The electrochemical behavior of 6063 aluminum ALLOY in ethylene glycol-water mixture was investigated by polarization curves and AC impedance measurements (EIS). The results obtained from polarization curves showed that corrosion rate decreased with increasing ethylene glycol concentration. EIS data showed the decrease in the interface capacitance which caused by adsorption of ethylene glycol at the surface of aluminum ALLOY. The cathodic current increased with the increase in rotating speeds of solution and the anodic current decreased. The effect of temperature was studied and the corrosion rate was increased with increasing the temperature. In addition, thermodynamic parameters were calculated in different ethylene glycol concentrations.

The relatively new solid state welding process friction stir welding (FSW) was applied in this research work to join similar and dissimilar aluminum ALLOYs AA5754-H22 and AA6063-T4. Different welding rotational speed and transverse speed applied. The joint which was fabricated using tool rotational speed of 2000 rpm and transverse speed of 4 mm/min yielded the best mechanical properties. Soundness of joint was proved by non-destructive tests such as visual inspection and radiography. The global mechanical behavior of the similar welds is very similar to that of the base material. For dissimilar weld important losses in ductility was reported. Microstructural evaluation of fractured surface showed that ductile fracture was the major fracture mechanism of similar and dissimilar welds.

In the present study, metallurgical tests including quantometry, X-ray diffraction analysis, and microstructural investigations with optical and scanning electron microscopes were emplyed to investigate the effect of composition and microstructure on the mechanical properties of the cast ingots and extruded profiles manufactured in Balouch Aluminum Company. Results showed that the concentrations of Fe, Si and Cu were higher than the standard composition of 6063 Al ALLOY. Optical micrographs sowed that pores were mainly observed at the center of ingots. According to XRD analysis, in addition to FCC phase, an iron aluminide intermettalic phase was identified in the structure of ingots. The formation of intermetallic phase was confirmed by energy dispersive analysis attached to the scanning electron microscope. Tensile test results illustrated that the presence of pores and the distribution of intermetallic phases declined the strength and formability of the ALLOY. The ultimate tensile strengths at the surface and center of the ingot were 103 and 71MPa, respectively. Fractography of samples indicated that the presence of pores and the intermetallic phase led to a combination of ductile and brittle fracture durin tensile test.

Due to the low formability of aluminum ALLOYs at ambient temperature, forming of these ALLOYs is performed at high temperature. Research has shown that the results of simple tensile test to predict the materials behavior at high temperatures are not sufficiently accurate to predict the formability of aluminum tubes at high temperature. The mechanical properties of the tube are very important at high temperatures. In this study the formability of 6063 aluminum ALLOY tubes are investigated by free bulging test at temperature range 430oC to 600oC. Then the mechanical properties including flow stress, strain rate sensitivity coefficient and strength constant are obtained using tube multi-bulge test at temperature range 530oC to 580oC. For this purpose, hot metal tube gas forming process is used and the effect of process parameters such as the effect of temperature, pressure and time on the expansion ratio and height of the bulge are studied. The results show that the maximum expansion ratio is 58% at 580oC. Bursting pressure decreases from 1.9MPa to 0.6MPa with temperature increasing from 430oC to 600oC. The bulge height increases with increasing forming time at constant pressure. Also, with increasing temperature in the temperature range 530oC to 580oC the flow stress and strength constant decrease and strain rate sensitivity coefficient increases.

The process of interference fit and bolt clamping force are two effective techniques for improving the fatigue life of the joints and are used in various industries, especially in aerospace and automotive. Most of the previous studies have investigated separate effects of the interference fit and bolt clamping force on the fatigue life of the specimens. In the present research fatigue behavior of interference fitted specimens combined with bolt clamping force has been investigated yet. On the other hand, the pervious researches on the interference fit and bolt clamping force have been studied at laboratory temperature and the effect of temperature changes has not been investigated. To investigate the effect of temperature on the fatigue life of specimens, two different temperatures (i. e. 60° C and 120° C), aside from room temperature, were selected and fatigue life of specimens are studid at these tempratures. The fatigue tests were performed on the specimens of Al-ALLOY 7075-T6 ALLOY to obtain S-N data.

In this paper, the severe plastic deformation by twist extrusion (TE) process is investigated. In this process, the workpiece is forced through a twist channel, which develops shear strains in the material. These shear strains result in a fine-grained structure in the material. For investigating the material deformation, the TE process was simulated in the Abaqus finite element (FE) software. The effects of backpressure and friction between the sample and channel were investigated. In the FE model, a sample of AA6063 aluminum ALLOY was formed in a twist channel with an angle of 45 degrees and a length of 16 mm. The FE simulation results were validated by conducting experimental tests. When the backpressure of 50 MPa was used, the sample was distorted, which improved by increasing the backpressure to 70 MPa. The highest strains occurred in the corners of the sample, which was about twice of the plastic strains obtained at the side edges of the sample. Furthermore, the calculated plastic strains in the central areas of the sample were very low (0. 042) in comparison to the strains developed in the corners and side edges of the sample.

The most important defect in casting of Al-5Cu-1Ag ALLOY is hot tear. To solve this problem, using new casting methods such as semi-solid casting process is in forth. In this research after ALLOYing process, samples were casted via common direct casting (DC) and semisolid casting (SC) methods. These samples were aged for 18 hours at 150oC. Microstructural studies were performed by optical and scanning electron microscopes equipped by EDS for elemental analysis and image analyzing by CLEMEX software. Mechanical properties were investigated by the use of Brinell hardness and tensile strength measurements results. Study on semi-solid behavior and determination of optimum solid fraction were performed by Thermo Calc Software. Results show that the dendritic structure in DC casted samples has changed to a 78% spherical structure with 48 mm diameter in SC method. Thus, hardness, tensile strength and elongation increased up to 50%, 20 % and 77 %, respectively. According to thermodynamically modelling results the optimum temperature range for rheocasting of Al-5Cu-1Ag ALLOY is 545-612oC.

The aim of current research was to examine the texture of annealed Al-7075 ALLOY that develops during Equalchannel angular pressing (ECAP) in different ECAP routes. After annealing heat treatment, the material was pressed up to 4 passes by route A and BC at room temperature. The effect of copper tube casing on the texture evolution was also investigated. The texture was studied by X-Ray diffractometer in ED-plane as well as TD-plane. The qualitative and quantitative analysis of the texture reveals that the texture of the first pass is relevant to initial texture, but by increasing pass number this dependency disappears and the texture is mainly relevant to processing route. The texture calculation by Labotex software shows that the results in both TD (z) and ED (x) planes are in good agreement and covering the specimens with copper tube causes a decrease in texture strength and microstructure inhomogeneity of the specimens.

Zinc based ALLOYs of the Binary system of Zn-Al have wide industrial applications, such as Bearing and Bushing. Various physical metallurgical principles of Zinc-rich ALLOYs have been fully investigated especially, their phase transformations near the room temperature. Less attention has been paid to the Al-rich ALLOY (with more than 20 wt% of Zn) of the same Binary system, especially quench - ageing processes, near the room temperature. In the present article, the phase transformations of the Al based ALLOY (with 30 Wt% of Zn) after the quench- ageing processes, natural and artificially aged at 100°C have been investigated, by mans of Electron Microscopy (T.E.M, S.T.E.M), Techniques. It has been shown that the high temperature supersaturated α' phase is transferred to the stable η- phase by the formation of G.P Zones and two transitional phases called α'm and α"m both with the F.C.C structures.

Plasma Electrolytic Oxidation (PEO) method was employed to enhance corrosion resistance of 7075 Aluminum ALLOY. The coating process carried out in a silicate based electrolyte by DC constant current density. Characteristics of coating were evaluated by X-ray diffraction and scanning electron microscopy methods. Analysis showed the formation of g-alumina oxide film, which has a porous surface and some pores in its structure. Coating corrosion behavior was evaluated by electrochemical tests after 1 hour immersion in 1M H2SO4. Tafel Polarization test revealed that PEO decreased the corrosion current density as ten orders of magnitude, and increased the charge-transfer resistance as twenty five order of magnitude, and thus improved corrosion resistance of 7075 Al ALLOY. Electrochemical Impedance spectroscopy (EIS) test revealed that the coating formed a physical barrier against the charge transfer, and decreased the diffusion rate of the corrosive solution due to its non-columnar structure.