Fabrication of Al/Al2O3/TiC hybrid composite by anodizing and accumulative roll bonding processes and investigation of its microstructure and mechanical properties (original) (raw)
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Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011
Some important problems associated with cast metal matrix composites (MMCs) include non-uniformity of the reinforcement particles, high porosity content, and weak bonding between reinforcement and matrix, which collectively result in low mechanical properties. Accumulative roll bonding (ARB) process was used in this study as a very effective method for refinement of microstructure and improvement of mechanical properties of the cast Al/10 vol.% Al2O3 composite. The average particle size of the Al2O3 was 3 μm. The results revealed that the microstructure of the composite after eleven cycles of the ARB had an excellent distribution of alumina particles in the aluminum matrix without any noticeable porosity. The results also indicated that the tensile strength and elongation of the composites increased as the number of ARB cycles increased. After eleven ARB cycles tensile strength and elongation values reached 158.1 MPa and 7.8%, which were 2.54 and 2.36 times greater than those of the as-cast MMC, respectively.▶ Increasing the number of ARB cycles greatly improved the uniformity of Al2O3 particles. ▶ When the strain increased during rolling processes, porosity decreased. ▶ The strength of the composites improved when the number of ARB cycles increased. ▶ By increasing the number of ARB cycles, the elongation value improved.
Materials Science and Technology, 2019
Anodising, continual annealing and roll-bonding (CAR) processes were employed to fabricate aluminium/alumina/titanium composites with different amounts of alumina. After each rolling cycle, annealing treatment was performed at 300°C for 1 h. After six cycles of CAR process, the Al/0.22 vol.-% Al 2 O 3 /13vol.-%Ti composite showed uniform alumina and titanium particles distribution. The tensile strength of the composites first decreased after the first cycle, then increased up to 200 MPa after the sixth cycle. Conversely, by increasing the alumina content (Al/0.43vol.-%Al 2 O 3 /13vol.-%Ti composite), microhardness and tensile strength immediately increased. SEM micrographs demonstrated that by increasing the number of cycles, the dimples density increased from 0.007 to 0.028 µm −2 for the first and the last cycles, respectively.
Hybrid composites produced by anodizing and accumulative roll bonding (ARB) processes
Ceramics International, 2014
In this study, microstructure and mechanical properties of Al/1.6 vol% Al 2 O 3 /1.5 vol% B 4 C hybrid composite produced by anodizing and accumulative roll bonding (ARB) processes were investigated. Microstructural observations and fractography were performed by scanning electron microscopy (SEM). Also, the mechanical properties were investigated by tensile and microhardness tests. It was found that with increasing the number of ARB cycles, a better distribution of Al 2 O 3 and B 4 C particles was obtained in the aluminum matrix. The hybrid composite after the tenth cycle demonstrated a uniform distribution and a strong bonding between the particles and the matrix without any porosity. Furthermore, ARB-processed monolithic and also, the hybrid composite showed much higher tensile strength than the annealed aluminum sample. In addition, elongation of ARB-processed monolithic and also, the hybrid composite was decreased in the first step and then increased as a result of increasing the number of cycles. Moreover, the ARB-processed monolithic and the hybrid composite exhibited higher hardness than the annealed aluminum. Finally, it was realized that the monolithic and hybrid composite samples had a shear ductile fracture, dimples and shear zones. However, the number of sources in the void nucleation of the composite was more than that of the monolithic sample.
Manufacturing of high-strength aluminum/alumina composite by accumulative roll bonding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010
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 2 O 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.
Investigation of nanostructured Al/Al 2O 3 composite produced by accumulative roll bonding process
Materials and Design, 2012
In this study, the accumulative roll bonding (ARB) process was used for manufacturing nanostructured aluminum/15 vol.% alumina composites. Microstructural characterization by transmission electron microscopy (TEM) identified the severe shear deformation, however, the grain growth was restrained by particles of oxide film and recrystallization produced the nanograins with an average size <100 nm after the 13th cycle of composite strip. The findings also indicated that the presence of large particles and deformation structure in the vicinity of the particles made the particle stimulated nucleation (PSN) of recrystallization possible. The Williamson-Hall method was used to calculate the grain size from the X-ray diffraction (XRD) patterns, which were 150 nm for pure aluminum and 63 nm for aluminum/ alumina composite after 13 cycles of the ARB process. The findings also revealed that after the first cycle, hardness rapidly increased, then dwindled, and finally reached saturation as the number of ARB cycles increased.
Ceramics International, 2014
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.
Application of accumulative roll bonding and anodizing process to produce Al–Cu–Al2O3 composite
Materials & Design, 2015
In the present investigation, production of Al-Cu-Al 2 O 3 composite by means of Accumulative Roll Bonding (ARB) coupled with the anodizing process was studied. For this purpose, the alumina was grown on Al sheets by electrolyte technique and then the coated Al was laid between two Cu sheets followed by roll bonding to a specific reduction. This process was repeated up to seven times in order to achieve a bulk composite. The microstructure was characterized by SEM and optical microscopy while the mechanical properties were measured by microhardness, triple point bending and tensile testing. Microstructural evolution of the produced composite revealed that alumina was fractured in the primary sandwich and distributed non-uniformly throughout the composite. However, the alumina distribution was improved as the ARB cycles proceeded. It was also found that the tensile strength was improved up to the third cycle, after which it was decreased for the fourth and fifth cycles and again, it was increased for the last cycles. The bend strength showed the same trend as the tensile strength, while the elongation represented weak values for almost all cycles. Moreover, it was observed that as strain was increased (more ARB cycles), the microhardness for both Al and Cu layers was increased by two different trends. Additionally, failure analysis revealed that the mode of fracture was governed by two mechanisms: micro crack initiation between the metallic layers and formation of micro voids mainly around the alumina particles followed by their coalescence.
Teknika: Jurnal Sains dan Teknologi
Metalworking technology is currently developing rapidly, especially the processing of metal composite materials. The metalworking process in which ultra-large plastic strains are introduced into the device to create ultrafine grained (UFG) metal is a new method for producing high-strength metals. This method is called accumulative roll bonding (ARB). The ideal operating temperature used in the ARB process is the use of dynamic recrystallization temperatures. Roll compression in ARB affects the microstructure and mechanical properties of the composite material, where rolling compression can produce the application of simple forces sequentially evenly on the compressed workpiece. With the addition of Al2O3 and B4C reinforcement in the ARB process, it is expected that the mechanical properties will increase significantly. Composite AA1070 or Al2O3 produces an average hardness: 43.36 BHN, using B4C reinforcement increased 53.50 BHN with AA17075 with Al2O3 reinforcement the hardness was 87.20, with B4C increased significantly by 105.2 BHN. This study compares Al2O3 and B4C as reinforcement on an application in metal matrix composites (MMC). Characteristics compared and comparison of types of AA1070 or AA7075 matrix in their suitability between the use of matrix and reinforcement processed by ARB.
Application of anodizing and CAR processes for manufacturing Al/Al 2O 3 composite
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010
In this study, an anodizing process with different conditions was used to grow four different thicknesses of alumina on the surface of aluminum strips. Then, a continual annealing and roll-bonding (CAR) process was done to produce an aluminum matrix composite dispersed with four different volume fractions of alumina particles. The results demonstrate that when the number of cycles was increased, the distribution of alumina particles in the aluminum matrix improved, the particles became finer, and the tensile strength of the composites increased. The microstructure of the fabricated composites after 8 CAR cycles also showed an excellent distribution of alumina particles in the matrix. Moreover, it was observed that increasing alumina quantities through longer anodizing times enhanced the tensile strength of the composite to become 1.65 times higher than that of the monolithic aluminum produced by the same method, while negligible reductions were observed in the elongation value. Fracture surfaces after tensile tests were observed by scanning electron microscopy (SEM) to investigate the failure mode. Observations reveal that the failure mode in both CAR-processed composites and monolithic aluminum was the typical ductile fracture showing deep equiaxed dimples.
A Low Cost Method for Manufacturing of Aluminum/Alumina Composite by Anodizing and CRB Process
General Paper Selections, 2011
In this work, Al/Al 2 O 3 composite strips are manufactured by a low cost method consist cold roll bonding (CRB) process of anodized aluminum strips. This technique has the flexibility to control the volume fraction of metal matrix composites (MMCs) by varying the oxide layer thickness on the anodized aluminum strip. Meanwhile pre-and post-rolling annealing treatment was performed on some produced MMCs. Microstructure, hardness, tensile strength, and elongation of composite strips are investigated as a function of alumina quantity and the applied production method. It is found that higher quantities of alumina improve hardness and tensile strength, while the elongation value decreases negligibly. Furthermore, pre-rolling annealing was found to be as the best method for producing this composite via the anodizing and CRB processes. Finally, it was found that both monolithic aluminum and aluminum/alumina composite exhibited a ductile fracture, having dimples and shear zones.