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Fabrication of Bulk (Fe,Cr)_3Al/Al_2O_3 Intermetallic Matrix Nanocomposite Through Mechanical Alloying and Sintering

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Acta Metallurgica Sinica(English Letters) 2016年第10期29卷 911-919页

作者： Sayyed Erfan Aghili mohammad hossein Enayati Fathallah Karimzadeh Department of Materials Engineering Isfahan University of Technology

In the present study, （Fe,Cr）3Al/20 vol% A1203 nanocomposite was prepared through mechanochemical reactions during ball milling and successfully bulked using a combination of cold isostatic press and sintering at 1400℃ for 1 h. Two processing approaches were utilized to produce （Fe,Cr）3A1/A1203 nanocomposite： The first was milling of Fe, Cr, AI and Fe203, while the second one was milling of Fe, Cr, Al and Cr203, both in stoichiometric condition, to synthesize （Fe,Cr）3Al/20 vol% Al2O3. Structural changes of powder particles during mechanical alloying were studied by X-ray diffraction. The microstructure and the morphology of powder particles and bulk samples were also studied by scanning electron microscopy and transmission electron microscopy. Microstructural analysis showed that mechanochemical reactions took place during milling, and nanometric Al2O3 was uniformly distributed in the matrix. The results also showed that the second approach required a considerably higher milling time to produce （Fe,Cr）3Al/Al2O3 nanocomposite, as compared to the first one. For this reason, bulk samples were produced from the synthesized nanocomposite in the first approach. The microstructure of the sintered samples consisted of a network structure of （Fe,Cr）3Al and Al2O3 phases with superior mechanical properties.

关键词： Iron aluminide Mechanical alloying Nanocomposite Mechanochemical treatment

Influence of Specimen Geometry of Hot Torsion Test on Temperature Distribution During Reheating Treatment of API-X70

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Journal of Iron and Steel Research International 2010年第3期17卷 34-39页

作者： Bahman Mirzakhani Shahin Khoddam hossein Arabi mohammad Taghi Salehi Seyed hossein Seyedein mohammad Reza Aboutalebi Faculty of Engineering Arak University Department of Mechanical Engineering Monash UniversityClayton Campus Department of Materials and Metallurgical Engineering Iran University of Science and Technology

The commercial finite element package ANSYSTM was utilized for prediction of temperature distribution during reheating treatment of hot torsion test （HTT） samples with different geometries for API-X70 microalloyed steel. Simulation results show that an inappropriate choice of test specimen geometry and reheating conditions before deformation could lead to non-uniform temperature distribution within the gauge section of specimen. Therefore, assumptions of isothermal experimental conditions and zero temperature gradient within the specimen cross section appear unjustified and led to uncertainties of flow curve obtained. Recommendations on finding proper specimen geometry for reducing temperature gradient along the gauge part of specimen will be given to create homogeneous initial microstructure as much as possible before deformation in order to avoid uncertainty in consequent results of HTT.

关键词： hot torsion test simulation specimen geometry reheating treatment microalloyed steel

Corrosion Behavior and Biocompatibility of Hydroxyapatite Coating on H_2SO_4 Passivated 316L SS for Human Body Implant

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Acta Metallurgica Sinica(English Letters) 2013年第4期26卷 409-415页

作者： Ali Parsapour Saied Nouri Khorasani mohammad hossein Fathi Biomaterials Research Center Department of Chemical Engineering Isfahan University of Technology Department of Materials Engineering Isfahan University of Technology

The aim of this studies at simultaneous improvement of the corrosion behavior and biocompatibility of metallic implant and bone Osseointegration simultaneously. Stainless steel 316L （SS） was used as metallic substrate and after surface treatment with 15 vol.% sulfuric acid, it was coated with hydroxyapatite coating employing plasma - spraying process. Structure characterization techniques including XRD, SEM and EDX were also utilized to investigate the microstructure, morphology, and crystallinity of the coating. Electrochemical potentiodynamic tests were performed in two types of physiological solutions in order to determine and compare the corrosion resistance behavior of the coated and uncoated specimens as an indication of biocompatibility. The results indicate that the surface treatment and hydroxyapatite coating improve the corrosion resistance behavior of SS. The corrosion current density of the surface treated and the hydroxyapatite coated SS also decrease. These also show that surface treated and hydroxyapatite coated SS can be used as human body implants with the goals of corrosion resistance improvement （biocompatibility） and bone osseointegration.

关键词： Surface treatment Hydroxyapatite coating Corrosion behavior Plasma spray Stainless steel 316L Human body implant

Effect of Surface Treatment and Metallic Coating on Corrosion Behavior and Biocompatibility of Surgical 316L Stainless Steel Implant

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Journal of Materials Science & Technology 2012年第2期28卷 125-131页

作者： Ali Parsapour Saied Nouri Khorasani mohammad hossein Fathi Department of Materials Engineering Isfahan University of Technology Department of Chemical Engineering Isfahan University of Technology

Surface engineering technology is a suitable method for coatings on the metal surfaces or performing surface modification treatment, which can improve corrosion resistance and biocompatibility of metals. In this research, corrosion behavior of Nb coating on H2SO4 and HNO3 treated AISI stainless steel 316L （SS） was evaluated. Nb coating was carried out using physical vapor deposition process on the SS. Characterization techniques including scanning electron microscopy （SEM） and energy dispersive X-ray （EDX） technique were used to investigate the microstructure and morphology of the coated and treated SS. Electrochemical potentiodynamic tests were performed in two types of physiological solutions and compared with the pristine SS specimens. Cyclic polarization tests were performed to evaluate resistivity against pitting. Experimental results indicate that Nb coating and surface treatment of the SS had a positive effect on improvement of corrosion behavior. The decrease in corrosion current densities was significant for coated and treated specimens. The corrosion current density was much lower than the values obtained for pristine specimens.

关键词： 316L stainless steel Corrosion behavior Nb coating Surface treatment

Efficient one-pot synthesis of 1,3-diaryl-3H-benzo[f]chromenes using ferric hydrogensulfate

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Chinese Chemical Letters 2010年第12期21卷 1423-1426页

作者： hossein Eshghi Gholam hossein Zohuri Saman Damavandi mohammad Vakili Department of Chemistry School of SciencesFerdowsi University of MashhadMashhad 91775-1436Iran School of Chemistry Damghan University of Basic SciencesP.O.Box 36715-364DamghanIran

An efficient and easy method for one-pot three-component synthesis of l,3-disubstituted-3H-benzo[f]chromenes by the condensation of naphtol,aromatic aldehyde derivatives and phenylacetylene in the presence of ferric hydrogensulfate[Fe（HSO4）3], has been *** catalyst displayed high activity which afforded the corresponding 1,3-disubstituted-3H-benzo[f]chromenes in satisfying ***-substituted phenols were examined and the corresponding benzopyran derivatives were synthesized in moderate *** nature of the using catalyst made it reusable for further chemical reactions.

关键词： 1,3-Disubstituted-3H-benzo[f]chromenes Ferric hydrogensulfate One-pot synthesis Naphtopyran Benzopyran

A Comprehensive Overview on the Latest Progress in the Additive Manufacturing of Metal Matrix Composites: Potential, Challenges, and Feasible Solutions

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Acta Metallurgica Sinica(English Letters) 2021年第9期34卷 1173-1200页

作者： Mehran Dadkhah mohammad hossein Mosallanejad Luca Iuliano Abdollah Saboori Department of Applied Science and Technology Politecnico di TorinoCorso Duca Degli Abruzzi 2410129 TorinoItaly Department of Materials Engineering Isfahan University of Technology84156-83111 IsfahanIran Department of Management and Production Engineering Politecnico di TorinoCorso Duca Degli Abruzzi 2410129 TorinoItaly

Nowadays, as an emerging technology, additive manufacturing(AM) has received numerous attentions from researchers around the world. The method comprises layer-by-layer manufacturing of products according to the 3D CAD models of the objects. Among other things, AM is capable of producing metal matrix composites(MMCs). Hence, plenty of works in the literature are dedicated to developing different types of MMCs through AM processes. Hence, this paper provides a comprehensive overview on the latest research that has been carried out on the development of the powder-based AM manufactured MMCs from a scientific and technological viewpoint, aimed at highlighting the opportunities and challenges of this innovative manufacturing process. For instance, it is documented that AM is not only able to resolve the reinforcement/matrix bonding issues usually faced with during conventional manufacturing of MMCs, but also it is capable of producing functionally graded composites and geometrically complex objects. Furthermore, it provides the opportunity for a uniform distribution of the reinforcing phase in the metallic matrix and is able to produce composites using refractory metals thanks to the local heat source employed in the method. Despite the aforementioned advantages, there are still some challenges needing more attention from the researchers. Rapid cooling nature of the process, significantly different coe fficient of expansion of the matrix and reinforcement, processability, and the lack of suitable parameters and standards for the production of defect-free AM MMCs seem to be among the most important issues to deal with in future works.

关键词： Additive manufacturing Metal matrix composite Microstructure Interfacial bonding Mechanical properties

Bedload resistance in supercritical flow

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International Journal of Sediment Research 2009年第4期24卷 400-409页

作者： Alireza HABIBZADEH mohammad hossein OMID Dept.of Irrigation and Reclamation Eng. University of Tehran Dept. of Irrigation and Reclamation Eng. University of Tehran

The movement of bedload in subcritical flow produces additional roughness as compared to flow in a rigid bed. The magnitude of this bed load roughness is proportional to the thickness of the sediment layer moving along the bed, the particle size and the sediment concentration. In a supercritical flow, however, further resistance is expected due to the momentum absorption by the high flow velocity. In this study the effect of sediment movement on the flow resistance in supercritical flow was experimentally investigated. The experiments included flows over smooth and rough beds carrying sediment of mean diameters D 50 =2.80, 5.42 and 7.06 mm in a rigid rectangular channel. The results show that the sediment transport may increase the friction factor by up to 90% and 60% in smooth and rough beds, respectively. Bedload extracts its momentum from the flow, which causes a reduction of near bed flow velocity and steeper velocity gradient near the bed resulting in an increase in shear velocity as well as in roughness height. The increase in friction factor is directly related to bedload concentration and particle size.

关键词： Hydraulic resistance Friction factor Bedload transport Supercritical flow

Dynamics and bifurcations of a host-parasite model

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International Journal of Biomathematics 2017年第6期10卷 301-316页

作者： Ali Atabaigi mohammad hossein Akrami Department of Mathematics Razi University Kermanshah Iran Department of Mathematical Sciences Yazd University Yazd Iran

A two-parameter family of discrete models, consisting of two coupled nonlinear difference equations, describing a host-parasite interaction is considered. In particular, we prove that the model has at most one nontrivial interior fixed point which is stable for a certain range of parameter values and also undergoes a Neimark-Sacker bifurcation that produces an attracting invariant curve in some areas of the parameter.

关键词： Host-parasite Neimark-Sacker bifurcation local dynamics.

Selective monotetrahydropyranylation of symmetrical diols using P_20_5/Si0_2 under solvent-free conditions and their depyranylation

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Chinese Chemical Letters 2008年第9期19卷 1063-1067页

作者： hossein Eshghi mohammad Rahimizadeh Sattar Saberi Department of Chemistry Ferdowsi University of MashhadMashhad 91775-1436Iran

Selective protection of one of the hydroxyl group in 1, n-symmetrical diols is achieved by P2O5/SiO2-catalyzed reaction of the diol with dihydropyran under solvent-free conditions at room temperature. This selective protection is simple and it occurred under economically cheap conditions in high yield. The deprotected diol is simply obtained by refluxing of this compound in methanol using the same catalyst without any byproduct formation or additional purifications.

关键词： Heterogeneous catalyst P2O5/SiO2 Monotetrahydropyranylation Protecting group Symmetrical diols