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sem-analysis
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Influence of tool geometry and contact condition on friction stir welding of Al-Cu laminated composites
, Article Advanced Materials Research ; Vol. 856 , 2014 , pp. 16-21 ; ISSN: 10226680 ; Kazeminezhad, M ; Kokabi, A. H ; Alvani, S. M. J ; Verdera, D ; Loureiro, A ; Sharif University of Technology
Abstract
In this study friction stir welding of Al-Cu laminated composites were carried out by two different tool geometries. Welding procedure was carried out from both sides of Al and Cu. Analyzing cross section of welds showed that different contact conditions between shoulder and material, offers different material flow behavior which is dependent on the tool geometry. SEM analyses showed that mixing of materials in nugget region is more pronounced in the advancing side. Also XRD results indicated that welding from Cu side, leads to intermetallic formation in mixed regions
Experimental investigation and probabilistic models for residual mechanical properties of GFRP pultruded profiles exposed to elevated temperatures
, Article Composite Structures ; Volume 211 , 2019 , Pages 610-629 ; 02638223 (ISSN) ; Houshmand Khaneghahi, M ; Ahmadie Amiri, H ; Esmaeilpour Estekanchi, H ; Ozbakkaloglu, T ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Here, we investigate the influence of elevated temperatures with negligible ambient oxygen on mechanical properties of various embedded glass fiber reinforced polymer (GFRP) profiles, as well as the application of a predictive Bayesian model for predicting these properties. Both the flexural and compressive properties of FRP profiles were investigated through the tests of I-shaped and box-shaped profiles. To determine the impact of low and high elevated temperature, the profiles were exposed to a wide range of temperatures (i.e., 25–550 °C); effects of the exposure time were also investigated. Experiments showed that specimens exposed to higher elevated temperatures for longer time periods...
Fabrication or preparation and characterization of new modified MCM-41/PSf nanocomposite membrane coated by PDMS
, Article Separation and Purification Technology ; Volume 80, Issue 3 , August , 2011 , Pages 556-565 ; 13835866 (ISSN) ; Pakizeh, M ; Shafiee, A. R ; Mansoori, S. A. A ; Sharif University of Technology
2011
Abstract
MCM-41 nanoparticles were prepared by in situ assembly of inorganic precursors and CTAB. The structure of nanoparticles was characterized by XRD, TEM, particle size analysis, N2 adsorption techniques. The surface modification of particles in order to perfect dispersion in polysulfone (PSf) matrix was performed by dimethyldichlorosilane (DMDCS) and aminopropyltrimethoxysilane (APTMS) as new modification agents. Thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and SEM analysis were applied to investigate thermal stability, glass transition temperature and quality of distribution of particle in the nanocomposite membrane, respectively. The PDMS was used to coat the...
Coating of graphite flakes with MgO/carbon nanocomposite via gas state reaction
, Article Journal of Alloys and Compounds ; Volume 500, Issue 1 , June , 2010 , Pages 74-77 ; 09258388 (ISSN) ; Faghihi Sani, M. A ; Golestani Fard, F ; Saberi, A ; Soltani, A. K ; Sharif University of Technology
2010
Abstract
Coating of graphite flakes with MgO/carbon nanocomposite was carried out via gaseous state reaction between mixture of Mg metal, CO gas and graphite flakes at 1000 °C. XRD and FE-SEM analysis of coating showed that the coating was comprised of MgO nano particles and amorphous carbon distributed smoothly and covered the graphite surface evenly. Thermodynamic calculations were employed to predict the reaction sequences as well as phase stability. The effect of coating on water wettability and oxidation resistance of graphite was studied using contact angle measurement and TG analysis, respectively. It was demonstrated that the reaction between Mg and CO could result in MgO/C nanocomposite...
Tribological characteristics of rubber-based friction materials
, Article Tribology Letters ; Volume 41, Issue 2 , October , 2011 , Pages 325-336 ; 10238883 (ISSN) ; Shojaei, A ; Sharif University of Technology
2011
Abstract
This article deals with the rubber-based friction materials (RBFMs) which can be used in brake system. The physico-mechanical and tribological properties of a series of fiber filled RBFMs containing steel wool and aramid pulp at different concentrations along with a fiber-free reference material were characterized. Rubber-glass transition induced at higher sliding velocities was identified based on the friction fade behavior of the RBFMs. The rubber-glass transition which is inherently originated by viscoelastic response of polymeric binder was found to be influential on the tribological properties of the RBFMs. It was revealed that steel wool increased coefficient of friction (COF) and...