In this study, aluminide coating was employed to enhance the high-temperature cyclic oxidation of Rene-80 superalloy at 950º C. The Microstructural aspects and phase constituents of samples were investigated with scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques. The result of oxidation tests showed that the weight gain in the uncoated sample was considerably higher than the aluminide coated sample, which indicates the higher rate of oxide formation on the uncoated surface. With the aid of Microstructural and XRD analysis, it was confirmed that with the increment of oxidation cycles, the thickness of aluminide coating reduced and the protective β-NiAl phase was converted to alumina scales. According to the EDS results taken from the top coat, it was found that with the increase of oxidation cycles, the content of aluminum in the top layer was drastically decreased and the weight percentage of oxygen was considerably enhanced. Also, in higher oxidation cycles, other protective elements such as Cr and Ti outwardly diffused from the inter-diffusion zone (IDZ) layer which led to reduction in the content of these elements in inner zones of the aluminide coating.

In this study, the effect of joints design geometry on the Microstructural aspects and corrosion mechanism of weld metal in the Hadfield steel welding joints was investigated. For this purpose, initially 4 austenitized sheets of Hadfield steel with 2mm thickness prepared. Then joints design with two chamfered V and X forms were prepared and SMAW process was used for welding. In the next step, potentiodynamic polarization and electrochemical impedance spectroscopy methods were used to evaluate corrosion behavior of welded joints weld metal in the 3.5% NaCl solution. Also optical microscopy method was used to evaluate the microstructure of weld metal, Corrosion morphology of weld metal were investigated by scanning electron microscopy and X-ray diffraction was used for the analysis of phases formed in the microstructure if weld metal. The results indicated that with using joints design containing chamfered Vshape in comparison with joints design containing chamfered X-shape in the Hadfield steel welded joints, resulted microstructures consisted from smaller grains and more carbide precipitates. The results indicated that V-shaped chamfers in comparison with X-shaped chamfer led to reduction in corrosion resistance and changed weld metal corrosion mechanism from uniform corrosion to localized micro-galvanic corrosion in the Hadfield steel weld joints.

In this study, zirconia coatings have been prepared by atmospheric plasma spraying under different parameters in air on mild carbon steel substrates. The effects of spraying parameters; powder feed rate and spraying distance (SD), on Microstructure of 8wt%Y2O3-rZrO2 (YSZ) coatings were studied. Measurements were made on specimens in the as- sprayed state. The microstructures of coatings were analyzed by optical microscopy (OM) and scanning electron microscopy (SEM). Phase analyses of the YSZ powder/coatings were examined by X-ray diffractometer (Rigaku, Tokyo, Japan) operating with Cu Ka and the size and amount of their porosity were evaluated using an Image Analysis method. The results showed by varying spray distance/ powder feed rate, significant changes were detected in the microstructure of the top coat. The total porosity, pore morphology and unmelted particles are correlated with the powder feed rate and spray distance. Also, It was found that the powder feed rate has a larger effect on the coating microstructure than the spray distance in the conditions investigated.

Combined effects of homogenization pressure (0, 50, 150 bar), homogenization sequence (before or after heat treatment), and type of stabilizers (carrageenan, guar and a mixture of carrageenan – guar, either alone or in the presence of starch) on the textural and rheological parameters, including hardness, viscosity, surface tension, syneresis and also Microstructural properties of cream – based dairy dessert were investigated. Homogenization pressure of 50 bars after and 150 bars before heating resulted in the highest and lowest hardnesse, respectively. Homogenization pressure of 50 bars after heating led to the highest surface tension, whereas the lowest obtained when applying 150 bars of pressure following the process of heating. Unhomogenized treatments exhibit the highest syneresis, vise versa; the lowest amount was primarily related to the homogenized treatments (after heating) and secondarily homogenized treatments (before heating). Using carrageenan, alone, caused both the highest hardness and the highest syneresis, and in mixture with guar, the highest surface tension. Guar, alone, led to the lowest hardness, surface tension and syneresis. In the presence of starch, hardness was increased using all three combinations of gums, but surface tension was increased through only carrageenan - guar mixture application. Syneresis was decreased applying carrageenan, alone. Microstructure analysis showed good correspondence with the textural and rheological results.

Eqhlid Shear Zone (ESZ) located on 230 Km north of Shiraz City and 45 Km southeast Eqhlid City. This area is part of the Sanandaj-Sirjan paired metamorphic zone, which have been affected by brittle-ductile and ductile deformation. Metamorphic rocks of this area are mainly composed slates, phyllite, metasandstone, crystalline limestone, metadolomite, metavolcanics, and mylonite.In Eqhlid area, several thrust and duplexes are present with NW-striking and NEdipping. The main thrust in area is ESZ. The shear zone and associated thrust and folds are portion of the Main Zagros Thrust orogenic belt and they are parallel with this belt. Observation en-echelon, folded boudinage and asymmetrical folds in mesoscopic scale indicate dextral shear sense of the ESZ.Microscopic studies of the S-type and C-type shear band cleavages and mantled prophyroclasts confirm dextral shear sense. These microstructure formed in greenschist facies conditions.The current studies of kinematics and geometry of thrust and strike-slip faults and shear zone plus micro-structures such as S-C fabrics and asymmetrical folds display dextral oblique transpression of the Afro-Arabian convergence.

Today, in order to reduce the harmful effects of the environment and increase the mechanical properties and durability of concrete, particles with high pozzolanic properties are used as a suitable alternative to ordinary cement in concrete. And filler, as an alternative to cement, has attracted the attention of researchers. In this laboratory study to investigate the effects of slag and nanosilica slag consumption on the microstructure of geopolymer concrete and compare it with the characteristics of control concrete containing Portland cement, 1 mixing design of control concrete and 3 mixing designs of geopolymer concrete containing 92, 96 and 100% composite kiln slag was fabricated with 0, 4 and 8% nanosilica, respectively. X-ray fluorescence (XRF) was performed. In order to investigate the effect of Microstructural changes on the macro structure of concrete, compressive strength and tensile strength tests were performed on concrete samples at 90 days of age. Examination of the images obtained from the SEM test shows the superiority of the microstructure of the geopolymer cement matrix in all designs, compared to the microstructure of the control concrete containing Portland cement. Celsius), the effects of improvement and cohesion in the microstructure of geopolymer concrete are evident due to the presence of silica nanoparticles, in this regard, the presence of 8% nanosilica in mixture 4 (geopolymer concrete), accelerates the reactivity process and increases the volume of hydrated gels Geopolymerization was compared to other geopolymer concrete mixtures (containing 0 and 4% nanosilica). Images of concrete samples heated to 500 ° C show signs of weakening of the concrete microstructure compared to images taken of concrete at room temperature. The results of XRF test indicate the presence of the highest amount of oxidilica and aluminum oxide (the main factors in improving the density in the microstructure of concrete), in the combination of designs 4 and 2 by 36 and 8%, respectively. The high peaks created in the XRD spectrum diagram often occur in areas with angles (θ2) of 28 °, and their height varies according to the presence of aluminosilicate particles in the concrete mix. The application of high heat to the concrete specimens caused a decrease in the results of the XRD test. Evaluations performed on the results of the test to determine the compressive strength and tensile strength in concrete, showed coordination and overlap with the results of Microstructural tests in this study.

In this research, after pressing in a cylindrical mold, the AA 7075 alloy swarf was melted and cast in a wet sand mold. After rolling and cutting, sheets with two different thicknesses of 6 and 20 mm were obtained. The sheets after homogenization were solutionized at 485°C for 30 and 90 minutes, respectively, due to differences in thickness and thermal gradients. The solutionized samples were quenched in 3 polymer solutions containing 10, 30, and 50% Poly Alekylene Glycol. The results showed that melting, casting, rolling, and heat treatment of AA7075 alloy swarf similar properties to this alloy is achievable. Microstructural studies by optical microscopes (OM), Field Emission Scanning Electron Microscopy (FESEM), and X-ray diffraction (XRD) showed that by increasing the quenching rate after the solutionizing process, precipitation increases during aging. The tensile test results indicated that as the quench rate and internal energy increase, the diffusion driving force would increase the precipitation of alloying elements. Hence, this leads to an increase in hardness and reduction of its strain after aging.