Alireza Sadeghi

Alireza Sadeghi
University of Tehran | UT · School of Mechanical Engineering

Doctor of Philosophy

About

46
Publications
4,954
Reads
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503
Citations
Additional affiliations
January 2015 - present
University of Tehran
Position
  • Professor (Assistant)
January 2014 - February 2015
The University of Tokyo
Position
  • PostDoc Position
September 2008 - October 2012
McGill University
Position
  • PhD Student
Education
September 2008 - October 2012
McGill University
Field of study
  • Materials and Metallurgical Engineering
September 2006 - August 2008
Sharif University of Technology
Field of study
  • Materials Engineering
September 2001 - August 2006
Iran University of Science and Technology
Field of study
  • Materials Engineering

Publications

Publications (46)
Article
Mg17Al12 is the principal intermetallic second phase in the Mg–Al based alloys (AM series) that significantly affects their mechanical performance. Modification of this intermetallic has been possible with rare earth elements, resulting in mechanical performance improvement of the AM alloys. The modification of the intermetallic has been studied wi...
Article
A liquid metal corrosion (LMC) resistant and metallophobic lanthanum phosphate (LaPO4) coating was prepared on SUS316 stainless steel using electrophoretic deposition (EPD) technique. A specific hierarchical surface structure was created on coating surface by adjusting EPD process parameters. LMC test was performed using three different metal melts...
Article
In this work, a series of in-situ experiments were conducted to study the effect of grain size on fracture behavior of commercial-purity Mg polycrystalline aggregates. For this purpose, pure Mg rolled at 225 °C was annealed at 325 °C and 525 °C, each for 1 h, to acquire different grain structures. Micro specimens of the as-rolled and anneal-treated...
Article
Micro-arc oxidation (MAO) is one of the promising surface treatment methods that can enhance the corrosion resistance of magnesium alloys. However, the existence of pores and microcracks significantly restricts the further advancement of corrosion resistance. In this study, effective and environmentally friendly materials, layered double hydroxides...
Article
The present investigation explores the effect of Mg volume fraction (VMg) as a controlling parameter of absorption rate in designing patient-specific cardiovascular stents made of PLA + Mg composites. For the purpose of this research, PLA + Mg composite plates containing 1, 3, 5, and 10 % VMg are produced by melt blending and hot molding. Character...
Article
To enhance the corrosion resistance of an aluminum (Al) 6082 alloy, our research used electroless deposition to coat a trio sequence of Zn-Cu-Sn layers: zinc, copper and tin. To isolate the reactions and micro-mechanisms in the tin coating, the Zn-Cu layering parameters of time, temperature, and bath concentration were held constant while varying t...
Article
In this paper, a novel micro-tensile testing apparatus is designed and built to characterize the micromechanical behavior of materials. Furthermore, a special geometry for micro specimens is introduced that could facilitate problems related to the handling, gripping, and aligning such specimens. The device can be integrated with an optical microsco...
Article
Micro specimens of hot-rolled AZ31 and AZ31+0.8wt% Sr magnesium alloys were tensioned in the rolling direction, and fracture micro-mechanisms were studied by in-situ real-time optical observations, electron microscopy, and DIC analysis. In-situ observations indicated that strain localization on the microstructural shear bands developed during tensi...
Article
Full-text available
The bonding strength, and microstructures of Cu and Al couples using metallic powders as interlayer during transient liquid phase bonding (TLP bonding) were investigated. The interfacial morphologies and microstructures were studied by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, and X-ray diffraction. First, to...
Article
This paper studies high-temperature creep deformation of Mg retort tubes considering the decarburisation of steel. A material model was developed for finite element modelling that relates the activation energy of steel in the steady-state creep rate equation (Q) to its carbon content. Carbon content was described as a function of radial position al...
Article
Magnetic pumps received considerable attention because of their very low turbulence and their independence from moving components. Such pumps have a higher lifetime and lower maintenance costs compared to mechanical pumps. In the past centuries, it developed many types of fluid pumps for different fields of application. In the industry of magnesium...
Article
We report the influence of strontium on the evolution of microstructural damage during tensile deformation of hot-rolled AZ31 alloys tested parallel to the rolling, transverse, and diagonal directions using a 4D (3D X-ray tomography plus time) technique. X-ray computed tomography images were collected at several strains during each tensile test, an...
Article
Magnesium reduction retorts fail after 60 days of operation owing to the extreme operating conditions (1200°C and internal vacuum). Understanding failure micro-mechanisms is vital to designing new retorts with a prolonged lifespan. In this study, detailed thermodynamic simulation and microstructural examination are presented for creep failure analy...
Article
Reduction steel retorts are extensively used in the production of magnesium by the Pidgeon process. As the equipment is subjected to elevated temperatures, it expires within two months as a consequence of excessive creep deformation. This study was conducted to prolong the life of retorts and reduce Mg production costs through the application of su...
Article
Thermal reduction of Mg from calcined dolomite takes place in heat resistant steel thick-walled retort tubes at 1200°C under internal vacuum. Retorts are failed within approximately two months owing to the operating condition. Two primary mechanisms are involved in premature failure of magnesium reduction steel retorts: creep deformation and high-t...
Article
Full-text available
Large strain extrusion machining (LSEM) is used to produce pure magnesium strips directly from as-cast billets. LSEM reduces manufacturing steps and the special shear direction inclines the unfavorable strong basal texture of Mg. Finding suitable parameter ranges to control geometry and properties of the produced strip is a great challenge. In the...
Article
Metallic magnesium is produced through a reduction reaction inside thick-walled tubes called retorts. Retorts operate at 1200 °C with an internal vacuum that causes high temperature creep deformation and short lifespan. This paper predicts retort creep deformation via three-dimensional (3D) finite element simulation using creep model constants obta...
Article
Size and shape tailored stoichiometric lanthanum phosphate (LaPO4) nanoparticles were synthesized through an aqueous sol-gel technique. The effect of reactant concentration on the shape and size of nanoparticles was investigated. Shape evolution of nanoparticles was explained by the spherical diffusion growth mechanism. It was observed that by redu...
Article
Full-text available
The influences of Sr on the microstructure, texture and mechanical properties including flow and anisotropy behavior of AZ31 alloys are investigated. Slabs containing no, 0.4 and 0.8 wt% of strontium were cast and subjected to hot rolling. Results indicate that Sr reduces the basal texture intensity (23% in the AZ31+0.8Sr alloy) and homogenizes the...
Article
To join AM60 to SS304 a 1 μm layer of Zn was deposited on the Mg alloy side by sputtering. Through the TLP process, eutectic constituents of MgZn and Mg7Zn3 are solidified at the interface as the main intermetallics. Based on Mg concentration in different locations of the interface, either primary Mg or MgZn crystallize before the eutectic reaction...
Article
To join AM60 to SS304 a 1 μm layer of Zn was deposited on the Mg alloy side by sputtering. Through the TLP process, eutectic constituents of MgZn and Mg7Zn3 are solidified at the interface as the main intermetallics. Based on Mg concentration in different locations of the interface, either primary Mg or MgZn crystallize before the eutectic reaction...
Article
Reduction retort operational life is a crucial factor in the production cost and final price of magnesium. Retorts fail by creep through exposure to high temperature and vacuum. In this study, creep tests were performed at various temperatures and stress levels to establish an appropriate material model for predicting vacancy diffusion creep at ele...
Article
The effect of Sr addition on corrosion behaviour of AZ31 was investigated. The corrosion properties were characterized by immersion, electrochemical, scanning Kelvin probe microscopy and microstructural experiments. With increasing Sr concentration, the Vf of Al-Sr precipitates increases. Furthermore, SKPFM results show that Al-Sr and Al-Mn precipi...
Article
Thermomechanical simulation is used to predict material flow and residual stresses in joining duplex stainless steel (DSS) to a Cu-alloy by friction stir welding (FSW). The coupled Eulerian-Lagrangian (CEL) method was applied for modeling large deformation. Welding experiments are used to verify simulation results. Results indicate that DSS initial...
Article
In the present study, different combinations of multilayer sheets were prepared from 1 and 2 mm Mg AZ31 along with 0.25, 0.5, and 1 mm 304 L stainless steel. The texture and microstructure of the elongated samples (20 and 30 pct strain) were studied. It was found that the transversal stress plays an important role in both texture evolution and twin...
Article
Laminated metallic composites consisting of an AZ31 magnesium alloy layer and two SS304 austenitic stainless steel layers were fabricated by a reactive transient liquid phase bonding method to achieve a metallic composite exhibiting an exceptional combination of specific strength and ductility. Three different initial microstructures were selected...
Article
Dissimilar joining of copper to duplex stainless steel (DSS) is challenging at high temperatures of fusion welding owing to the large difference in physical properties of the base metals. To reduce negative effects of welding at high temperatures, solid state welding at lower temperatures has been proposed. To study different effects of welding par...
Article
Different multilayer Mg AZ31 and SS304L steel sheet combinations were prepared with different volume fractions of Mg. Isolated stress–strain curves of the Mg layers showed significant improvements in the strength and elongation of multilayer samples. Results indicated that in the most extreme situation with the lowest Mg volume fraction (Vf = 0.39)...
Article
The deformation modes of Mg in a steel-Mg-steel multilayer composite were studied by step-by-step deformation and EBSD for the same region at 0, 20 and 30% deformation. Texture evolution was characterized using pole figures. The results indicate that the basal texture intensity significantly increases up to 20% deformation. However, from 20% to 30%...
Conference Paper
Full-text available
Mg/Stainless steel laminated metallic composites (LMC) have been prepared using 1mm Mg AZ31 rolled sheet and 304 stainless steel layers with different thicknesses using liquid transient liquid phase bonding. Samples with different volume fractions of Mg and SS were strained to different levels up to 40%. Twining behavior has been evaluated using EB...
Conference Paper
Full-text available
AZ31 magnesium alloys with 0.05, 0.4 and 0.8 weight percent Sr were cast and hot extruded at 250C and 350C. It has been found that trace amounts of Sr (0.05wt%), reduces the grain size and increase the texture intensity of hot extruded samples. In contrast, high concentrations of Sr (0.4% and 0.8wt%) increase the grain size, slightly reduce the tex...
Article
Full-text available
Seamless tubes of AZ31, AZ31 + 0.4, and 0.8 wt pctSr were extruded at elevated temperatures. By compressing pure copper inserts inside the tubes, the extruded tubes were expanded at room and elevated temperatures [373 K and 473 K (100 °C and 200 °C)]. Microstructural examinations reveal the formation of twining in the as-extruded and expanded tubes...
Article
Full-text available
The objective of this article is to quantify relationships between microstructural changes and the room temperature mechanical behavior of novel extruded Mg–Al–Zn–Sr alloys. To this aim, targeted mechanical testing coupled with full-field strain measurements and simultaneous acoustic emission recordings is further combined with grain-scale observat...
Article
The effect of pre-deformation annealing on the microstructure and texture of an AZ31 + 0.74 wt% Sr alloy has been investigated. As-cast samples as well as three samples that have been annealed at 400 A degrees C for 10, 30, and 120 min were extruded at 300 A degrees C. Results indicate that annealing transforms the bulky non-equilibrium Al-Mg-Sr pr...
Article
Three Mg alloys (AZ31, and AZ31 + 0.4 and 0.8 wt%Sr) were successfully hot extruded into tubes at 400 °C through a porthole die. Strontium (Sr) additions to AZ31 alloy reduced twining and the dynamically recrystallized grain size. However, Sr also increased the surface cracking tendency during extrusion. It was noted that the complex deformation pa...
Article
Tensile and compression experiments were carried on Mg–3Al–1Zn alloys containing different levels of Sr (0.05, 0.4 and 0.8wt%) extruded at elevated temperatures of 250, 300, 350 and 400°C and the results were compared to AZ31 alloy. The addition of 0.05wt%Sr to the alloy produces the highest strength and the alloy containing 0.4wt%Sr has the highes...
Article
The effect of low levels of Sr (0.01, 0.03, 0.05 wt.%) on the microstructure, mechanical properties and texture of AZ31 magnesium alloy has been investigated. Thermodynamic modeling has been used to study the effect of Sr on phase precipitation at different temperatures. Cooling curve analysis reveals a decrease in solidification superheat with the...
Article
Microstructural investigation and thermodynamic simulation were carried out to study precipitation during the solidification of AZ31 Mg alloy containing up to 1wt% Sr. Increasing Sr content from 0.01 to 1 wt% led to the formation of an Al–Sr line compound (Al4Sr) and to the suppression of Al–Mg precipitate (β-Mg17Al12). Transmission electron micros...
Article
An experimental investigation of texture evolution during the elevated temperature extrusion of AZ31 alloys containing strontium (Sr) additions is reported. The crystallographic texture of hot extruded alloys containing different levels of Sr has been examined. Hot compression tests have been carried out in order to investigate the hot deformation...
Article
Microstructure and texture evolution during the extrusion of AZ31 magnesium alloy containing 0.4 and 0.8 wt%Sr has been investigated. Following extrusion at 250 degrees C, the microstructure consists of fine recrystallized and large elongated grains along with Al4Sr stringer precipitates. Extrusion at 350 degrees C results in larger and more unifor...
Article
Accumulative roll bonding (ARB) is one of the effective severe plastic deformation methods for developing very fine grained nanostructures. In the present work, grain refinement and microstructural changes of magnesium AZ31 alloy during ARB process was investigated. Sheet specimens up to 256 cold welded layers (eight ARB cycles) were prepared. Evol...

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Projects (2)
Project
Dissimilar metals joining is one of the most common discussion topics in welding. In this project, two of the metals with the most consumption in the world is tried to join. Because of the difference between Aluminium and Steel melting point, these two metals can not be welded together by conventional methods. Transient Liquid Phase Bonding is one of the solid-state methods that is not engaging with the melt at all. In this study, mechanical behaviors and microstructural properties are going to be investigated.