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magnesium
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Investigating Microstructure, Mechanical Properties and Corrosion Resistance of New Biodegradable Mg-2Zn-xAg-yCu (x=0-0.6,y=0-0.1) Alloys
, M.Sc. Thesis Sharif University of Technology ; Alizadeh, Reza (Supervisor) ; Sadrnezhaad, Khatiboleslam (Co-Supervisor)
Abstract
Magnesium has recently been considered as a biocompatible metal with mechanical properties close to bone for use in biological applications. On the other hand, the degradation properties of this metal in the physiological environment have made this metal superior to permanent biomaterials such as stainless steel, titanium alloys. The most important challenge of using this alkaline earth metal in the body environment is its rapid corrosion, which causes problems such as alkaline toxicity and loss of supporting role before complete tissue repair. In this study, Mg-Zn-Ag-Cu alloys were manufactured to improve mechanical strength, corrosion resistance and antibacterial properties. Finally, after...
Process optimization for mineral carbonation in aqueous phase
, Article International Journal of Mineral Processing ; Vol. 130 , July , 2014 , pp. 20-27 ; ISSN: 03017516 ; Shayegan, J ; Bu, J ; Yeo, T. Y ; Sharratt, P ; Sharif University of Technology
Abstract
Carbon dioxide sequestration by a pH-swing carbonation process was considered in this work. A multi-step aqueous process is described for the fractional precipitation of magnesium carbonate and other minerals in an aqueous system at room temperature and atmospheric pressure. With the aim to achieve higher purity and deliver more valuable mineral products, the process was split into four steps. The first step consists of Mg leaching from the magnesium silicate in a stirred vessel using 1 M HCl at 80 °C, followed by a three step precipitation in reactors in sequence to remove Fe(OH)3, then Fe(OH)2 and other divalent ions, and finally MgCO3 nucleation and growth. Hydrated magnesium carbonate...
Structure and corrosion behavior of oxide layer with Zr compounds on AZ31 Mg alloy processed by two-step plasma electrolytic oxidation
, Article Surface and Coatings Technology ; Vol. 238 , 2014 , pp. 75-79 ; ISSN: 02578972 ; Lee, K. M ; Sani, M. A. F ; Yoo, B ; Shin, D. H ; Sharif University of Technology
Abstract
The formation of the oxide layer with Zr compounds on AZ31 Mg alloy processed by two-step plasma electrolytic oxidation (PEO) has been investigated. After the PEO process first in an alkaline phosphate electrolyte and second in an acid electrolyte containing K2ZrF6, the microstructure, chemical composition, and phase composition of the oxide layers were analyzed via SEM, EDS, and XRD, respectively. The electrochemical reaction and the high temperature caused by the plasma discharges in the electrolyte were the main factors leading to the fabrication of an oxide layer containing Zr compounds on AZ31 Mg alloy. The micro-pores were filled with ZrO2 formed during the PEO process. The results of...
A new energy-based isothermal and thermo-mechanical fatigue lifetime prediction model for aluminium-silicon-magnesium alloy
, Article Fatigue and Fracture of Engineering Materials and Structures ; Volume 36, Issue 12 , 2013 , Pages 1323-1335 ; 8756758X (ISSN) ; Azadi, M ; Winter, G ; Eichlseder, W ; Sharif University of Technology
2013
Abstract
In this paper, a new fatigue lifetime prediction model is presented for the aluminium-silicon-magnesium alloy, A356.0. This model is based on the plastic strain energy density per cycle including two correction factors in order to consider the effect of the mean stress and the maximum temperature. The thermal term considers creep and oxidation damages in A356.0 alloy. To calibrate the model, isothermal fatigue and out-of-phase thermo-mechanical fatigue (TMF) tests were conducted on the A356.0 alloy. Results showed an improvement in predicting fatigue lifetimes by the present model in comparison with classical theories and also the plastic strain energy density (without any correction...
Hydrogen desorption properties of MgH2-5at% TiCr1.2Fe0.6 nanocomposite synthesized by high-energy mechanical alloying
, Article World Powder Metallurgy Congress and Exhibition, World PM 2010, Florence, 10 October 2010 through 14 October 2010 ; Volume 1 , 2010 ; 9781899072194 (ISBN) ; Simchi, A ; Kaflou, A ; Sharif University of Technology
European Powder Metallurgy Association (EPMA)
2010
Abstract
We have synthesized nanocrystalline MgH2-5at% TiCr1.2Fe0.6 nanocomposite powder by high-energy mechanical alloying for onboard hydrogen storage application. Magnesium hydride and the elemental Ti, Cr, and Ni powders were milled in a SPEX 800 mill under a high purity argon atmosphere. The dehydrogenation properties of the nanocomposite were studied by simultaneous thermal analyzer. The crystallite size of the nanocomposite was determined by XRD method. It is shown that nanometric grain structure, ultrafine particle size, and the catalytic effect of the transition metals possess a relatively low desorption temperature (262 °C) with 5.5wt % hydrogen release for the nanocomposite powder. The...
Low-temperature gas-solid carbonation of magnesia and magnesium hydroxide promoted by non-immersive contact with water
, Article RSC Advances ; Volume 6, Issue 92 , 2016 , Pages 89655-89664 ; 20462069 (ISSN) ; Chen, J ; Haghighatlari, M ; Åbacka, J ; Zevenhoven, R ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
From gas-solid carbonation studies and product characterization by XRD, carbon elemental analysis, and TG-FTIR profiling of evolved CO2, the presence of water vapour at high relative humidity (>25% RH) was shown to cause a drastic acceleration in the rate of CO2 absorption into MgO and Mg(OH)2 producing magnesite and hydrocarbonated precursors. From thermogravimetric experiments in the vicinity of the dew point, carbonation was shown to proceeded in steps triggered by spontaneous condensation (and re-evaporation) of water. Almost complete conversion to magnesite (MgCO3) and/or hydromagnesite [HM = 4MgCO3·Mg(OH)2·4H2O] was observed in a few hours under rather mild conditions of pressure (PCO2...
Investigation of ionic liquids based on pyridinium and imidazolium as interfacial tension reducer of crude Oil−water and their synergism with MgCl2
, Article Journal of Petroleum Science and Engineering ; Volume 171 , 2018 , Pages 414-421 ; 09204105 (ISSN) ; Ayatollahi, S ; Sharif University of Technology
Abstract
Ionic liquids (ILs) can be tailored as chemical surfactants and surface active agents to reduce the interfacial tension (IFT) of crude oil/aqueous solutions for enhanced oil recovery processes. The current investigation was aimed to explore the nature of ingenious active agents in crude oil, including asphaltene and resin, and their possible interactions with two families of ILs, namely pyridinium and imidazolium, on the IFT of crude oil/aqueous solutions, both in the presence and absence of MgCl2. To the best of our knowledge, the effect of crude oil type on the IFT of crude oil/aqueous solution containing salts and IL has not been ever investigated. Accordingly, IFTs of light, medium and...
Characterization of anisotropic behaviour of ZK60 extrusion under stress-control condition and notes on fatigue modeling
, Article International Journal of Fatigue ; Volume 127 , 2019 , Pages 101-109 ; 01421123 (ISSN) ; Behravesh, S. B ; Adibnazari, S ; Jahed, H ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
The anisotropic fatigue behavior of ZK60 is investigated through stress-control tests along two different material directions: extrusion (ED) and radial (RD) directions. The in-plane random texture along RD promotes activation of twinning/detwinning deformations in both tension and compression reversals, which brings about a sigmoidal but near-symmetric shape for hysteresis loops. The stress-strain response along ED is asymmetric, which is attributed to different deformation mechanisms in tension and compression reversals. The higher fatigue strength along ED is related to lower plastic strain energy in this direction. An energy damage parameter showed a good correlation with tests performed...
A comparative study between friction stir processing and friction stir vibration processing to develop magnesium surface nanocomposites
, Article International Journal of Minerals, Metallurgy and Materials ; Volume 27, Issue 8 , 2020 , Pages 1133-1146 ; Abbasi, M ; Abdollahzadeh, A ; Kokabi, A. H ; Sharif University of Technology
University of Science and Technology Beijing
2020
Abstract
Friction stir processing (FSP) can be used to improve surface composites. In this study, a modified method of FSP called friction stir vibration processing (FSVP) was applied to develop a surface composite on AZ91 magnesium alloy. In this technique, the workpiece is vibrated normal to the processing direction. The results illustrated that compared with the FSP method, the FSVP caused a better homogeneous distribution of SiC particles in the microstructure. The results also showed that matrix grains of friction stir vibration processed (FSV-processed) samples ((26.43 ± 2.00) µm) were finer than those of friction stir processed (FS-processed) specimens ((39.43 ± 2.00) µm). The results...
Effect of liquation on the tensile properties of cast Mg–9Al–1Zn Alloy fusion welds
, Article Science and Technology of Welding and Joining ; Volume 25, Issue 8 , 2020 , Pages 698-705 ; Jiryaei Sharahi, H ; Movahedi, M ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
This paper aims at understanding the role of liquation and solidification phenomena on the tensile properties of arc welded cast AZ91 magnesium alloy. Owing to its refined microstructure, the fusion zone exhibited improved ductility/strength compared to the base metal. It is demonstrated that the partially melted zone (PMZ) which is characterised by constitutional liquation of eutectic β-Mg17Al12 phase is the weakest link in the weldment. The reduced strength and ductility associated with the liquation phenomena are due to the increased volume fraction and thickness of the eutectic β-Mg17Al12 in the PMZ as well as the formation of liquation micro-cracks in a network of brittle intermetallic...
Microstructural evolution of AZ91 alloy containing 3%Ca prepared by cooling slope
, Article Semi-Solid Processing of Alloys and Composites 10 - Selected, peer reviewed papers from the 10th International Conference on Semi-Solid Processing of Alloy and Composites, S2P 2008, Aachen, 16 September 2008 through 18 September 2008 ; Volume 141-143 , 2008 , Pages 427-432 ; 10120394 (ISSN); 9771012039401 (ISBN) ; Aashuri, H ; Davami, P ; Narimannezhad, A ; Foroughi, A ; Kiani, M ; Sharif University of Technology
Trans Tech Publications Ltd
2008
Abstract
Globulization of the grain refined AZ91 magnesium alloy with Ca on a cooling slope was investigated. Dendritic morphology of the grains was transferred into round and well distributed small particles as a result of grain-refinement effect of Ca in the alloy. Semi-solid holding of the alloy was carried out at different temperatures to improve the spherecity of the globules. Results show that, remelting at 540 °C for 30 min provides the best shape factor for the alloy. The study of coarsening kinetic in this alloy showed lower growth rate alternative other research which used same condition for produce semi-solid billet just in using Ca
Wire-Based friction stir processing as a novel pathway for solid-state surface alloying of magnesium
, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 52, Issue 11 , 2021 , Pages 4737-4741 ; 10735623 (ISSN) ; Mousavizade, S. M ; Pouranvari, M ; Sharif University of Technology
Springer
2021
Abstract
Wire-based friction stir processing is introduced as a solid-state surface alloying strategy for surface alloying of AZ31 magnesium alloy with aluminum, as a key alloying element in magnesium alloys. This technique enables the formation of a defect-free, grain refined and alloyed surface with the increased volume fraction of Mg-Al second phase, and thus, enhanced surface hardness. This simple technique provides a solid-state surface alloying pathway to improve the surface properties of the metallic materials. © 2021, The Minerals, Metals & Materials Society and ASM International
Syngas production through CO2 reforming of propane over highly active and stable mesoporous NiO-MgO-SiO2 catalysts: Effect of calcination temperature
, Article Fuel ; Volume 322 , 2022 ; 00162361 (ISSN) ; Kazemeini, M ; Rezaei, M ; Farhadi, F ; Keshavarz, A. R ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this contribution, NiO-MgO-SiO2 catalyst was prepared and calcined at different temperatures of 500, 600, 700 and 800 °C. The resulting samples were characterized by BET-BJH, XRD, TPX, CO-chemisorption, EDS and SEM analyses. These were employed toward syngas production via propane dry reforming. The increment in the calcination temperature from 500 to 800 °C decreased the basicity of the catalysts. In addition, the active surface area and Ni dispersion were gradually declined by increasing the calcination temperature from 600 to 700 °C due to active metal sintering during the activation process. The calcined sample at 600 °C displayed the highest propane and CO2 conversions of 93% and 78%...
Synthesis mechanism and microstructure characterization of ZrB2–ZrC–SiC nanocomposite synthesized via magnesium boro/carbothermal reduction at low temperatures
, Article Materials Chemistry and Physics ; Volume 280 , 2022 ; 02540584 (ISSN) ; Bavand Vandchali, M ; Mashhadi, M ; Nemati, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this study, magnesium boro/carbothermal reduction of zirconium silicate (ZrSiO4) was employed to synthesize zirconium-based composite nanopowders of ZrB2–SiC, ZrB2–ZrC–SiC, ZrC–SiC, and ZrC. For this aim, three different temperatures of 1200 °C, 1300 °C, and 1450 °C were selected as the supposed temperatures for synthesis. Elemental Mg and NaCl were also selected to assist reduction process. In addition, effects of different C/Zr ratios as well as using elemental boron and B4C as two different boron sources were investigated on the final produced phases. Subsequently, XRD and SEM/EDS analyses were carried out to elaborate microstructure and phase studies. Finally, STA carried out up to...
An Investigation on Mechanical Properties of Mg-CNT Composites Produced using the Casting Process
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
Since the discovery of nanomaterials, the nanotubes have found special considerations. The high strength beside the low density, have attracted the interest of the scientists and engineers. Nowadays, one of the common methods to produce composites with high specific strength is to utilize of the nanotubes in the matrix of lightweight metals and alloys such as magnesium and aluminum. Recent researches indicate that very limited focus has been given to the production and properties of the magnesium - carbon nanotube composites and their workability. In this research, magnesium alloy - carbon nanotube composite is produced by casting method and its strength and workability are investigated as...
An Investigation into the Kinetics of Quench Aging in an Mg-Zn Alloy
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
Special features of magnesium such as low density, perfect bio-compatibility in the human body, and close elastic modulus to the human bone have increased the use of Mg alloys in the bio-medical applications. Nevertheless, low mechanical properties and poor corrosion resistance of Mg alloys have limited their bio-medical applications. The addition of alloying elements together with the use of precipitation hardening and plastic deformation are the most effective methods to improve the mechanical properties and increase the corrosion resistance of Mg alloys. Thus, the present research with the aim of improving the mechanical properties of an Mg-Zn alloy by Ca and Gd additions together with...
Sintering Improvement of Nano Hydroxyapatite Bodies by Magnesium Incorporation and Using Microwave Sintering
, M.Sc. Thesis Sharif University of Technology ; Sadrnejhad, Khatiboleslam (Supervisor) ; Behnam Ghader, Ali Asghar (Supervisor)
Abstract
Magnesium is one of most important elements in bio hedroxyapatite. Magnesium effects on all stages of bone growth metabolism. Also increases bone’s osteoblastic and osteoclastic activities. That’s why incorporation of Mg ions into hudroxyapatite structure has become one of interesting fields for bone implants production. In addition Mg can improve sintering and mechanical properties of HAp. Thet’s why in this investigation the effect of incorporated Mg into HAp structure has been studied. Three kinds of powders have been prepared to perform this study. Pure HAp nano powder produced via sol-gel method, Mg contain HAp nano powder produced via sol-gel method and a mixture of nano HAp and nano...
The Investigation on Hydroxyapatite Coating on Magnesium Alloy and Its Properties
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Magnesium and its alloys are biodegradable materials with mechanical properties similar to the bone tissue, therefore these materials are suitable for producing orthopedic implants. Unfortunately Magnesium and its alloys are corroded too fast in physiological environment which is the main obstacle for usage of these materials as orthopedic implants. Producing Hydroxyapatite(HA) coatings on surface of Magnesium and its alloys is one of the popular and useful methods for reducing the corrosion rate in physiological environment. HA is a biocompatible and bioactive coating with the ability to bond chemically with the bone tissue and therefore it is largely used as a bioactive coating on the...
Recovery of Pure Magnesium Oxide from Brine Sources
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor) ; Nosheh, Mohammad (Co-Advisor)
Abstract
Today a significant portion of the world magnesia supply is produced by approximately 20 manufacturers by precipitation of magnesium hydroxide either from seawater or brine sources, which amounts to about 14% of the world magnesia production. The first synthetic magnesia production occurred along the French coast of the Mediterranean Sea, near Aiques-Mortes, operating sometime before 1885. Magnesium hydroxide was precipitated from seawater by reacting it with milk of lime in a continuous fashion using three sequential agitated reactors. Because of the abundance of brine resources enrich in Magnesium in our country, in this project, was tried to precipitate Magnesium Hydroxide from brine...
Lithium Recovery from Brine Sources of Iran by Precipitation Method
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Lithium is one of the most commonly used metals in industry with a wide variety of applications including batteries, lubricating grease and pharmaceutical products. Demand for lithium is expected to rise with the increasing adoption of electric vehicles. Market reports have predicted that world lithium demand will increase by 2.5 times from 2010 to 2020. Therefore, there is a pressing need to develop new sources of lithium to support this anticipated increase in demand. Lithium can be extracted from salt brine and lithium containing minerals as lithium compounds.
Salt brines are the most abundant lithium sources available in the world, comprising about 60% of all known lithium deposits....
Salt brines are the most abundant lithium sources available in the world, comprising about 60% of all known lithium deposits....