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Abstract We created AA2024–AA1050 and AA2024–AA1050/0.005 vol.% Al2O3 nanocomposites by six accumulative roll bonding (ARB) process cycles. We used AA2024 and AA1050 sheets with a thickness of 0.7 mm and plate-shaped alumina nanoparticles to create a composite. The two AA1050 and one AA2024 sheets (among the two AA1050 sheets) were ARB-ed up to six cycles with and without adding alumina nanoparticles. Also, a sample of the AA1050 without composite making was ARB-ed up to six cycles. We aged some composites after the ARB process in the furnace at 110, 150, and 190 °C. This project performed SEM, TEM, and EDS-MAP analyses, tensile strength, microhardness, and Pin-on-Disc tests to study the ARB-ed sheets. The results of the tensile tests showed that the tensile strength of AA2024–AA1050 created by the six cycles ARB process was two times more than primary AA1050. Also, the wear resistance of this composite was 74% more than six cycles ARB-ed the AA1050. Using 0.005 vol.% alumina nanoparticles in AA2024–AA1050 composite improved its wear resistance by 30%. In the following, the aging process caused an improvement in tensile strength and total elongation of AA2024–AA1050/Al2O3 nanocomposites.

We created AA2024–AA1050 and AA2024–AA1050/0.005 vol.% Al2O3 nanocomposites by six accumulative roll bonding (ARB) process cycles. We used AA2024 and AA1050 sheets with a thickness of 0.7 mm and plate-shaped alumina nanoparticles to create a composite. The two AA1050 and one AA2024 sheets (among the two AA1050 sheets) were ARB-ed up to six cycles with and without adding alumina nanoparticles. Also, a sample of the AA1050 without composite making was ARB-ed up to six cycles. We aged some composites after the ARB process in the furnace at 110, 150, and 190 °C. This project performed SEM, TEM, and EDS-MAP analyses, tensile strength, microhardness, and Pin-on-Disc tests to study the ARB-ed sheets. The results of the tensile tests showed that the tensile strength of AA2024–AA1050 created by the six cycles ARB process was two times more than primary AA1050. Also, the wear resistance of this composite was 74% more than six cycles ARB-ed the AA1050. Using 0.005 vol.% alumina nanoparticles in AA2024–AA1050 composite improved its wear resistance by 30%. In the following, the aging process caused an improvement in tensile strength and total elongation of AA2024–AA1050/Al2O3 nanocomposites. [ABSTRACT FROM AUTHOR]

This study investigated the microstructure, texture, and mechanical properties of 1050 aluminum alloy sheets that underwent the accumulative roll bonding (ARB) method. The ARB proceeded up to eight passes in three ways: conventional process, preheat between rolling passes (preheating) or anneal between rolling passes (annealing). Heat treatment was done between the ARB passes for 5 min at 150 °C. The mean grain width of the 1050 Al sheet that was 11 μm before ARB, decreased to 295.73 nm, 317.33 nm, or 339.23 nm after six ARB passes in the conventional process, annealed or preheated conditions, respectively. Concurrent heat treatments cause a decrease in the strength of the texture components of Al sheets that were elaborated by the ARB method. Even though conventional and annealed processes successfully enhanced the microhardness by ∼80% and tripled the tensile strength, these improvements were weaker in the preheated condition than the other conditions due to dynamic recovery.

In the present work, aluminum‐3% brass composite sheets are produced by accumulative roll bonding (ARB) process up to nine passes at ambient temperature. Evolution of rolling texture is studied by texture measurement using X‐ray diffraction method. The results show that ARB process leads to the formation of copper ({112} <111>) and Dillamore ({4 4 11} <11 11 8>) as the major texture components. The intensity of copper and Dillamore components enhances to values as high as 19 times that of random with increasing number of passes to 9. It is observed that the 5th pass is a transition in development of the texture components, after which the intensities undergo a drop. The textures are comparable to ARB process of high purity aluminum, indicating that the addition of 3% brass particles do not cause any significant change in the deformation behavior. Electron backscatter diffraction (EBSD) technique is used to examine the microstructure; the results reveal formation of ultrafine grains (UFG), starting in the 3rd pass and covers the entire structure after the 5th pass. The major mechanisms involved are identified as rotation of the sub‐grains, as well as grain boundary migration. [ABSTRACT FROM AUTHOR]

In this study, a kind of Al-TiB2/TiC in situ composite was successfully prepared using the melt reaction method and the accumulative roll-bonding (ARB) technique. The microstructure evolution of the composites with different deformation treatments was characterized using field emission scanning electron microscopy (FESEM) and a transmission electron microscope (TEM). The mechanical properties of the Al-TiB2/TiC in situ composite were also studied with tensile and microhardness tests. It was found that the distribution of reinforcement particles becomes more homogenous with an increasing ARB cycle. Meanwhile, the mechanical properties showed great improvement during the ARB process. The ultimate tensile strength (UTS) and microhardness of the composites were increased to 173.1 MPa and 63.3 Hv after two ARB cycles, respectively. Furthermore, the strengthening mechanism of the composite was analyzed based on its fracture morphologies. [ABSTRACT FROM AUTHOR]

Accumulative roll bonding (ARB) has been used as a severe plastic deformation process for the industrial production of ultra-fine grained (UFG) and nano-crystalline sheets with excellent mechanical properties. In the present study, the effect of the ARB process on the corrosion behavior of UFG and nano-crystalline 1050 aluminum alloy in a buffer borate solution (pH 5.5) has been investigated. The result of microhardness tests revealed that microhardness values increase with an increasing number of ARB cycles. A sharp increase in microhardness is seen after three ARB cycles, whereas moderate additional increases are observed afterward for up to nine cycles. Also, the XRD results showed that the mean crystallite size decreased to about 91 nm after nine cycles. The potentiodynamic plots show that as a result of ARB, the corrosion behavior of the UFG and nano-crystalline specimens improves, compared to the annealed 1050 aluminum alloy. Moreover, electrochemical impedance spectroscopy measurements showed that the polarization resistance increases with an increasing number of ARB cycles. [ABSTRACT FROM AUTHOR]

Microstructural changes, such as the density of grain boundary (GB) and dislocation density, due to isochronal annealing in severely plastic-deformed commercial purity aluminium up to 523 K was evaluated using electrical resistivity measurements and scanning transmission electron microscopy. Eventually, the GB density decreases from about 7.2  ×  106to about 2  ×  106 m−1, whilst the dislocation density decreases from an initial value of around 1.3  ×  1014 m−2down to around 4  ×  1013 m−2. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Al/Al2O3/SiC hybrid composite was fabricated by anodizing and ARB processes. [•] With no. of ARB cycles, the uniformity of particles in the Al matrix improved. [•] With no. of ARB cycles, the bonding quality between particles and matrix improved. [•] The UTS of Al/1.6vol.% Al2O3/1vol.% SiC was 3.1 times higher than annealed Al. [•] Increasing the amount of the SiC up to 2vol.% in matrix decreased UTS and El%. [ABSTRACT FROM AUTHOR]

Highlights: [•] Because of the ARB process, the general corrosion resistance decreases. [•] With increasing the number of ARB cycle, the corrosion resistance slightly increases. [•] The corrosion resistance of the nanocomposites increases in the lower cycles. [Copyright &y& Elsevier]

Abstract: Dislocation density within ultrafine grains in severely deformed aluminium was evaluated by the scanning transmission electron microscopy. The values were around 1014 m−2 in commercial pure aluminium samples with equivalent strain up to 10. The obtained dislocation densities values correspond to strength between 55MPa and 70MPa according to the Bailey–Hirsch relationship. [Copyright &y& Elsevier]

Product miniaturisation and functional integration are currently global trends to save weight, space, materials and costs. This leads to an increasing demand for metallic micro components. Thus, the development of appropriate production technologies is in the focus of current research activities. Due to its efficiency, accuracy and short cycle times, microforming at room temperature offers the potential to meet the steadily increasing demand. During microforming, size effects occur which negatively affect the part quality, process stability, tool life and handling. Within this contribution, a multi-stage bulk microforming process from sheet metal is investigated for the materials Cu-OFE and AA6014 with regard to the basic feasibility and the occurrence of size effects. The results reveal that the process chain is basically suitable to produce metallic micro parts with a high repeatability. Size effects are identified during the process. Since several studies postulate that size effects can be minimised by scaling down the metallic grain structure, the grain size of the aluminium material AA6014-W is scaled down to less than one micrometre by using an accumulative roll bonding process (ARB). Subsequently, the effects of the ultrafine grain (UFG) structure on the forming process are analysed. It could be shown that a strengthened material state increases the material utilization. Furthermore, too soft materials can cause damage on the part during ejection. The occurring size effects cannot be eliminated by reducing the grain size. [ABSTRACT FROM AUTHOR]

Abstract: High-purity aluminum (99.99% purity) deformed by accumulative roll bonding to an equivalent strain of 4.8 has been characterized by transmission electron microscopy and electron backscatter diffraction techniques in the deformed state and after various annealing treatments. These two techniques are compared and discussed. The majority of the structure in the as-deformed state is composed of equiaxed crystallites surrounded mostly by high-angle boundaries with misorientation angle above 15°. However, regions that contain a high concentration of low-angle boundaries with misorientation angle below 15° in a lamellar structure elongated along the rolling direction have also been observed. The microstructure is correlated with the local texture as the equiaxed structure contains a mixture of texture components whereas the lamellar structure has orientations corresponding to rolling or shear texture components. Annealing of deformed specimens causes structural coarsening without removing the regions with a high concentration of low-angle boundaries. Heat treatment for a short period of time (0.5h) leads to the start of recrystallization at 200°C, whereas a heat treatment at 175°C for an extended period (6h) allows heat treatments to be carried out at temperatures above 200°C without initiation of recrystallization. The two-step process is a promising route for producing almost uniform equiaxed structures by annealing of samples that have been deformed to large strains. [Copyright &y& Elsevier]