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Journal of Materials Science & Technology 2010年第12期26卷 1078-1082页

作者： S.Ahmadi h.arabi A.Shokuhfar Department of Material Science Faculty of EngineeringTarbiat Modares UniversityTehranIran Center of Excellence of Advanced Materials and Processing(CEAMP) Department of Metallurgy and Materials Science and EngineeringIran University of Science & Technology(IUST)NarmakTehranIran Department of Material Science Faculty of Mechanical EngineeringK.N.Toosi University of TechnologyTehranIran

Effects of multiple strengthening treatments （i.e. ag mechanical properties and stability of nanoscale prec in this research. Various tests such as hardness, tensi ng either at three or four consecutive temperatures） on pitated phases in an AA2090 alloy have been evaluated e, electrical resistance, differential scanning calorimetric （DSC）, and transmission electron microscopy （TEM） have been performed. The results show that the ultimate tensile strength （UTS） and the yield strength of the samples aged at four consecutive temperatures （i.e. natural aging＋190℃＋150℃＋100℃） can be increased approximately to 660 and 610 MPa, respectively. It is also found that precipitation of T1 phase occurs during multiple aging process of the alloy and the higher amounts of enthalpies shown in DSC charts are linked to higher volume fraction of this precipitate. Furthermore, TEM observations reveal that T1 phase has plate shape morphology and its crystal structure is in the form of hcp with lattice parameters of a=0.467 nm and c=0.878 nm.

关键词： Multiple strengthening Thermo mechanical treatment (TMT) Selected area electron diffraction (SAED) pattern Inter planar spacing (d)

Evaluation of the Electroslag Remelting Process in Medical Grade of 316LC Stainless Steel

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Journal of Materials Science & Technology 2009年第5期25卷 592-596页

作者： S.Ahmadi h.arabi A.Shokuhfar A.Rezaei Institute of Advanced Technologies for Metallic Materials Tarbiat Modares University Center of Excellence of Advanced Materials and Processing(CEAMP) Department of Metallurgy and Materials Science and EngineeringIran University of Science&Technology(IUST) Department of Material Science Faculty of Mechanical EngineeringK.N.Toosi University of Technology

This study is focused on the effects of electroslag remelting by prefused slag （CaO, Al2O3, and CaF2） on macrostructure and reduction of inclusions in the medical grade of 316LC （316LVM） stainless steel. Analysis of the obtained results indicated that for production of a uniform ingot structure during electroslag remelting, shape and depth of the molten pool should be carefully controlled. high melting rates led to deeper pool depth and interior radial solidification characteristics, while decrease in the melting rates caused more reduction of nonmetallic inclusions. Large shrinkage cavities formed during the conventional casting process in the primary ingots were found to be the cause of the fluctuation in the melting rate, pool depth and extension of equiaxed crystals zone.

关键词： Ultra clean steel Electroslag Radial solidification remelting Prefused slag Vertical solidification

A Comparative Study of the Electronic and Magnetic Properties of Gd_5Ge_4 and Gd_5Si_4 Compounds

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Communications in Theoretical Physics 2014年第12期61卷 903-908页

作者： Z.Momeni Larimi A.Amirabadizadeh A.Yazdani h.arabi Department of Physics Faculty of Science University of Birjand P.O.Box 97175-615 Birjand Iran Tarbiat Modares University Tehran P.O.Box 14115-175 Iran Department of Physics Faculty of Basic Science Ferdowsi University Mashhad Iran

We present a comparative study of electronic structure and magnetic properties of Gd5Si4 and Gd5Ge4compounds using first principles full potential linearized augmented plane wave(FP-LAPW) method based on density functional theory(DFT) using the WIEN2 k code. The local-spin density approximation with correlation energy(LSDA+U) method has been used as the exchange-correlation potential. The optimized lattice constants are in good agreement with the experimental data. The total and partial density of states(DOS) of Gd5Si4 and Gd5Ge4show the difference in Si 3p-Gd 5d and Ge 4p-Gd 5d hybridization, which have an effective role in indirect exchange *** addition, the magnetic moments of Gd, Si, and Ge atoms and the compounds are calculated to clarify the differences in the magnetic properties of these compounds.

关键词： magnetocaloric compound density functional theory electronic and magnetic properties exchange interaction

Comparison of microstructural stability of IN939 superalloy with two different manufacturing routes during long-time aging

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Transactions of Nonferrous Metals Society of China 2014年第6期24卷 1717-1729页

作者： M.R.JAhANGIRI h.arabi S.M.A.BOUTORABI Metallurgy Department Niroo Research Institute School of Metallurgy and Materials Engineering Iran University of Science and Technology

Microstructural stability of IN939 superalloy with two different manufacturing routes was investigated during long-term aging at elevated temperatures by light optical microscope（OM） and scanning electron microscope（SEM） equipped with an EDS *** results show mat the coarsening behavior of γ＇ particles is primarily impacted by the initial heat treatment conditions,and the effect of the prior manufacturing route（casting or hot forming） is found to be insignificant,if any,on the γ＇ particles coarsening *** the temperature range of 790-827 ℃,IN939 cast/wrought-hT2 alloys have more microstructural stability,while in the temperature range of 827-910 ℃,the initial heat treatment marked as hT1 provides more stable microstructure for the cast or wrought IN939 superalloy.

关键词： nickel-based superalloy IN939 superalloy long-term coarsening manufacturing route heat treatment γ particles carbides

Microstructural evolution of copper-titanium alloy during in-situ formation of TiB_2 particles

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Transactions of Nonferrous Metals Society of China 2013年第10期23卷 2994-3001页

作者： M.SOBhANI h.arabi A.MIRhABIBI R.M.D.BRYDSON Center of Excellence for Advanced Materials and Processing School of Metallurgy and Materials Engineering Iran University of Science and Technology Center of Excellence for Ceramic Materials in Energy and Environmental Applications Iran University of Science and Technology Institute for Materials Research University of Leeds

Bulk Cu-Ti alloy reinforced by TiB2 nano particles was prepared using in-situ reaction between Cu 3.4%Ti and Cu-0.7%B master alloys along with rapid solidification and subsequent heat treatment for 1-10 h at 900 ℃. high-resolution transmission electron microscopy （hRTEM） characterization showed that primary TiB2 nano particles and TiB whiskers were formed by in-situ reaction between Ti and B in the liquid copper. The formation of TiB whiskers within the melt led to coarsening of TiB2 particles. Primary TiB2 particles were dispersed along the grain boundaries and hindered grain growth at high temperature, while the secondary TiB2 particles were formed during heat treatment of the alloy by diffusion reaction of solute titanium and boron inside the grains. Electrical conductivity and hardness of the composite were evaluated during heat treatment. The results indicated that the formation of secondary TiB2 particles in the matrix caused a delay in hardness reduction at high temperature. The electrical conductivity and hardness increased up to 8 h of heat treatment and reached 33.5% IACS and hV 158, respectively.

关键词： in-situ reaction TiB whiskers TiB2 particles Cu-Ti alloy composite

Mechanical and microstructural variations in ECAP of Ti-6Al-4V alloy with equiaxed microstructure

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Rare Metals 2022年第8期41卷 2732-2738页

作者： hamid arabi Mostafa Ketabchi S.h.N.Alhosseini Mining and Metallurgical Engineering Department Amirkabir University of TechnologyTehran***Iran University Complex of Material and Manufacturing Malek Ashtar University of TechnologyTehran***Iran

The aim of this study is to investigate mechanical and microstructural variations of Ti-6 Al-4 V acquired through various equal channel angular pressing(ECAP)*** ECAP of Ti-6 Al-4 V alloy with the first equiaxed micros tructure was carried out by an isothermal warm and isothermal die *** A pressing carried out on cylindrical samples at 650℃.Mechanical and microstructural investigations were performed concerning Ti-6 Al-4 V in the first state after 2,4,and 8 *** microscopy(OM)investigation shows that alpha grain size increases and beta grain size decreases with the pass numbers *** phase content initially decreases in the first two ECAP *** results show that more equiaxed alpha grains are achieved after four ECAP *** of X-ray diffraction(XRD)analysis show that crystallite size decreases with the number of passes *** two ECAP passes,a vivid increase in mechanical strength is observed;however,the increment dramatically slows down by the increasing number of passes.

关键词： Ti-6Al-4V alloy Equal channel angular pressing Equiaxed microstructure Mechanical properties

Investigation on the dissolution of η phase in a cast Ni-based superalloy

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International Journal of Minerals,Metallurgy and Materials 2013年第1期20卷 42-48页

作者： M.R. Jahangiri h. arabi S.M.A. Boutorabi School of Metallurgy and Materials Engineering Iran University of Science and Technology Metallurgy Department Niroo Research Institute Center of Excellence for Advanced Materials & Processing Iran University of Science and Technology

The dissolution behavior of rI phase has been investigated in a cast Ni-based superalloy. The results showed that the platelets and blocks of η phase were formed within the interdendritic regions of the microstructure. Applying standard solution annealing at 1150-1160℃ for a period of 4 h did not result in the complete dissolution of η phase. For the complete dissolution of η phase without residual incipient melting, a 2-step solution annealing has been recommended. After dissolution at high tem- peratures, the TI phase transforms to two MC-type carbides： one is enriched in Ti, Nb, and Ta, and the other is of （Zr,Ti）C type.

关键词： superalloys nickel alloys phase transitions dissolution heat treatment carbides

Mathematical modeling and simulation of the interface region of a tri-layer composite material,brass-steel-brass,produced by cold rolling

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International Journal of Minerals,Metallurgy and Materials 2009年第2期16卷 189-196页

作者： h. arabi S.h. Seyedein A. Mehryab B. Tolaminejad School of Metallurgy and Materials Engineering Iran University of Science and TechnologyIUSTNarmakTehranIran

The object of this study was to find the optimum conditions for the production of a sandwich composite from the sheets of brass-steel-brass. The experimental data obtained during the production process were used to validate the simulation program, which was written to establish the relation between the interface morphology and the thickness reduction amount of the composite. For this purpose, two surfaces of a steel sheet were first prepared by scratching brushing before inserting it between two brass sheets with smooth surfaces. Three sheets were then subjected to a cold rolling process for producing a tri-layer composite with various thick- nesses. The sheet interface after rolling was studied by different techniques, and the bonding strength for each rolling condition was determined by peeling test. Moreover, a relation between interfacial bonding strength and thickness reduction was found. The simulation results were compared with the experimental data and the available theoretical models to modify the original simulation program with high application efficiency used for predicting the behavior of the interface under different pressures.

关键词： sandwich composite cold rolling mathematical simulation metallic bonding interface

Neuroinflammation as a therapeutic target in huntington's disease

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Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine

Glial response in the midcingulate cortex in huntington’s disease

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Neural Regeneration Research 2025年第1期20卷 207-208页

作者： Thulani h.Palpagama Andrea Kwakowsky Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CenterUniversity of GalwayGalwayIreland

huntington’s disease(hD)is a genetic disease characterized by the progressive degeneration of the striatum and *** can present with a variety of symptoms that can broadly be classified into motor symptoms,inclusive of choreatic movements and rigidity,mood and psychiatric symptoms,such as depression and apathy,and cognitive symptoms,such as cognitive *** causal mutation underlying hD results from an expansion of a CAG repeat sequence on the IT15 gene,resulting in the formation and accumulation of a mutant huntingtin protein.

关键词： huntington degeneration cortex