy (SEM). Also, the mechanical properties were investigated by tensile and microhardness tests. It was realized that when the number of ARB cycles was increased, uniformity of particles distribution was improved in the aluminum matrix. Also, with increasing the number of cycles, the tensile strength of hybrid composites was increased too. In addition, with increasing the alumina content in the aluminum matrix, the tensile strength and elongation of hybrid composites were increased and decreased, respectively. The ARB-processed hybrid composites exhibited a higher hardness value than that of the annealed sample. Moreover, with increasing the alumina content in the aluminum matrix, the hardness of hybrid composites was increased. It was also found that with increasing the number of cycles, the bond strength of all interfaces was improved and the unbonded regions of the interface were decreased. The hybrid composites after the first and second cycles exhibited a typical ductile fracture showing deep equiaxed dimples, whereas the fracture mode after the fourth cycle was a combination of ductile and shear ductile fracture.

Grain Refinement in the Formability of Aluminium Thin Cup

Refinement of the grain diameter of the micro structure of Aluminium foil with a thickness of 300μm has been done through the ARB process up to fourth cycles with 72 layers that are proven to increase formability in micro forming a cup. Grain size was measured from the full annealed condition, of the ARB process, and the results of ARB process followed by stress relieved. Formability of the formation of a cup which is expressed as the LDR has increased from 1.87 for the material conditions of full annealed to 2.00 for the ARB process followed by stress relieved in a single step process. In addition to improved formability obtained in a cup formation, grain refinement in the microstructure can also reduce cup earing and wrinkle on the cup wall.

ARB공정에 의해 제조한 AA1050/AA5052 복합 알루미늄합금의 기계적 특성

ARB공정에 의해 제조한 AA1050/AA5052 복합 알루미늄합금의 기계적 특성

Microstructure and Texture of a Nano-Grained Complex Al Alloy Fabricated by Accumulative Roll-Bonding of Dissimilar Al Alloys

An ultrafine grain (UFG) complex lamella aluminum alloy sheet was successfully fabricated by ARB process using AA1050 and AA6061. The lamella thickness of the alloy became thinner and elongated to the rolling direction with increasing the number of ARB cycles. By TEM observation, it is revealed that the aspect ratio of UFGs formed by ARB became smaller with increasing the number of ARB cycles. In addition, the effect of ARB process on the development of deformation texture at the quarter thickness of ARB-processed sheets was clarified. ARB process leaded to the formation of the rolling texture with shear texture and weak cube orientation. The subdivision of the grains to the rolling direction began to occur after 3 cycles of the ARB, resulting in formation of ultrafine grains with small aspect ratio. After 5 cycles, the ultrafine grained structure with the average grain diameter of 560 nm develops in almost whole regions of the sample.

Dislocation density and flow stress modeling of nanostructured Al–SiCp composite during accumulative roll bonding

In order to investigate the dislocation structure and flow stress evolution of Al–SiCp composite during ARB process, a comprehensive model which describes the evolution of dislocation density is needed. Dislocation density, microstructure and flow stress evolution of Al–SiCp composite are predicted considering the ETMB model, strain and strain rate achieved from the mechanical model of ARB process and shear modulus calculated from the composite model. In addition, models’ parameters such as dislocation generation parameters are modified due to the effect of SiC particles. The predicted results are in good agreement with experimental data.

Texture Evolution in Al–0.2 mass%Sc Alloy during ARB Process and Subsequent Annealing

Evolution of textures in the solution treated and aged Al­0.2Sc alloy heavily deformed by ARB process and subsequently annealed was investigated using pole figure and orientation distribution functions (ODF) that were determined by electron backscatter diffraction (EBSD) technique. Three kinds of starting materials were prepared before the ARB process: solution treated (ST) material, 300°C-aged material including fine Al3Sc precipitates, and 400°C-aged material having coarse Al3Sc precipitates. The results of deformation texture indicated that at early stage of ARB S {123} h634i orientation component developed and it changed to Copper {112} h111i and Taylor {4411} h11118i components at later ARB cycles in both ST-ARB and Aged-ARB specimens. However, in the Aged-ARB specimens after 5-cycle ARB process, Copper {112} h111i component decreased and Taylor {4411} h11118i component did not developed. Cube {100} h001i component strongly developed in the 400°C Aged-ARB specimen by annealing at high temperature, whereas Cube component did not develop in the ST-ARB and 300°C Aged-ARB specimen. Such a difference was understood as the effect of Al3Sc precipitates. [doi:10.2320/matertrans.MA201223]

Changes in Strength and Microstructure of Cu (100) [001] Single Crystals Caused by Accumulative Roll-Bonding

Plate-like copper single crystals with (100) [001] orientation were subjected up to nine cycles of the ARB process. Ultrafine grains less than 1 µm were obtained in the single crystal ARB processed by six cycles. Changes in strength and microstructure of the ARB processed single crystals are compared with those of the ARB processed polycrystals. Origins of high strength of the ARB processed single crystals are discussed.

Fabrication and Estimation of an Ultrafine Grained Complex Aluminum Alloy Sheet by the ARB Process Using Dissimilar Aluminum Alloys

Fabrication and Estimation of an Ultrafine Grained Complex Aluminum Alloy Sheet by the ARB Process Using Dissimilar Aluminum Alloys

Microstructure and Tensile Properties of Ultrafine Grained Pure Al Sheets Produced by Accumulative Roll Bonding

Usually the heat treatment in the cyclic ARB passes is indispensable to reduce work-hardening effects and improve interface bonding quality. The possibility of accelerating grain refinement of aluminum sheets with a dimension of 300 mm×50 mm×1 mm is investigated during the ARB process at room temperature, in which the samples are rotated by 180 degree around normal plane axis perpendicular to the rolling plane between the adjacent cycles. By means of optical microscopy and transmission electron microscopy, it shows that the bonding interfaces can not obviously observed after five cycles, and grains are refined to be ~0.5 μm. Tensile tests show the ARB samples exhibit strain hardening behavior after yielding without a sudden fracture even up to seven cycles of ARB. The softening behavior and enhanced ductility was explained by dynamic recovery, the recrystallization process and even abnormal large grains.

Mechanical and corrosion resistance of a new nanostructured Ti–Zr–Ta–Nb alloy

In this work, a multi-elementary Ti–10Zr–5Nb–5Ta alloy, with non-toxic alloying elements, was used to develop an accumulative roll bonding, ARB-type procedure in order to improve its structural and mechanical properties. The alloy was obtained by cold crucible semi-levitation melting technique and then was ARB deformed following a special route. After three ARB cycles, the total deformation degree per layer is about 86%; the calculated medium layer thickness is about 13 μm. The ARB processed alloy has a low Young’s modulus of 46 GPa, a value very close to the value of the natural cortical bone (about 20 GPa). Data concerning ultimate tensile strength obtained for ARB processed alloy is rather high, suitable to be used as a material for bone substitute. Hardness of the ARB processed alloy is higher than that of the as-cast alloy, ensuring a better behaviour as a implant material. The tensile curve for the as-cast alloy shows an elastoplastic behaviour with a quite linear elastic behaviour and the tensile curve for the ARB processed alloy is quite similar with a strain-hardening elastoplastic body. Corrosion behaviour of the studied alloy revealed the improvement of the main electrochemical parameters, as a result of the positive influence of ARB processing. Lower corrosion and ion release rates for the ARB processed alloy than for the as-cast alloy, due to the favourable effect of ARB thermo-mechanical processing were obtained.

Tribocorrosion behaviour of Al/Al2O3 MMC produced by ARB process

The present study investigated the tribocorrosion behaviour of aluminium/alumina composite produced by accumulative roll bonding process during various cycles of processing. Tribocorrosion tests were performed using a ball-on-plate tribometer, where the sliding contact was fully immersed in 1 wt-%NaCl solution. The sample served as a working electrode, whose open circuit potential was monitored before, during and after sliding. Electrochemical impedance spectroscopy was used to characterise the electrochemical behaviour of the surfaces before and after the sliding wear test. The influence of Al2O3 particle distribution in the aluminium matrix on open circuit potential and electrochemical impedance spectroscopy was evaluated. It was found that the dispersion of alumina particles in the aluminium matrix strongly affected the measured corrosion characteristics. In addition, the results showed that non-uniformity of type and agglomeration of the particles in the aluminium matrix are related to serious material loss in the tribocorrosion process. The composite with homogeneous distribution of alumina displayed the highest tribocorrosion resistance.

Mechanical properties of precipitation strengthening Cu-base alloys highly deformed by ARB process

The enhancement of strength of Cu-1.2wt%Ni-0.2wt%Be-0.1wt%Zr and Cu-1.4wt%Ni-0.25wt%P-0.1wt%Zr alloys has been tried by the combination of ARB process by 5 cycles and aging treatment at 350 to 450°C. The grain sizes of the alloys, severely deformed by 5-cycle ARB process, were refined down to about 0.4μm. The Cu-Ni-Be-Zr alloy, ARB-processed and peak-aged at 375°C, exhibited a tensile strength σu of 810MPa, an elongation ɛt of 9% up to failure and an electrical conductivity σ of 62%IACS. The Cu-Ni-P-Zr alloy, initially aged at 450°C, then ARB-processed and peak-aged at 400°C, had the values of σu=780MPa, ɛt =6% and σ56%IACS.

Microstructure and mechanical properties of the accumulative roll bonded (ARBed) pure magnesium sheet

The pure Mg sheets were processed by ARB at 400 °C and 300 °C up to 8 cycles and 4 cycles, respectively. The microstructure was refined during the first cycle and only homogenized during the following ARB process due to the high deformation temperature, intermediate reheating and air-cooling. The ARB process did not show an obvious effect on the tensile properties of the as-ARBed pure Mg sheet due to the stable grain size and dominant basal plane texture during ARB. Further deformation should be introduced to improve the bonding quality of the as-ARBed sheet.

Tailoring Materials Properties by Accumulative Roll Bonding

AbstractAccumulative roll bonding (ARB) as a method of severe plastic deformation (SPD) is an interesting established process to produce ultrafine‐grained (UFG) sheet materials with high potential for light weight constructions. The ARB process offers a high flexibility for tailored material design. Al2O3 particles, carbon fibers and titanium foils are used as reinforcement of aluminum sheets introduced during accumulative roll bonding. Furthermore multicomponent materials are produced by cladding of different aluminum alloys. These sandwich‐like structures allow to combine desired properties of the materials involved. Post‐ARB heat treatment offers another possibility for tailoring materials properties of graded structures as shown by formation of TiAl3 in Al/Ti laminates. The tailored materials are investigated by means of SEM, EDX, nanoindentation experiments and tensile testing.

High performance of mechanical and electrical properties of Cu-Cr-Zr alloy sheets produced by ARB process and additional thermo-mechanical treatment

The additional cold rolling and the aging process were applied to Cu-0.85Cr-0.07Zr alloy sheets processed by ARB, and mechanical properties and structural information were investigated for the purpose of further improvement of the mechanical properties and the electrical conductivity. From the results of the tensile test and the measurement of electrical conductivity, ARB/aged/CR was most appropriate processing in order to achieve technical advantages. The high tensile strength of 745 MPa and the high electrical conductivity of 68 %IACS were obtained simultaneously. In addition, the improvement of incomplete boundaries generated during ARB processing was possible by thermo-mechanical treatment.

Microstructure and mechanical properties of accumulative roll bonded aluminium alloy AA5754

The aluminium alloy AA5754 is used for many technical applications. In this work, the accumulative roll bonding process is applied to this alloy in order to investigate the potential of an ultrafine-grained structure on the mechanical properties of this Al-Mg alloy. Sheets from AA5754 (AlMg3) were successfully processed by accumulative roll bonding in order to obtain an ultrafine-grained microstructure. The ARB process was performed at 230 °C or 250 °C up to 7 or 8 cycles respectively. Thus the grain size decreased from 10 μm (initial state) to approximately 80 nm (ultrafine-grained state, normal direction). The microstructural evolution and the mechanical properties have been investigated by means of scanning electron microscopy, hardness measurements and tensile testing. After one ARB cycle the samples showed an increase in hardness by a factor of almost 2 in comparison to the as-received material. Further processing causes a linear increase of hardness with each additional cycle. Yield strength and tensile strength of the roll bonded specimens are highly increased in comparison to the as-received samples whereas the ductility declined. A considerable increase in ductility is obtained by heat treatment of the ARB specimens at 250 °C, but on the expense of a moderate decreased strength. The deformation behaviour is also influenced by the ultrafine-grained structure. The occurrence of the Portevin-Le Chatelier effect is manifested by serrated stress-strain curves. The amplitude of serrations increases with increasing number of ARB cycles but can be reduced by the appliance of a higher strain rate. Lüders strain only occurs at the as-received, i.e. not strained, samples.

Nanostructure Formation during Deep Wire-Drawing of Copper

It was confirmed in the present study that deep drawing process in multi passes to produce fine wires of copper alloys can act as a kind of severe plastic deformation process. High purity copper was deeply wire-drawn up to an equivalent strain of 6.9, and microstructure evolution and change in mechanical properties were investigated. It was confirmed that deep wire-drawing process produced nanostructures composed of fiber-shaped ultrafine grains with a diameter of about 300 nm. The copper wires having nanostructures showed tensile strength of 480MPa, which was two times higher than that of the starting material. The microstructures and mechanical properties of the deep drawn copper wire were almost equivalent with those of the copper sheets severely deformed by ARB process, though there were some minor differences between two processes.

Manufacturing of high-strength aluminum/alumina composite by accumulative roll bonding

The ARB process used as a technique in this study provides an effective alternative method for manufacturing high-strength aluminum/alumina composites. The microstructural evolution and mechanical properties of the aluminum/15 vol.% alumina composite are reported. The composite shows an excellent alumina particle distribution in the matrix. It is found that by increasing the number of ARB cycles, not only does elongation increase in the composites produced but also the tensile strength of the Al/15 vol.% Al 2O 3 composite improves by 4 times compared to that of the annealed aluminum used as the original raw material. Fracture surfaces after tensile tests are observed by scanning electron microscopy (SEM) to investigate the failure mode. Observations reveal that the failure mode in both ARB-processed composites and monolithic aluminum is of the shear ductile rupture type.

Ultra Grain Refinement in a Plain Carbon Steel by Means of Warm Torsion Testing

Ultra grain refinement of a plain carbon SAE-AISI 1010 steel has been obtained by means of warm torsion testing. Tests were conducted at 500°C, constant strain rate of 0.1 s -1 and total equivalent strain of 0.8, 1.6, 4.0 and 5.6. The average ferritic grain size obtained was smaller than 0.5μm. The steel microstructure consisted of elongated ferrite grains and fragmented and spheroidized cementite particles, similar to the microstructures found in carbon steel severely plastic deformed, like in the ARB and ECAP processes. The average ferritic grain size is reasonably predicted by the Hall--Petch equation. The mechanisms by which ultra grain refinement has been achieved here has been attributed to dynamic recovery and continuous dynamic recrystallization of the ferrite during warm plastic deformation. Warm torsion testing proved to be a suitable tool to study grain refining mechanism through severe plastic deformation.