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iron-alloys
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The correlations between processing parameters and magnetic properties of an iron-resin soft magnetic composite
, Article Journal of Magnetism and Magnetic Materials ; Volume 305, Issue 1 , 2006 , Pages 147-151 ; 03048853 (ISSN) ; Madaah Hosseini, H. R ; Kianvash, A ; Sharif University of Technology
2006
Abstract
In this study, internal microstrain of an iron-resin composite produced by powder metallurgy has been calculated using the Williamson-Hall method. The effects of microstrain evolution during different processing conditions on magnetic properties such as coercive force and hysteresis loss have been investigated. The results show that there are regular and similar changes of coercivity and hysteresis loss. Both of these properties are directly dependant on the pinning effect of the internal microstrain against the movement of magnetic domain walls during magnetization process. © 2006 Elsevier B.V. All rights reserved
Characterization of mechanically alloyed Fe100-xSix and Fe83.5Si13.5Nb3 nanocrystalline powders
, Article Journal of Materials Processing Technology ; Volume 203, Issue 1-3 , 2008 , Pages 554-560 ; 09240136 (ISSN) ; Abachi, P ; Madaah Hosseini, H. R ; Bahrami, A ; Sharif University of Technology
2008
Abstract
In present research, nanocrystalline Fe100-xSix (x = 6.5, 10, 13.5, 20 and 25 at.%) and Fe83.5Si13.5Nb3 alloy powders were prepared by mechanical alloying using high-energy ball milling. The resulting powders mainly consist of micron-sized particles with an average grain size of less than 20 nm. According to the XRD test results, by increasing the milling time and/or the Si content the lattice parameter decreases and the internal microstrain increases. In addition, the specific saturation magnetization diminishes as Si content increases. The coercive forces of the as-milled nanocrystalline powders are much higher than those of corresponding Fe-Si bulk alloys with a minimum at 13.5 at.% Si....
Effect of iron particle size on the diffusion bonding of Fe-5%Cu powder compact to wrought carbon steels
, Article Materials and Design ; Volume 29, Issue 2 , 2008 , Pages 411-417 ; 02613069 (ISSN) ; Simchi, A ; Kokabi, A. H ; Sharif University of Technology
Elsevier Ltd
2008
Abstract
In the present work, diffusion bonding of Fe-5%Cu powder compact to wrought carbon steels was studied. Effects of iron particle size and carbon content of the solid component on the bond strength, which is the maximum shear stress required to obtain separation at the interface, were investigated. Atomized iron powders with the mean particle size of 36, 56, 90, 106, and 148 μm and wrought steels with 0.22, 0.33, and 0.47 wt% carbon content were used. To evaluate the bonding zone, "ring shear" test, standard metallography technique, and micro-hardness test were employed. The results showed a profound effect of carbon content of the solid steel on the diffusion bonding process. It is suggested...
On the effect of cooling rate during melt spinning of FINEMET ribbons
, Article Nanoscale ; Volume 5, Issue 16 , 2013 , Pages 7520-7527 ; 20403364 (ISSN) ; Hosseini, H. R. M ; Davami, P ; Ostadhossein, F ; Song, M ; Gjoka, M ; Sharif University of Technology
2013
Abstract
The effect of quenching wheel speed on the structure and Curie temperature of Fe73.5Si13.5B9Nb3Cu1 alloy has been investigated using X-ray diffraction, differential scanning calorimetry, transition electron microscopy and a SQUID magnetometer. Ribbons were melt-spun at different wheel speeds and then were annealed to nucleate nano crystals embedded in the amorphous matrix. The results indicated that the thickness of the ribbons was inversely proportional to the wheel speed following the power law of the type t ∝ Vs -1.231. DSC and XRD results showed that at higher wheel speeds the greater potential energy triggers the formation of Fe (Si) crystallites and thus, increases the crystallinity....
Ab-Initio calculations of the CO adsorption and dissociation on substitutional Fe-Cu surface alloys relevant to Fischer-Tropsch Synthesis: Bcc-(Cu)Fe(100) and fcc-(Fe)Cu(100)
, Article Surface and Interface Analysis ; Volume 45, Issue 7 , 2013 , Pages 1081-1087 ; 01422421 (ISSN) ; Fazeli, E ; Joshani, A ; Gholami, M ; Sharif University of Technology
Abstract
Direct CO dissociation is seen the main path of the first step in the Fischer-Tropsch Synthesis (FTS) on the reactive iron surfaces. Cu/Fe alloy film is addressed with various applications over face-centered-cubic (fcc)-Cu and body-centered-cubic (bcc)-Fe in the FTS, i.e. preventing iron carbide formation (through direct CO dissociation) by moderating the surface reactivity and facilitating the reduction of iron surfaces, respectively. In this study by density functional theory, the stable configurations of CO molecule on various Cu/Fe alloys over fcc-Cu(100) and bcc-Fe(100) surfaces with different CO coverage (25% and 50%) have been evaluated. Our results showed that the ensemble effect...
Diffusion brazing of Ti–6Al–4V and AISI 304: an EBSD study and mechanical properties
, Article Journal of Materials Science ; Volume 52, Issue 20 , 2017 , Pages 12467-12475 ; 00222461 (ISSN) ; Shamanian, M ; Atapour, M ; Khosravi, B ; Sharif University of Technology
Abstract
Ti–6Al–4V and AISI 304 stainless steel were joined by diffusion brazing with a Cu interlayer at 900 °C for different bonding times. The influence of the bonding time on the joint width, microstructure, microhardness and shear strength was studied. Interfacial characterizations and the identification of phases were done by scanning electron microscopy and electron backscatter diffraction (EBSD). The results revealed that by increasing the bonding time, the thickness of the joint was first increased and then decreased. Microstructure examinations also showed that the joints consisted of several intermetallics such as TiCu, Ti2Cu, TiCu4, TiCu2, FeTi and Fe2Ti. On the other hand, EBSD results...
Effect of concurrent precipitation on the texture evolution during continuous heating of multi directionally forged solution treated Al-Cu-Mg alloy
, Article Materials Characterization ; Volume 131 , 2017 , Pages 399-405 ; 10445803 (ISSN) ; Kazeminezhad, M ; Logé, R ; Sharif University of Technology
Abstract
Concurrent precipitation in an age hardenable aluminum alloy determines recrystallization behavior especially grains structure and recrystallization texture during continuous heating. In this study, to investigate the effect of concurrent precipitation on the recrystallization texture and grains structure, a solution treated Al-Cu-Mg alloy has been multi-directionally forged at room temperature and continuously heated with different heating rates (800, 1600 and 2500 K·min− 1) up to 450 °C using Gleeble 3800 thermo-mechanical simulator. At lower heating rates (800 K·min− 1), Goss texture component {110} 〈001〉 (Φ1 = 90°/0°, Φ = 90°/45°, Φ2 = 45°/90°) is developed during continuous heating and...
Properties of Fe-Ni-Cr alloy coatings by using direct and pulse current electrodeposition
, Article Journal of Alloys and Compounds ; Volume 476, Issue 1-2 , 2009 , Pages 234-237 ; 09258388 (ISSN) ; Arshadi, M. R ; Sharif University of Technology
2009
Abstract
This paper describes the effects of using direct and pulse current on composition and corrosion resistance of Fe-Ni-Cr alloy coatings. In both direct and pulse current electrodeposition, increasing the current density has a decreasing effect on Fe and Ni and an increasing influence on Cr. In pulse current electrodeposition, duty cycle has a greater effect than frequency on composition of the alloy coating, particularly in the range of 10-50%. In this range, by increasing the duty cycle, Ni decreases, Fe sharply increase and Cr shows an increasing trend. Following a study of the microhardness of coatings, it is determined that the microhardness increases about 1.5 times by pulse current...
Atomistic investigation of the effects of symmetric tilt grain boundary structures on irradiation response of the α-Fe containing carbon in solution
, Article Computational Materials Science ; Volume 166 , 2019 , Pages 82-95 ; 09270256 (ISSN) ; Feghhi, S. A ; Samadfam, M ; Darvishzadeh, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this paper, molecular dynamics simulations were used to investigate the effect of the presence of carbon atoms, either in dispersed form or C-rich region, in low-carbon α-Fe containing symmetric tilt grain boundary (STGB)with a boundary plane rotated about the 110 misorientation axis on the number of SIAs and vacancies produced by PKA energies of 3, 5, 7 and 9 keV at 300 K. Results were compared with the SIAs and vacancies produced in pure α-Fe. It was also shown that the presence of GBs in this Fe-C alloy has no effect on the time at which point defects reach to their maximum values at the thermal spike stage. On the other hand, the GBs decrease the number of point defects in comparison...
Design, analysis, and fabrication of a direct drive permanent NdFeB magnet synchronous motor for precision position control
, Article IET Electric Power Applications ; Volume 14, Issue 8 , 2020 , Pages 1438-1445 ; Damaki Aliabad, A. A ; Ghafarzadeh, M ; Shamlou, S ; Sharif University of Technology
Institution of Engineering and Technology
2020
Abstract
Direct drive motors have the excellent ability for precision position control due to their direct connection to load and elimination of the gearbox and pulley backlash. Among the direct drive motors, permanent NdFeB magnet synchronous motors (PMSMs) are the best choice for control systems due to their high efficiency, high power density, good dynamic behaviour, and excellent controllability. This study deals with the design, analysis, and fabrication of a direct drive PMSM for precision position control. To reach this aim, the designed motor should have very low cogging torque and torque ripple to avoid the motor deviation at the target point. To achieve these purposes, at first, a suitable...
Processing of Al-20Si-5Fe-2X(X=Cu, Ni, Cr) alloys by melt-spinning and hot-pressing
, Article European International Powder Metallurgy Congress and Exhibition, Euro PM 2008, Mannheim, 29 September 2008 through 1 October 2008 ; Volume 2 , 2008 , Pages 99-104 ; 9781899072033 (ISBN) ; Simchi, A ; Davami, P ; Sharif University of Technology
European Powder Metallurgy Association (EPMA)
2008
Abstract
Al-20Si-5Fe-2X (X=Cu, Ni, Cr) ribbons were produced by melt-spinning and consolidated by hot pressing at 400°C for 60 min. Optical and transmission electron microscopy (TEM), X-ray diffractometry (XRD), and hardness test were used to evaluate the microstructure and mechanical strength of the ribbons and hot consolidated specimens. The compressive strength of the specimens at ambient and elevated temperatures was also examined. The microstructure of the ribbons exhibited featureless and dendritic zones, and contains spherically-shaped Si particles with an average diameter of 20 nm. After hot-pressing, ultrafine Si (110-150 nm) and iron-containing intermetallic particles were formed. The...
Efficient electrocatalytic oxidation of water and glucose on dendritic-shaped multicomponent transition metals/spongy graphene composites
, Article Electrochimica Acta ; Volume 386 , 2021 ; 00134686 (ISSN) ; Mohammadi, R ; Mojaddami, M ; Rahmati, R ; Hemmati, A ; Simchi, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
To improve the efficiency of electrochemical processes for environmental remediation, we present a new type of hybrid nanomaterials based on leaf-like copper-based quaternary transition metals and spongy monolayer graphene. To demonstrate the functionality of the hybrid electrocatalyst, fast and competent electrooxidation of water and glucose is shown. The mechanism of improved catalysis is ascribed to the synergetic catalytic effect of quaternary Cu-Ni-Fe-Co alloy with dendritic morphology along with the highly conductive and spongy structure of the graphene monolayer. It is shown that water oxidation can be performed at a low overpotential of 315 mV to reach a current denisty of 100 mA...
Preparation of nanocrystalline Fe-Si-Ni soft magnetic powders by mechanical alloying
, Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 123, Issue 1 , 2005 , Pages 74-79 ; 09215107 (ISSN) ; Bahrami, A ; Sharif University of Technology
2005
Abstract
In this study, structural and magnetic properties of nanocrystalline Fe-Si-Ni powders produced by mechanical alloying (MA) have been investigated. The samples with different chemical compositions and milling times were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The alloy powders with average grain size 8-19 nm were synthesized by milling for 35-100 h. Coercivity (Hc) and crystallite size exhibited a similar decrease by increasing the mechanical alloying time. Maximum saturation magnetization (Ms) and minimum Hc were obtained at the composition of Fe87Si10Ni5 after 70 h milling. © 2005 Elsevier B.V. All rights reserved
Efficient electrocatalytic overall water splitting on a copper-rich alloy: an electrochemical study
, Article Energy and Fuels ; Volume 36, Issue 8 , 2022 , Pages 4502-4509 ; 08870624 (ISSN) ; Mojaddami, M ; Zamani Faradonbeh, Z ; Zekiy, A. O ; Simchi, A ; Sharif University of Technology
American Chemical Society
2022
Abstract
The development of active, durable, cost-effective, and stable electrocatalysts is an urgent need for various industrial fields including renewable energy systems. The state-of-the-art catalysts suffer from poor water splitting activity in alkaline media due to their sluggish kinetics, high cost, and scarcity on earth to be scaled up. Herein, we present an electrochemical analysis of a nanostructured electrocatalyst based on a face-centered cubic (FCC) copper-rich Cu-Ni-Fe-Cr-Co alloy with a quasi-spherical morphology electrodeposited on a highly porous nickel substrate. Electrochemical studies determine the enhanced electrocatalytic activity toward both hydrogen and oxygen reactions in an...
Investigation the structural and magnetic properties of FINEMET type alloy produced by mechanical alloying
, Article Advanced Materials Research ; Vol. 970, issue , 2014 , p. 252-255 ; Siyani, S. M ; Hosseini, H. R. M ; Davami, P ; Sharif University of Technology
Abstract
In this research, FINEMET alloy with composition of Fe73.5Si13.5B9Nb3Cu1 was produced by mechanical alloying from elemental powders. The effect of milling time on the magnetic and structural properties of alloy has been investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometery. The results showed that milling for 53 hr leads to the formation of Fe supersaturated solid solution which includes Si, B and Nb atoms with mean crystallite size of ~30 nm. The shift of the main peak of Fe to the higher angles indicated that Si and B atoms dissolve in the Fe solid solution, at primary stage of mechanical alloying, up to the...
Impact-abrasion wear characteristics of in-situ VC-reinforced austenitic steel matrix composite
, Article Materials Science and Engineering A ; Volume 585 , 2013 , Pages 422-429 ; 09215093 (ISSN) ; Karimzadeh, N ; Varahram, N ; Davami, P ; Sharif University of Technology
2013
Abstract
In this investigation, in-situ precipitation of vanadium carbides was employed to reinforce Fe-13Mn and Fe-13Mn-3W alloys by means of conventional melting and casting route. Microstructures were characterized by optical and scanning electron microscopy techniques.Mechanical properties of the materials were determined by hardness, impact toughness and tension tests. It was observed that tungsten improved the strength of the matrix and the reinforcements as well as tensile properties and work hardening rate of the VC-reinforced composite. Ball mill abrasion test was utilized to simulate impact-abrasion wear condition using two types of abrasive minerals. The results showed that the degree of...
On the effect of hydrogen and Fe on reproducibility of tensile properties in cast Al-Si-Mg alloys
, Article Materials Science and Engineering A ; Volume 565 , 2013 , Pages 278-284 ; 09215093 (ISSN) ; Davami, P ; Varahram, N ; Kim, S. K ; Sharif University of Technology
2013
Abstract
Gas porosities and Fe-rich phases and entrapped double oxide films (hereafter: oxides) are known to be the most detrimental defects in cast Al-Si-Mg alloys. The effects of H (gas porosities) and Fe (Β-Al5FeSi phase) on reproducibility of tensile properties in Al-7Si-0.35Mg alloy have been investigated in this study. Four different casting conditions (Low H-Low Fe, Low H-High Fe, High H-Low Fe and High H-High Fe) were studied. In each case, 30 tensile test samples were prepared by casting in a metallic mold and machining (total of 120 tensile test samples). Results of tensile test were analyzed by Weibull three-parameter analyses. The microstructures of samples were studied by optical...
Effect of oxide films, inclusions and Fe on reproducibility of tensile properties in cast Al-Si-Mg alloys: Statistical and image analysis
, Article Materials Science and Engineering A ; Volume 558 , 2012 , Pages 134-143 ; 09215093 (ISSN) ; Davami, P ; Kim, S. K ; Varahram, N ; Yoon, Y. O ; Yeom, G. Y ; Sharif University of Technology
2012
Abstract
Double oxide films (hereafter: oxides), inclusions and Fe-rich phases are known to be the most detrimental defects in cast Al-Si-Mg alloys. The effects of these defects on reproducibility of tensile properties in Al-7Si-0.35Mg alloy have been investigated in this study. Four different casting conditions (low oxide-low Fe, high oxide-low Fe, low oxide-high Fe and high oxide-high Fe) were studied. In each case, 30 tensile test samples were prepared by casting in a metallic mold and machining (total of 120 tensile test samples). Results of tensile test were analyzed by Weibull three-parameter and mixture analyses. The microstructure and fracture surface of samples were studied by optical and...
The effects of pulse plating variables on morphology and corrosion behavior of Zn-Fe alloy coatings
, Article Journal of Coatings Technology Research ; Volume 9, Issue 2 , 2012 , Pages 215-218 ; 15470091 (ISSN) ; Heydarzadeh Sohi, M ; Sharif University of Technology
2012
Abstract
Considerable researches have been focused on zinc-iron (Zn-Fe) alloy coatings due to their superior characteristics among zinc alloy electrodeposits in recent years. The corrosion behavior of these coatings depends on the phase structure and morphology of the Zn-Fe deposits. In this work the effects of pulse plating variables such as current density, off-time, frequency and pulse modes on the morphology and phase structure of Zn-Fe deposits was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS) analysis. The corrosion behavior of these coatings was measured by means of polarization curves and Neutral salt spray tests. It was shown...
The effect of Mn addition on the microstructure and mechanical properties of gas-atomized Al-20Si-5Fe-3Cu-1Mg powder
, Article Advanced Materials Research, 15 December 2011 through 18 December 2011 ; Volume 410 , 2012 , Pages 253-256 ; 10226680 (ISSN) ; 9783037853160 (ISBN) ; Rajabi, M ; Davami, P ; Sharif University of Technology
2012
Abstract
In this study, Al-20Si-5Fe-3Cu-1Mg-XMn (X=0,1.5,3) alloys were synthesized by the gas atomizing technique. The microstructure and mechanical properties of the powders were investigated using optical microscopy, scanning electron microscopy, X-ray diffractometery method, and microhardness test. Microstructure of the powders composed of α-Al, Si and iron intermetallic compounds. As the powder particle size decreases, the phases become finer. A significant refinement in the size of iron-containing compounds was observed by addition of Mn. The microstructural refinement by controlling the particle size leads to an increase in the hardness of the powder particles in the amount of 33-45% dependent...