In this paper, the forming process of a central hub by radial-forward extrusion is analyzed by using the finite element software, ABAQUS. Radial-forward extrusion is used to produce hollow parts that generally feature a central hub with radial protrusions. Effective design factors such as mandrel diameter, die corner radius, die fillet radius, mandrel corner radius, tube wall thickness and frictional conditions on the force required are investigated by simulation process. Commercially pure aluminum AA1100 is selected as a model material for both experimental investigation and simulation analysis. Comparison is made and good agreement between the experimental result and that of finite element method is achieved.

Implantation of nitrogen in aluminum has been investigated by many authors and the results are partly different. In this study nitrogen ion implantation at doses from 4x1017 to 1X1019 ions/cm2 and energy of 80 keV in pure aluminum without any thermal annealing is investigated. By means of x-ray diffractometry the phase composition was characterized. Nitrogen and aliminium nitride distribution in samples at different doses was analyzed using SIMS. Hardness of samples before and after implantation was tested by Vickers instrument. The results show that the hardness of samples after ion implantation process and because of formation of aluminium nitride phase increases dramatically, but aho\e the dose of  5x1018 ions/cm2 it decreases.

In this study, GTAW process and cored wires were used to coat Al/Al3Ti wear resistant composite on a Commercial pure Al substrate. Wire drawing process was utilized to produce the cored wires from aluminum strips and a mixture of titanium and aluminum powders. The microstructures and the present phases were investigated by metallographic, SEM equipped with EDS and XRD analysis. Moreover, the hardness and wear resistance of the samples were evaluated. A maximum micro hardness value of about 300HV was measured which is 13 times higher than the hardness of the substrate material. The results showed that the coating was composed of Al, Ti as well as Al3Ti. The presence of Al3Ti led to increase in the wear resistance of the coating.

In this work, Boltzmann transform has been used to analyze the problem of freezing ‎of pure aluminum in semi-infinite domain. The uniqueness of solution (solidification ‎front location) has been proved using the characteristics of the functions appeared in ‎solution. The effect of density change on temperature distribution and errors resulting ‎from ignoring this change have been investigated. The solidification problem in finite ‎media was solved using the boundary element method (BEM), with quadratic shape ‎functions. The applicability of the fundamental solution, as weighting function in ‎BEM, in finite domain has been investigated. The accuracy of the method is ‎illustrated through one-dimensional numerical examples. Some careful experiments ‎were carried out, using the facilities of the School of Metallurgy and Materials at the ‎University of Birmingham, UK, to obtain the data. Comparison of theoretical, ‎numerical and experimental results revealed that good agreement exists between ‎them. However, minor differences were observed due to imposing of the simplifying ‎boundary conditions. The effects of density change may be ignored in small volumes, ‎but they must be taken into account in real applications‏.‏

Fabrication of ultrafine grained materials by imposing severe plastic deformation for improvement of mechanical and physical properties of metals has been the focus of many researches over the past few years. In this process, a sheet is subjected to repetitive shear deformation conditions by utilizing asymmetrically grooved and flat dies through alternate pressing. In this study, a 2mm thick Commercial pure aluminum sheet was subjected to repetitive pressing up to four passes. Mechanical properties including, hardness and tensity were obtained.Results show that, although increasing the number of passes causes higher strength magnitude, the strength’s slope decreases. After validation of finite element modeling, strain distribution and uniformity behavior of the grooved plate were investigated using plain strain and plain stress conditions. Results show that strain in the surface and near the teeth of the die is lower than other areas.

In this work, Commercial pure aluminum was subjected to friction stir processing (FSP) up to six passes, then, mechanical properties, electrical conductivity, and microstructure analysis of the processed samples were compared with the initial condition. Better yield strength, ultimate tensile strength, and hardness are achieved after imposing the process. Also, strengthening rate is reduced at the subsequent passes. It was found that hardness magnitude is decreased mildly by getting away from the center. Although material formability is reduced after the first pass, it is grown a little by adding the pass number. The microstructure analysis indicated that application of one pass FSP changes considerably grain size of the annealed aluminum and leads to extreme decrease of the high-angle grain boundaries density which plays the main role in the reduction of electrical conductivity. Addition of FSP pass number leads to increment of dislocations density, transformation of low-angle to high-angle grain boundaries, and the further intersection of shear micro bands, causing improvement of sample formability and electrical conductivity compared to the first pass. Therefore, this process has the capability for fabrication of pure aluminum with improved mechanical properties and acceptable electrical conductivity.

Three mm thick plates of Commercial pure copper were welded via friction stir welding method using a floating bobbin tool. The effect of different process variables such as the tool transverse speed and the tool rotation speed were examined in order to create a weld with the desired properties. A defect-free weld was obtained at a rotation speed of 1400 rpm and a transverse speed of 18 mm/min with a shoulder pinching gap of 2. 7 mm. After the welding process, the soundness of the welds was confirmed by non-destructive methods of visual inspection and X-ray radiography. The results of the transverse tensile test showed that the as-weld joint efficiency was 86. 4%, which was higher than the joint efficiency made by the fusion welding method. The strength of the welds was such that the fracture of the workpiece was in the heat affected zone after the tensile test. On the other hand, the grain size of the weld was significantly less than the base metal. The lowest hardness around 40VHN was attributed to the middle of the thickness of the weld, while the highest hardness was in the vicinity of the lower shoulder of the tool, which was about 80 VHN.

With development of computer science, numerical methods have been used for the simulation of laboratory and industrial processes. Prediction of material microstructures is one of the processes of great interest to material designers since the property and performance of materials depend strongly on their microstructures. The Monte Carlo method, as a physical-statistical approach, has been utilized to predict microstructures in the last two decades. In the present paper, the Monte Carlo method is used to investigate the normal grain growth in pure aluminum and the grain growth exponent of metals. A 150 x 150 two dimensional triangular lattice is utilized to analyze the process. It was found that there is a good agreement between the mean exponent of the parabolic growth law and simulation results. The grain growth of aluminum microstructure was calculated at the certain temperature using the grain growth law and compared with the simulation results by varying the Q as a parameter of lattice orientation. It was found that increase in Q increases the accuracy of the predicted results.

Titanium alloys are widely used in many fields such as the automotive, aerospace and chemical industries. In some applications, titanium alloys are needed for use with particular welding methods. These are GTAW, GMAW and laser welding. In this study, titanium Grade- 2 (Cp-Ti) plates were welded using Laser welding and GTAW. Tensile and flexural tests were applied to the welded samples. The microstructure and SEM images of main material and welded regions were studied and micro hardness measurements were performed. Tensile and flexural strengths of laser welded samples were higher than GTA welded samples. The micro hardness values of the weld-zone of laser welded samples were lower than the GTA welded samples welding zone. In microstructure and SEM investigations, oxide structures and the splashes of molten metal appearing like drops were identified. The width of the weld-zone in laser welding was in a narrow range.

Due to their excellent mechanical, electrical and thermal properties and ease of production, metallic bipolar plates are a suitable replacement for graphite and composite plates. Stamping is one of the most applicable processes to produce theses plates from a manufacturing cost point of view. Due to its excellent corrosion resistance and low density, titanium rises as a potential option for the manufacturing of the bipolar plates. In this paper, the formability of titanium bipolar plates having a thickness of 0. 1mm with a parallel flow field has been experimentally investigated. The formability of the sheet was evaluated at warm temperatures using different forming speed and lubricants. After the experimental implementation of the designed tests based on the Taguchi method, the fracture depth of the microchannel of stamped samples was extracted. The results showed that the most elongation of the sheet will be achieved at 100℃ . Likewise, the forming speed and temperature are the most effective parameters on the forming depth, respectively. On the other hand, the effect of the lubricant is not tangible compared to the other mentioned parameters. The maximum forming depth equal to 0. 494mm was obtained using an experiment with a forming temperature of 100℃ , speed of 4. 8mm/min, and lubrication with MoS2.