Localized corrosion of aluminum alloys is often triggered by intermetallic particles, IMP’s. To understand the role of IMP’s in corrosion initiation of EN AW-3003, efforts were made to combine nano-scale ex-situ analysis ofthe IMP’s by SEM-EDS, SKPFM and in-situ AFM monitoring of the localized attack in chloride containing solution. The results showed that two distinct types of eutectic ally-formed constituent IMP’s exist; the -Al(Mn, Fe)Si and the Al (Mn, Fe) phases. However, the exact chemical composition of the IMP’s varies with the particles size. Volta potential difference of surface constituents revealed that IMP’s have a higher Volta potential compared to the matrix, indicating the cathodic characteristic of the IMP’s. Noticeably, the boundary regions between the matrix and IMP’s exhibited aminimum Volta potential probably the sites for corrosion initiation. Localized corrosion attack monitored by in-situ AFM clearly showed the trench formation occurrence around the large elongated IMP’s in the rolling direction.

In this study, optimization of advanced square wave alternative current GTAW(ASW-AC-GTAW) parameters were conducted to improve localized corrosion resistance of AA6082-T651 aluminum alloy welds. To this objective, positive half cycle current(PHC), negative half cycle current(NHC), frequency(F) and positive half cycle current percentage(PHC%) were selected as main welding parameters and altered at three levels according to Taguchi method and L9(34) orthogonal array. To study the localized corrosion resistance of weld metals; potentiodynamic polarization test was performed on all samples and corresponding Δ Epit(𝐸 𝑝 𝑖 𝑡 − 𝐸 𝑐 𝑜 𝑟 𝑟 )(𝑚 𝑉 ) were measured and considered as evaluation criterion. Implementation of variance analysis(ANOVA) on measured data and SN⁄ (Signal-to-Noise) ratios indicated that the optimum levels of PHC, NHC, F, and PHC% were 300A, 190A, 2Hz, 40%, respectively. According to ANOVA of SN⁄ ratios, contribution of PHC, NHC, F, and PHC% to the results were 35. 05%, 25. 98%, 23. 57%, and 15. 27%, consecutively. Interval domain for average Δ Epit calculated with 95% confidence level to be (379. 4, 386. 54) (mV). confirmation sample was welded under optimum condition. The values of Δ Epit of optimum sample were 381. 13 and 385. 47 mV. Both of this measurement fallen in the Interval domain. Therefore, the experimental results were in excellent agreement with analytical predictions. The regression model for predicting 𝛥 𝐸 𝑝 𝑖 𝑡 values was obtained using multivariate nonlinear regression.

In this research, the corrosion of API 5L 42X steel in contact with rock wool thermal insulation at four temperatures 20, 40, 60 and 80oC is investigated. For this purpose, the tafel polarization, cyclic polarization and weight loss examinations were used. Electrochemical and weight loss tests were conducted in insulation’s leachate and in contact with wet insulation, respectively. Furthermore, in order to confirm of corrosion tests results, the corrosion products that obtained from weight loss measurements at 20 and 80oC, were evaluated by X-ray diffraction (XRD) analysis. The results of tafel and weight loss examinations for 20oC showed that rock wool insulation alone had little talent in the corrosion creation on steel samples, which this outcome of the alkaline nature of it’s leachate and low chloride ion concentration in this insulation. In weight loss measurements due to formation of a close system, by the increase of temperature from 20 to 80oC, the corrosion rate continuously was increased, while such behavior because of formation of an open system was not observed for tafel tests in the temperature range of 60 to 80oC. Cyclic polarization tests and microscopic observations of samples surface after weight loss measurements have shown that the increasing of temperature is increased the tendency to localized corrosion.

Corrosion is a major challenge for the performance and health of structures. Structures in offshore, industrial, and urban settings corrode due to humidity, pollutants and various chemical agents, leading to performance reduction. plate girders have been increasingly used, and the web corrosion of such girders reduces their shear strength. This study evaluated the shear strengthening of corroded plate girders using different stiffener patterns. Corroded and non-corroded plate girders were nonlinearly analysed in ABAQUS. corrosion was modeled through thickness reduction in the numerical models. Uniform, pitting, and groove corrosion patterns as large as 25-75% of the web thickness were considered. Stiffeners were employed to strengthen the corroded plate girders. The effects of different stiffener parameters, including shape, size, and spacing, were investigated. It was found that a 50% web thickness reduction due to corrosion could decrease the shear strength of the plate girder by 47%. Pitting corrosion in the top and bottom of the web led to a 36% shear strength decline, and the top corrosion was more critical than the bottom corrosion. Flange-web disjoining due to groove corrosion diminished shear strength by 55%. Vertical stiffeners enhanced the strength of the plate girder by 54%. The results showed that T-and L-shaped stiffeners outperformed rectangular stiffeners under the same conditions.

Adding some alloying elements such as copper and zinc into aluminium and appling precipitation hardening process, makes these alloys sensitive to different types of corrosion in marine atmospheric environments. Precipitates on the matrix and grain boundaries are the main factor for corrosion. In order to study the corrosion behavior of metals in marine atmospheric environments, simulated environmental conditions is required to provide severe atmospheric environments containing chloride ion. In this research, a new method is used to study the atmospheric corrosion. At first specially prepared samples were tasted in corrosion cells with different time periods that the salt crystals were placed on the surface of samples and end grain areas on sample thickness were investigated. In this situation 100% relative humidity condition was stable. The microscopic studies showed that the intergranular corrosion happened less than 72 hours in 7075 alloy because of presence of deposits in grain boundaries and after this time, intergranular corrosion transform to pitting and exfoliation corrosion. Uniform corrosion with small pits was stable for 2024 alloy and the corrosion rate for 6061 alloy was lower than 2024 and 7075 alloys. Finally In order to compare the corrosion behavior of surface, the alloys were placed into the salt spray test for 672 hours according to ASTM B117. In this situation, 2024 alloy had the highest rate of corrosion.

The subject of “globalization in literature” is often difficult to assess. When can a literary work be called “globalized” and to what extent is it? The works of the modern Persian writer “Goli Taraghi” have on the one hand characteristics of globalization, on the other hand they are deeply rooted in the “local”. The two-sided nature of these works and their boundary between “global” and “local” is illustrated in this article using examples and explanations. On the one hand, these works can be described as global literature due to the translations in different languages and also the living conditions of the writer, who studied as a young girl in the USA and has lived mainly in Paris for more than forty years, on the other hand, they are deeply rooted in childhood memories Taraghis and the traditions of a wealthy Tehran family and Iranian culture. In some narratives, both characteristics are found to be parallel and interwoven, elements of modern western life that partly influence the traditional of Iranian culture, partly form a strong contrast and seem incompatible. Globalisiert lokalisiert – lokalisiert globalisiert? Moderne Werke von Goli Taraghi Zusammenfassung Das Thema der „Globalisierung in der Literatur“ ist oft schwer zu bewerten. Wann kann ein literarisches Werk als „globalisiert“ bezeichnet werden, und in welchem Ausmaß? Die Werke der modernen persischen Schriftstellerin Goli Taraghi weisen einerseits Merkmale der Globalisierung auf, sind andererseits aber tief im „Lokalen“ verwurzelt. Diese Zweiseitigkeit ihrer Werke und die Grenzziehung zwischen „global“ und „lokal“ werden in diesem Artikel anhand von Beispielen und Erläuterungen veranschaulicht. Einerseits können diese Werke aufgrund der Übersetzungen in verschiedene Sprachen und der Lebensumstände der Autorin – die als junges Mädchen in den USA studierte und seit über vierzig Jahren überwiegend in Paris lebt – als Weltliteratur bezeichnet werden. Andererseits sind sie tief verwurzelt in den Kindheitserinnerungen Taraghis sowie in den Traditionen einer wohlhabenden Teheraner Familie und der iranischen Kultur. In einigen Erzählungen sind beide Merkmale parallel und ineinander verwoben: Elemente des modernen westlichen Lebens, die die traditionellen Strukturen der iranischen Kultur teilweise beeinflussen, teilweise aber auch in starkem Kontrast zu ihnen stehen und unvereinbar erscheinen. Schlagwörter Globalisierung der Literatur – lokale Literatur – Nostalgie – moderne Erzählungen – Goli Taraghi

V-shaped steel plates are utilized in the construction of various structures, including roofs and walls of buildings, warehouses, ships, beams and girders, airplane hangars, and military vehicles, due to their lightweight and high strength. Studying the free vibration behavior of these plates is significant for understanding the true performance of structures. Exposure to unfavorable weather conditions can lead to corrosion phenomena. The impact of corrosion on the geometric and mechanical properties of steel structures can result in severe damages, including partial destruction of the structure or its collapse over time. This phenomenon highlights the importance of examining and analyzing corroded structures. For this purpose, this research analyzes the frequencies and modes of various V-shaped plates with uniform, strip, or localized corrosion under different boundary conditions, including free, hinged, and fixed conditions, with corrosion intensities of 2.90%, 8.90%, and 15.70%, respectively. The finite element software Abaqus has been used for modeling and data analysis. The results indicate that corrosion typically leads to a reduction in frequency values and changes in the modes of the plates. For example, for a plate with a length of 2 meters, a width of 1 meter, a thickness of 20 millimeters, an internal angle of 45 degrees, and four-sided hinged boundary conditions, the frequencies for corrosion intensities of 2.90%, 8.90%, and 15.70% are 90.04, 84.76 and 77.45 (Hz), respectively.

In this study, the effect of Al on the corrosion resistance of Hadfield steel weld joints’ fusion zone was investigated. For this purpose, 4 austenitized sheets (two sheets without Al and two sheets containing 1. 7wt. %Al) with thickness 2mm prepared from Hadfield steel and then SMAW process was used for welding. Then potentiodynamic polarization and electrochemical impedance spectroscopy methods were used to evaluate corrosion behavior of welded joints’ fusion zone in the 3. 5wt. %NaCl solution. The evaluation of the microstructures of weld metal in welding joints were conducted by optical microscopy and the corrosion mechanism were determined by scanning electron microscopy examination. The result of corrosion tests indicated that welded joints’ fusion zone of Al containing plates were more corrosion resistant. Because Al addition increased the solubility of carbon in austenite phase and as a result factors enhancing localized micro-galvanic corrosion such as grain boundaries and carbides were reduced. However as clearly was visible in scanning electron microscopy images, using joints design containing Al in comparison with joints design without Al led to changed weld metal corrosion mechanism from uniform corrosion to localized micro-galvanic corrosion in the Hadfield steel weld joints.

This research is dedicated to the influence of different technological factors on wear and corrosion behaviors of flame sprayed Alumina-Titania coatings of low carbon steel substrate. Samples were studied using optical microscope, scanning electron microscope and x-ray diffraction method. Investigation showed that structure of coatings involved different allotropic forms of Al2O3 either stable phase (a) or meta stable phases (y,k) and TiO2. There were a low amount of MgO and SiO2 in the cord as self-fluxing agents and also as reducing agents for the melting point of alumina. Microhardness, wear and corrosion test were performed to characterize the coatings. Wear results showed that depending on each factor employed, wear resistance of coatings were different. Corrosion examination was performed as immersion extrapolation tafel tests at 3.5 % NaCl solution. Electrochemical examination results showed that corrosion rates of coated samples were obviously less than that of normal steel and immersion test results demonstrated that because of present of porosity and microcracks in the coatings, localized corrosion can occurre on the substrate.