Accumulative Roll Bonding Process Research Articles

Enhanced mechanical properties of lamellar Cu/Al composites processed via high-temperature accumulative roll bonding

Abstract Cu/Al multilayers were produced by high-temperature accumulative roll bonding (ARB) methods up to three passes. To achieve a high bonding strength, prior to ARB processing, the Cu and Al sheets were heated to 350, 400, 450 and 500 °C, respectively. The mechanical properties were evaluated by tensile tests. The microstructure was examined by optical microscopy and scanning electron microscopy equipped with energy dispersive spectrometry. The ultimate tensile stress, the grain size and the thickness of diffusion layer of lamellar composites increase with rolling temperature. When the rolling temperature is 400 °C, the laminates show the highest ductility, but the yield stress is the lowest. As the rolling temperature further increases, both the yield stress and the ultimate tensile stress increase and the ductility decreases slightly. The mechanical properties of lamellar composites processed by low and high temperature ARB are determined by grain size and the thickness of diffusion layer, respectively.

A substantial improvement of tensile properties through microstructure engineering in a high Ni-0.2C TRIP steel under severe plastic deformation

In the present paper, microstructural evolution and mechanical properties changes of an ultrafine-grains (UFGs) Fe-24Ni-0.2C steel processed via accumulative roll bonding (ARB) is investigated. Characterization of microstructure with Electron Backscatter Diffraction (EBSD) technique revealed that a substantial grain refinement happened after 6-cycle ARB process. As well, elongated UFGs austenite with mean grain size smaller than 200 nm was obtained in such a condition. Furthermore, phase analysis map acquired from EBSD technique revealed that the microstructure of the starting sheet contained martensite (>30%) which transformed to austenite after 6 cycles of ARB process. Such a phenomenon indicated that, through grain refinement, austenite stabilization is attainable with the ARB process. It was also found that yield/tensile strengths, as well as toughness of the ARB processed specimens are enhanced, particularly when the ARB cycle is increased. Finally, it was established that deformation-induced martensite transformation provides extra strain hardening capability ensuing a substantial enhancement of uniform elongation and toughness in the UFGs metastable austenitic steel. This UFGs steel showed considerable uniform elongation and ultrahigh strength at 6-cylce ARB process.

Evolution of Microstructure, Mechanical Properties, and Thermal Conductivity of an Al-Li-Cu-Mg-Zr Alloy Processed by Accumulative Roll Bonding (ARB)

Al-Li-Cu-Mg-Zr alloy was processed by accumulative roll bonding (ARB). The microstructure, mechanical properties, and thermal conductivity were investigated. With increasing number of ARB cycles, the microstructure was refined and the processed strips exhibited metallurgical bonding. During ARB processing, the tensile strength was enhanced while the elongation remained in a stable range. The sample after two cycles showed the best comprehensive combination of strain hardening, grain refinement, and high bonding quality, resulting in tensile strength, elongation, bending strength, and thermal conductivity of 322.34 MPa, 17.84%, 528.67 MPa, and 202.26 W/m K, respectively. Further increasing the rolling cycles weakened the investigated properties of the studied alloy. With increasing number of ARB cycles, the tensile fracture morphology revealed that the average dimple size steadily decreased, causing a change in the fracture type from ductile to mixed ductile–shear. The obtained ARB-processed samples resisted greater bending deformation with no damage or interfacial delamination.

Microstructure and reaction properties of Ni/Al micro-nano composites produced by accumulative roll bonding process

Ni/Al micro-nano composites have received much attention due to their attractive properties, especially high energy density and stable strength. This presented work aims to propose a simple and cost-effective method for preparing Ni/Al micro-nano composites that have good reaction performance and specific tensile strength and explore their microstructure evolution and reaction property. The Ni/Al micro-nano composites were fabricated by the accumulative roll bonding (ARB) using pure nickel and Al foils. As the ARB cycles gradually increased, the foils get thinner and transition from a straight to a wavy shape, such as necking and fracture of Ni. The interface contact area was increased by the more uniform and slender nickel-aluminum layer distribution during ARB process. Furthermore, the energy density during the exothermic reactions of the Ni/Al composites firstly increased and then decreased with the decrease of interlayer thickness. The energy density of the Ni/Al micro-nano composite after 13th ARB cycles was 1362.5 J g−1, which was about 92% of the theoretical value. The initial reaction temperature of the composites decreased with the increase of rolling cycles. Al3Ni, Al3Ni2 and AlNi intermetallic phases were generated in exothermic reactions. Besides, the activation energies of Ni/Al composites calculated by Kissinger and Ozawa method were 52.91 and 59.68 kJ mol−1, respectively. After the 13th rolling cycle, the tensile strength was 368.70 MPa while the elongation was 4.2%.

High-strength and ductility bimodal-grained Al–Li/Al–Li–Zr composite produced by accumulative roll bonding

Microstructure evolution and mechanical behavior of bimodal-grained Al–Li/Al–Li–Zr laminated composite by accumulative roll bonding (ARB) were investigated. As-rolled Al–Li and as-annealed Al–Li–Zr sheets were bonded up to 5 cycles at room temperature. In the 5-cycle ARB processed Al–Li/Al–Li–Zr layered composite, straight and continuous bonding interfaces were formed between the soft Al–Li layers and hard Al–Li–Zr layers. No macro shear bands were observed, indicating that a uniform deformation occurred between different materials in the ARB process. A bimodal grain distribution of the micro-size elongated grains (1.3 μm) in the Al–Li–Zr layers due to the precipitation of Al3(Zr,Li) and the nanoscale ultra-fine grains (320.0 nm) in the Al–Li layers due to the recrystallization process was found. Microhardness in the Al–Li and Al–Li–Zr layers and tensile strength of the composite increased with the number of ARB cycles. However, the ductility first decreased at the 1-cycle ARB process then increased at 2–5 cycles ARB process. The best mechanical properties (UTS = 388 MPa and EL = 12.7%) were obtained in the 5-cycle ARB process. The high strength and ductility could be explained for the contributions from strain hardening, grain refinement, no macro shear bands and the formation of a bimodal grain size distribution.

Evaluation of mechanical and thermal properties of bilayer graphene reinforced aluminum matrix composite produced by hot accumulative roll bonding

Here in this literature, incorporation of graphene in commercially pure aluminum by hot accumulative roll bonding (ARB) is studied. Annealed Al sheets were hot ARB processed up to 6 passes by repetitive graphene coating, stacking, rolling and cutting process respectively. Another set of monolithic Al was also processed with similar processing parameters for comparative study. A good interface between graphene and aluminum was observed under transmission electron microscopy. Interlayer bonding and grain boundary structure were examined by scanning electron microscopy and electron backscattered diffraction mapping respectively. The fraction of high angle grain boundaries not only increases with respect to ARB passes but also with graphene incorporation. Raman mapping was also performed to understand the quality as well as the distribution of graphene. Tensile strength and hardness of processed composite were increased up to 25% and 20% respectively in comparison to monolithic Al which is attributed to graphene reinforcement effect. Thermal conductivity (TC) of annealed Al, 6pass monolithic Al, and 6pass graphene/Al composite was also measured. Due to ARB processing, TC of annealed Al was reduced by ∼17% but the addition of 0.1 wt % graphene was able to recover the reduced TC.

Using digital image correlation for characterizing the elastic and plastic parameters of ultrafine-grained Al 1050 strips fabricated via accumulative roll bonding process

In the present article, digital image correlation (DIC) system has been utilized to determine the elastic and plastic parameters of ultrafine grained (UFGed) Aluminum 1050 strips fabricated via accumulative roll bonding (ARB) procedure during the uniaxial tensile test. At first, elastic and plastic parameters such as elastic modulus, Poisson ratio, strength coefficient, strain hardening exponent, anisotropy coefficient and yield stress of ARBed specimens have been extracted in different ARB passes. ARB process is an exceptional process to fabricate ultrafine-grained and nanostructured sheet metals and composites. Using of UFGed materials in various industries requires accurate identification of their mechanical and physical properties. Elastic modulus and anisotropy are the most important mechanical parameter for structural design and forming process respectively. The ARB process has been done up to seven passes by the value of 50% thickness reduction during rolling in every ARB pass at the ambient temperature. Results exhibited which via rising the ARB passes, as expected the elastic parameters did not change much, but all of the plastic parameters and crystallite size changed. The values of the ultimate tensile strength (UTS) and yield stress (YS) increased sharply but strain hardening exponent and elongation at first pass decreased severely and then from third to the seventh pass increased continuously. Due to the gradient of applied shear components in the thickness direction during rolling, the anisotropy coefficient is one of the most important parameters for severe plastic deformation based on rolling. In this paper, for the first time anisotropy variations in the tensile test were continuously determined and the results of the DIC demonstrated that changing of the anisotropy in each pass were different and via raising the value of applied strained the amount of anisotropy coefficient reduced.

Microstructure and Mechanical Behavior of MnO2/Pb Nanocomposite

MnO2/Pb nanocomposite was produced by solid-state accumulative roll-bonding (ARB) technique. Composites with different amounts of MnO2 were synthesized with the highest probable ARB cycles. The mechanical properties of composites were studied by tensile, microhardness and shear punch tests. It was observed that yield stress, tensile stress and elongation were improved by increasing the ARB cycles. On the other hand, increasing the amount of MnO2 up to 0.5 wt.% improved the mechanical properties of the composites. Tensile tests results revealed that the maximum tensile strength could be achieved in the composite containing 0.5 wt.% MnO2 after 10 passes (up to 4.35 times higher than control sample, Pb-10 pass). In comparison with Pb-10 pass, the hardness of 0.5 wt.% MnO2/Pb nanocomposite was enhanced up to 7.5 times after 10 ARB passes. ARB process led to a proper distribution of MnO2 particles in Pb matrix with the mean size of less than 30 nm.

Al matrix composites reinforced by high volume fraction of TiAl3 fabricated through combined accumulative roll-bonding processes

Ultrafine-grained Al matrix composites reinforced by TiAl3 particles with volume fractions (Vp) up to ∼49% were fabricated from nano-sized Ti powders and pure Al sheets via room-temperature accumulative roll-bonding (RT-ARB) combined with hot-ARB at high temperatures. The RT-ARB was first applied to disperse the Ti nanopowders uniformly in Al matrix. In situ formation of TiAl3 particles via reaction of Ti and Al was induced during subsequent hot-ARB process at 600 °C. It was found that further hot-ARB at 700 °C can enhance the volume fraction and the dispersion of TiAl3 remarkably. The microhardness and tensile strength of the final composites are significantly improved as compared to those of pure Al and increase with increasing volume fraction of TiAl3, reaching a maximum of ∼180 HV and ∼455 MPa for Vp = 49%, respectively. The high strength of the TiAl3/Al composites can be attributed to the superimposition of strengthening mechanisms which are dominant at high Vp.

Influence of rolling temperature on microstructural evolution and mechanical behavior of AZ31 alloy with accumulative roll bonding

The effect of rolling temperature on AZ31 alloy with accumulative roll bonding (ARB) had been investigated. The results showed that dynamic recrystallization occurs and forming shear bands in the direction of shear stress, exhibit the shape that width decreases from the surface to the inside when ARB at 450 °C. Strength was increased result by strain hardening after ARB process, with compromise of elongation was attributable to the internal crack. Microhardness was enhanced after ARB, while decreasing with the increase rolling temperature. Because of the formation of shear band, microhardness of outer plate was lower than inner plate. Interface bonding strength was increased by improving ARB temperature. Interface bonding is a process in which dynamic recrystallization occurs on both sides of the interface, fine recrystallized grains constantly swallowed and replace the original grains until the interface is annihilated. Crack initiation in shear band and extends along the shear band.

Production of a high strength Al/(TiAl3+Al2O3) composite from an Al-TiO2 system by accumulative roll-bonding and spark plasma sintering

A bulk in-situ Al/(TiAl3+Al2O3) composite was fabricated by accumulative roll-bonding (ARB) and spark plasma sintering (SPS) from pure Al sheets and TiO2 nanoparticles. The microstructure and mechanical properties of the composite were investigated. A uniform dispersion of TiO2 nanoparticles in Al matrix was first achieved by ARB processing in the primary Al/TiO2 composites. Subsequent SPS resulted in the formation of hierarchical TiAl3 (∼60 nm) and Al2O3 (∼750 nm) particles that were distributed uniformly in the ultrafine-grained Al matrix. Microhardness and strength (at ambient and high temperatures) of the final composite were substantially enhanced compared with those of pure Al and the primary Al/TiO2 composite, reaching ∼198.6 HV, ∼628.8 MPa at room temperature and ∼384.2 MPa at 300 °C, respectively. The high strength of the Al/(TiAl3+Al2O3) composite was attributed to a superimposition of different strengthening mechanisms.

A crystal plasticity FEM study of through-thickness deformation and texture in a {112} aluminium single crystal during accumulative roll-bonding

In this study, a crystal plasticity finite element method (CPFEM) model was used to study the deformation behaviour in an aluminium single crystal (1 1 2)[1 1 -1] processed by accumulative roll-bonding (ARB) up to 9 cycles. The simulation followed the real ARB process based on the developed finite element model. The predicted through-thickness texture matches well with the experimental observations. The deformation behaviours, in terms of crystal rotation, shear strain and slip system activation, in the first and second cycles (conventional rolling) were unidirectional, but the deformation was altered after ARB was applied from the third cycle onwards. Such alteration was found to be caused by the thickness position change and deformation discontinuity at interfaces, which were investigated in detail. The role that interfaces play became dominant over thickness position change as increasing ARB cycles.

Laminated TRIP/TWIP Steel Composites Produced by Roll Bonding

In order to investigate the roll bonding of high-alloy transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP) steel, roll-bonded sheets of the TRIP and TWIP steel were manufactured starting from hot rolling, followed by brushing and cold rolling. Both, the microstructure and mechanical properties of the roll-bonded sheets were characterized by metallographic investigations, and tensile and T-peel tests. Preliminary results, such as an occurrence of an adhesive bonding between two TWIP steel sheets and between TRIP and TWIP steel sheet after a thickness reduction of approximately 50% were obtained. Moreover, the formation of deformation-induced martensite leads to outstanding mechanical properties of the roll-bonded composite sheet. An ultra-fine grained microstructure was observed in the bonding zone after only one roll-bonding process. The obtained promising results demonstrate the possibility of the development of an accumulative roll-bonding process for TRIP/TWIP steel composites.

Microstructure of accumulative roll bonded high purity aluminium laminates

Aluminium sheets of high purity were produced by accumulative roll bonding (ARB) at room temperature. The microstructure of the sheets up to 16 ARB cycles was analyzed by scanning electron microscopy. In all sheets discontinuous dynamic recrystallization occurred leading to coarse grains. In general, the grain size decreases with increasing number of applied ARB cycles, but remains much larger than the theoretical layer thickness after 6 or more ARB cycles. It is shown for the first time, how the interfaces introduced by ARB have a significant effect on the elongated grain shape by a combined experimental-numerical study: The resulting microstructure is qualitatively discussed with regard to defects introduced at the interfaces by the ARB process, while two-dimensional Potts model simulations yield very good qualitative agreements with the experiments and underpin the importance of the ARB interfaces as barriers for the motion of grain boundaries.

Manufacturing and Characterization of Multilayered 7000-Series Aluminum with Improved Corrosion Behavior Processed via Accumulative Roll Bonding

High-strength aluminum alloys are promising materials for automotive structural parts since they offer a great potential to reduce vehicle weight and greenhouse gas emissions. For this reason, 7000-series aluminum alloys recently became object of many investigations. However, one major drawback of these alloys is their poor corrosion behavior, which is a crucial aspect and currently limits its application in automotive industry. One approach to influence this factor, without changing the alloying system, is the accumulative roll bonding (ARB) process. Within this contribution, a multilayered material consisting of discrete layers of AA7075 and AA1050 will be manufactured via ARB. The influence of the ARB process on the resulting mechanical properties of the multilayered material will be evaluated applying tensile tests and it will be compared with the initial condition of both single layered materials. Furthermore, the effect of the combination of these two aluminum materials on the corrosion behavior will be investigated

Fine Texture Enhancement of Al-Mg-SC alloy by Using Cross Accumulative Roll Bonding Technique

Aluminum alloys were as a rule used to fabricate in a few car and aviation parts. Al-Mg-Sc combination sheets were prepared a couple of cycles of Cross accumulative roll bonding (CARB) & similarly of accumulative roll bonding (ARB). In these two procedures Micro-structural advance have been occurring. It was clearly observed microstructure depicted by checking electron microscopy (SEM). In the midst of these both the system, Al-Mg-Sc alloys was adequately made with no disfigurement. In the midst of CARB process, Reinforcement (Mg, SC) particles reliably scattered inside Al system differentiated and similarly examined Al-Mg-Sc alloys in ARB process. In these two procedures, to incorporating of minor Sc in Al-Mg was extended hardness and besides it credited to the fine surface development. TEM imaging demonstrates development of fine hastens shaped inside grid in CARB contrast and ARB amid heat treatment. The Al-Mg-Sc alloy hardness was evaluated with using a Vickers hardness analyzer.

Lead cathodes functionalized with magnetite particles with enhanced electrocatalytic activity for hydrogen evolution reaction in sulfuric acid solutions

The generation of molecular hydrogen through the electrochemical water splitting process has been extensively studied, due to the potential application of hydrogen to produce green energy with fuel cells. Researchers have been focused in the synthesis of electrocatalysts for the hydrogen evolution. The accumulative roll bonding (ARB) is a promising method which can process a large quantity of an electrode for industrial demand. In this research the ARB process is employed to synthesize lead base electrodes functionalized with magnetite particles (Fe3O4) to evaluate their electrocatalytic properties on the hydrogen evolution reaction (HER) in sulfuric acid solutions. SEM, EDS and FESEM techniques are used to characterize the functionalized lead cathodes. The effect of rolling passes, magnetite concentration, and suspended magnetite particles on the HER kinetics is studied using linear voltammetry, Tafel plots, and electrochemical impedance spectroscopy (EIS). The results revealed that lead cathodes functionalized with magnetite present great advantages over lead cathodes, such as: a decrease of 0.37 V in HER over-potential, an increase of 84.3 times in the exchange current density, a decrease in the charge transfer resistance of 98%. From a mechanistic viewpoint, HER is catalyzed by the presence of Fe2+ adsorbed on the lead cathode; ferrous ions are produced from the reductive dissolution of magnetite particles. Long-term electrolysis and multiple cyclic voltammetry tests (800 polarization cycles) revealed that the catalytic effect is maintained during 44 h of operation. According to the Tafel curves and EIS results, the Volmer reaction is the rate determining step of the HER on these functionalized cathodes.

Electrochemical performance of Pb[sbnd]Co composite anode during Zinc electrowinning

In this study, the electrochemical and anodic behaviors of CoPb anodes in electrowinning process were investigated. Accumulative roll bonding (ARB) method was applied to fabricate CoPb composites. The electrochemical properties of the produced anodes were investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry technique (CV), electrowinning tests, and scanning electron microscopy (SEM). The results indicated that ARB-process is an appropriate method to developed CoPb anodes. The produced anodes containing 0.5% of Cobalt particles as a second phase after 10 cycles of ARB process which is named Pb-0.5%Co-10pass samples showed 83.37% increase in current density compared to pure lead anode. The results of electrowinning tests revealed that Pb-0.5%Co-10pass samples had the best anodic performance with a significant lower corrosion rate, product and electrolyte contamination, slime formation, energy consumption and a higher Zn deposit as a product and energy conservation.

Accumulative Roll Bonding for Improvement mechanical properties of Aluminum based Composite

The Aluminum has special properties such as light weight, ductile and a lower melting point. It has very suitable for applied as composite material, with ceramic as reinforcement. Accumulative roll bonding (ARB) is part of technology of Severe Plastic Deformation (SPD) that has been developed of manufacturing process for metals, alloys and composites as well. It has a potential becoming an industrial process to produce composite and ultrafine-grained (UFG) metal sheets. In this research, the development of aluminum-based composites is made by SPD technology using the ARB method on aluminum plate sheets with boron carbide (B4C) as reinforcement, is expected to improve its mechanical properties along with the rules of microstructure analysis. To get of the UFG metallic materials where the mean grain size must be smaller than 1μm are expected can be exhibit excellent mechanical properties. The ARB process consists of multiple cycles of rolling, cutting, stacking and solid-state deformation bonding. Two plates were prepare for the ARB sample process, cleaning uses acetone liquid to prevent attachment of dust and dirt on the surface to be made in contact with other samples. Acetone and grinding to produce a rough surface to facilitate the surface binding process between samples, B4C powder is sprinkled between the centers of aluminum plate surface and stacked going together.

Study on Texture Evolution and Shear Behavior of an Al/Ni/Cu Composite

The microstructure, texture, and mechanical properties of the Al/Ni/Cu composite during various accumulative roll bonding (ARB) cycles were studied using optical microscopy, scanning electron microscopy, x-ray diffraction, shear punch test, and hardness test. In addition, ImageJ software and Rietveld software were used in order to study microstructure and dislocation density variations, respectively. It was found that Ni and Cu layers were fractured and distributed in the Al matrix due to differences in their mechanical properties. Fracture and distribution of Cu and Ni particles after cycle five led to the alteration of the composite structure from a layered to a particle-reinforced structure. ARB process leads to the formation of strong orientation along the β-fiber and also to pronounced copper and dillamore components in both Al and Cu phases. Furthermore, the shear yield stress and ultimate shear strength of the composite increased as the ARB process advanced; however, shear elongation presented a non-uniform variation. Investigation of the fracture surfaces revealed that the mechanical properties of the composite are affected not only by the strain hardening of the Cu layer, but also by the structural change in the composite during the initial ARB cycles. During the last stages of the process, however, changes in mechanical properties were mostly governed by reinforcement particles serving as strain concentration zones and the strain hardening of the Al matrix.