The strength of aluminum Al5083 laminated composite in accumulative roll bonding (ARB) is increased using Al2O3 nanoparticles. For this purpose, the ARB process was conducted at room temperature without lubricants in four consecutive passes. A thickness reduction of 50% in each pass was considered with no heat treatment between sequential passes. In each pass, Al2O3 nanoparticles were placed between the layers. Finally, the produced metal composite was evaluated for microstructural and mechanical properties using optical microscopy, and uniaxial tensile, microhardness, and peeling tests according to the relevant standards. The primary objective of this research was to enhance the tensile strength of the composite after work hardening by incorporating nanoparticles and annealing in the final cycle. The results showed that with an increase in accumulative roll bonding cycles, tensile strength and hardness increased, and this increase occurred more prominently in the initial cycles. Furthermore, the amount of elongation decreased at the end of the first pass and then increased until the end of the fourth pass. These changes in mechanical properties during the ARB process are due to the dominant mechanisms of work hardening and strain hardening in the initial cycles and the improvement in microstructure and refinement of grains in the final cycles of this process. The highest tensile strength and microhardness, which increased by 48.1% and 55.9%, respectively, compared to the initial sample were measured at the end of the fourth cycle. Additionally, comparing the heat-treated sample with Al2O3 nanoparticles to the base metal showed a 34.9% increase in strength and a 30.8% decrease in elongation.

Friction stir processing is a solid state process to modify microstructure and mechanical properties of sheet metals and as-cast materials. In this process stirring action of the tool causes the material to intense plastic deformation that yields a dynamical recrystallization. In this study the effect of FSP and process parameters on hardness, and microstructure of Al5083 has been investigated. Also by using of FSP, composite layer of TiO2/Al5083 has been produced. Results show that, FSP leads to finer and homogenized grain structure, as well as increased hardness, strength, toughness, and elongation of material. The composites produced by FSP have uniformly distribution of TiO2 particles between the grains of base metal.

In the present study, Al5083- Al2O3 nanocomposite was successfully prepared by friction stir processing (FSP) with the rotational speed of 710 rpm and travel speed of 14 mm/min. In order to improve the distribution of Al2O3 particles, a net of holes was designed on the surface of Al5083 sheet. The samples were characterized by optical (OM) and scanning electron microscopy (SEM), and microhardness, tensile, and wear tests. The results showed that FSP is an effective process to fabricate Al5083- Al2O3 surface nanocomposite. Microstructural observation demonstrated fine and equiaxed grains and homogenous distribution of Al2O3 nanoparticles in the stir zone (SZ). The presence of Al2O3 nanoparticles leads to a decrease in the grain size from 45 to 7 mm and an increase in microhardness from 80 to 140 Hv and tensile strength from 280 to 335 MPa. Wear test results showed an improvement in wear resistance due to its higher hardness. Also, the wear mechanism in all samples was abrasive.

In the present study, bulk refined-structured Al 5083 alloy with high mechanical properties was successfully fabricated by hot consolidation process of nanostructured melt- spun flakes. The influence of cooling rate and pressing conditions on the microstructure and mechanical properties of the alloy were investigated using X-ray diffractometer (XRD), optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), microhardness, and compression tests. Rapid solidification combined with the hot consolidation at T=753 K (480 °C) and P= 800 MPa for 20 min produced a bulk sample with the desirable bonding, good microhardness (184.2±12.4 HV), and high strength (273±8 MPa) combined with 7 pct. fracture strain. These amounts are 78.6±5.1 HV, 148 ±9 MPa and about 5 pct. for the as-cast sample. Microstructural refinement during the controlled consolidation of nanostructure rapidly- solidified flakes contributes to such high mechanical properties of the bulk sample.

This paper deals with experimental and numerical studies of fracture behavior of Al. 5083-H321 alloy, under uniaxial and biaxial tensile loadings. In order to experimentally investigate biaxial fracture behavior, cruciform specimens were prepared using electrochemical method, based on Lionel proposed model. The specimens were gridded by electrochemical etching method. A dependent biaxial tension mechanism was also designed and fabricated with relatively high precision machining methods. Installing the mechanism on an INSTRON-1343uniaxial machine, the experimental biaxial tests were performed at ambient temperature and strain rate of 0. 0003 $sec^{-1}$. Different aspects of the facture behavior, which may be of more interest to study, include initiation and development of fracture pattern, fracture path on the specimen section, and the force diagram for each of the arms. ABAQUS commercial software was utilized to simulate the biaxial tension test. Damage model was incorporated into the FE simulations to enable the FE model to capture the fracture occurrence in the cruciform specimen. Displacement loading with different ratios was applied to the specimen arms in the FE model to study the effect of loading ratio on the fracture of the material. Experimental and numerical results for location of crack initiation, path of crack growth and also the arms force diagram were compared and a good correlation was observed between. The experimental results reveal that the fracture grows along the corner-to-corner diagonal line, in the test section zone of the specimen. Simulation results show that minimal strains occur in the test section zone, near the arms. Experimentally measuring the fracture stress is one of the great challenges, and hence, numerical simulation would be very useful in this regard. Maximum of stress gradient in the simulation results is observed along the corner-to-corner direction, in the test section zone. Based on the simulation results, some fracture biaxial points were obtained in the first quarter of the biaxial stress plane subspace. These fracture stress point can be used to determine the material fracture loci in the first quarter of the biaxial stress plane subspace.

This study was conducted to investigate the effect of adding titanium diboride (TiB2) nanoparticles on the microstructure and tensile properties of the Al5083 matrix composite. Al5083/TiB2 metal matrix composites (with 5 and 10 wt % reinforcement) along with zirconium (Zr) and cerium oxide (CeO2) additives with different wt % were fabricated by in situ-stir casting at 1000 °C. The samples were then subjected to hot extrusion for uniform distribution of reinforcements in the matrix. TiB2 nanoparticles were in-situ processed in molten aluminum using the precursors such as cryolite (Na3AlF6), titanium oxide (TiO2), and potassium tetrafluoroborate (KBF4). The microstructure, surfaces, and failure mechanism of the samples were investigated using X-ray diffraction (XRD), optical microscopy (OM), and scanning electron microscopy (SEM). Tensile test results showed that the addition of 10 wt % TiB2 particles increased the ultimate tensile strength by 17.7 % and decreased the strain by 19.2 % compared to the sample without reinforcement. Besides, the addition of Zr and CeO2 increased the strength by 35.8 % and the strain of the sample containing 78 % by 10 % reinforcement compared to the sample without reinforcement due to the removal of intermetallic compound Al3Ti and the incompatibility between coefficients of thermal expansion (CTE) with the matrix. Also, post-extrusion annealing in the sample with 10 wt % TiB2 reduced the tensile strength.

Microstructural evolution and mechanical properties of in-situ Al5083 composites with 1 and 5 volume percent of TiB2 reinforcement particles were investigated. It was revealed that hot extrusion process results in a uniform, more homogeneous and less clustered structure of TiB2 particles compared with the as-cast structures. Scanning electron microscopy showed that TiB2 particlesin the Al5083-1 vol% TiB2 composite have a nearlyequiaxed morphology and round shape with an average size of ~ 0. 5 μ m. While, the morphology of TiB2 particlesin Al5083-5 vol% TiB2 composite is hexagonal with an average size of ~ 2 μ m. Also, the grain size reduces by adding TiB2 reinforcement particles to the Al5083 alloy. It was shown that the hardness, yield strength, young’ s modulus, and ultimate tensile strength of the Al5083-TiB2 composites increase with increasing TiB2 content. This can be attributed to the effect of TiB2 particles as a high hardness reinforcement phase and also the smaller grain size of the matrix which was resulted by adding the TiB2 particles.

The most prominent feature of sheet material forming process is an elastic recovery phenomenon during unloading which leads to springback. Therefore, evaluation of springback is mandatory for production of precise products. In this paper, the effects of temperature, friction coefficient, blank-holder force and sheet thickness on the springback of AL5083-H111 alloy sheet in warm U-bending conditions were investigated by performing experimental tests and numerical method. ABAQUS FEA software was used for numerical simulation. Finally, comparison of experimental and numerical results showed good agreement.

This study, the effect of adding zirconium diboride (ZrB2) nanoparticles on the microstructure and tensile properties of Al5083 aluminum matrix composite was studied. Al5083-5wt% ZrB2 and Al5083-10wt% ZrB2 nanocomposites were produced by situ-stir casting at 1000°C using in-situ synthesis. Then, the samples were subjected to hot extrusion for uniform distribution of the reinforcements in the matrix. The ZrB2 nanoparticles used in this study were processed in situ using cryolite (Na3AlF6), zirconium oxide (ZrO2) and potassium tetrafluoroboride (KBF4) in molten aluminum. X-ray diffraction (XRD), optical microscopy (OM) and field emission scanning electron microscopy (FE-SEM) were used to investigate the microstructure, surfaces and fracture mechanism of the samples, and tensile testing was used to evaluate the mechanical properties. The tensile test results showed that the addition of 10% by weight of ZrB2 particles, compared to the sample without reinforcement, increased the ultimate tensile strength by 18.2% and reduced the strain by 19.5%. Also, the additional extrusion process reduced the porosity resulting in increased density.

In the present research, electroless Ni-P deposits were obtained on Al5083 substrate and the effects of the coating time on morphology, phosphorus content and corrosion behavior of the deposits were investigated. The scanning electron microscopy (SEM) of specimens obtained in various coating times, were studied and compared in their surface morphology, thickness and uniformity of the coatings. Surface morphology of the coatings exhibited a nodular feature with a typical cauliflower-like structure. Corrosion resistance of the coatings was evaluated in 3.5 wt.% NaCl solution by potentiodynamic polarization and electrochemical impedance (EIS) methods. The results indicated that by increasing thickness of coatings, the number of porosities decreases and the corrosion resistance and coating thickness increases. The corrosion resistance of electroless deposits on a smooth substrate in comparison to a rough substrate is higher, probably due to the fact that by increasing substrate surface roughness, the number of defects and porosities of the coatings increas.