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Comparing the Fatigue and Corrosion Behavior of Nanograin and Coarse-Grain IF Steels

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Acta Metallurgica Sinica(English Letters) 2015年第3期28卷 295-301页

作者： A.Chabok k.dehghani M.Ahmadi Jazani Mining and Metallurgical Engineering Department Amirkabir University of Technology

In the present work,a nanograin layer of about 150 μm thick was formed on the surface of an interstitial-free（IF） steel via friction stir ***,the fatigue and corrosion behaviors of IF steel with nanograin layer were compared with that of coarse-structure *** than threefold increase in the hardness was observed due to the formation of nanograin *** size of nanograms in the stir zone was within 30-150 *** resulted in 50%increase in the fatigue strength of nanostructured ***,the fracture surfaces were characterized using field emission scanning electron microscopy and scanning electron *** for the fatigue behavior of nanograin IF steel,the fracture surface was characterized by the formation of nanospacing striations and ***,the nanograin structure pronounced the passivity and exhibited higher corrosion resistance.

关键词： Nanograin Interstitial-free(IF) steel Fatigue Friction stir processing(FSP) Corrosion

Effect of Aging Time and Temperature on Mechanical Properties and Microstructural Evolution of 2205 Ferritic-Austenitic Stainless Steel

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Journal of Materials Science & Technology 2009年第5期25卷 597-602页

作者： H.keshmiri A.Momeni k.dehghani G.R.Ebrahimi G.Heidari Esfarayen Steel Complex Department of Mining and Metallurgy Amir Kabir University of Technology Tarbiat Moalem University of Sabzevar

Duplex stainless steels （DSS） with ferritic-austenitic microstructures offer good combination of resistance to pitting corrosion and high strength that are not concomitantly attainable using conventional single phase austenitic or ferritic stainless steels, The DSS used in this investigation was 2205 alloy having a stable microstructure consisting of about 45% ferrite and 55% austenite at ambient temperature. In order to investigate aging behavior of this steel and the influences on mechanical properties, different aging treatments were conducted at temperatures of 350-950℃ for various aging time of 15, 30, 60 and 180 min. The aged specimens were subjected to impact testing and hardness measurements. Finally, the changes in microstructure due to aging were studied by optical and scanning electron microscopy. The results showed that aging at temperatures lower than 550℃ for different time had negligible effects on mechanical properties. Besides, no considerable changes in term of precipitation of harmful intermetallic particles were observed in microstructure below this temperature. However, a critical temperature range, 550-650 ℃, was introduced here. Aging in this range led to a significant decrease in toughness and notable increase in hardness. The formation of intermetallic phases such as CT was recognized as the major reason for the observed changes.

关键词： Duplex stainless steel Aging Toughness Sigma phase

温度达到120℃时高岭石、石英及其混合物造成的碱耗

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国外油田工程 1999年第5期15卷 8-12页

作者： J.R.Johnson k.dehghani D.B.Hawkins 贾庆周斌大庆油田设计院

已经证实，通过几种不同的驱油机理热碱液能够提高原油的采收率、为了正确设计热碱驱，必须对高温条件下油藏矿物造成的碱耗加以考虑。本研究给出了在热碱液驱温度下，石英、高岭石和强碱进行一系列反应的实验结果。研究石英、高岭石及... 详细信息

已经证实，通过几种不同的驱油机理热碱液能够提高原油的采收率、为了正确设计热碱驱，必须对高温条件下油藏矿物造成的碱耗加以考虑。本研究给出了在热碱液驱温度下，石英、高岭石和强碱进行一系列反应的实验结果。研究石英、高岭石及其混合物在120℃条件下，与0.1N的NaOH溶液的反应情况，同时研究高岭石在70℃、100℃条件下的溶解性能。结果表明，在120℃条件下，80％石英和20％高岭石（按重量计）的混合物造成的碱耗，要等于或大于这些矿物单独存在时的碱耗。纯石英溶解与混合物溶解的主要区别是碱耗机理的不同，石英溶解时，氢氧根离子是与SiO2反应而被消耗。而纯高岭石或石英与高岭石的混合物与碱反应时，形成一种新的碱酸铝矿物。使大量的碱在不可逆的反应中被消耗掉；这种新的矿物被确认为合成沸石Na－Pc。当温层从100℃升至120℃时；高岭石碱耗的速率增加5倍。依照一级动力学可以得出高岭石溶解下采的Si和Al的初始速率，在阿仑尼乌斯数据曲线得出高岭石溶解下的Si和Al的假活化能分别为8.5和1.1kCal／mole。

关键词：提高的油采收率砂岩油藏驱油注碱水碱耗

温度达到120℃时高岭石、石英及其混合物造成的碱耗

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石油石化节能与计量 1999年第5期 8-12页

作者： J．R．Johnson,k.dehghani,D．B．Hawkins,贾庆,周斌大庆油田设计院大庆油田设计院

关键词：提高原油采收率砂岩油藏强碱驱油高岭石石英

Microstructural evolution and mechanical properties of nanostructured Cu-Al-Ni shape memory alloys

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 333-338页

作者： M. Izadinia k. dehghani Mining and Metallurgical Engineering Department Amirkabir University of Technology

The melt spinning technique, with an applied cooling rate of about 106 k/s, was used to produce a nanostructured Cu＋13.2Al＋ 5.1Ni （in wt%） shape memory alloy. The properties of nanostructured ribbons were then compared with those of conventional coarse struc- ture. The microstructural evolution was characterized using scanning electron microscopy （SEM）, atomic force microscopy （AFM） and X-ray diffraction （XRD） techniques. Microhardness measurements indicate a two-fold increase in hardness because of the produced nanos- lructure. Comparing to its coarse structure, the nanostructured Cu-A1-Ni shape memory alloy exhibited the enhanced mechanical properties including a ductility of 6.5% and a pronounced plateau in the stress-strain curve.

关键词： copper allosy shape memory effect melt spinning mechanical properties microstructural evolution

POLYROTAXANE WITH π-CONJUGATED PORPHYRIN AND POLYAZOMETHINE SYSTEMS PREPARED FROM A TYPE OF PORPHYRIN-DIALDEHYDE AND COMPLEX OF β-CYCLODEXTRIN WITH 1,4-PHENYLENEDIAMINE

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Chinese Journal of Polymer Science 2013年第1期31卷 139-147页

作者： Raziyeh Akbarzadeh Hossein dehghani Department of Inorganic Chemistry Faculty of ChemistryUniversity of Kashan

The synthesis of 5,15-bis[4-（methoxycarbonyl）phenyl]-10,20-diphenylporphyrin （2） and its reduction to 5,15- bis[4-（hydroxymethyl）phenyl]-10,20-diphenylporphyrin （3）, and so its oxidation to provide 5,15-bis（4-formylphenyl）-10,20- diphenylporphyrin （4） are reported. The copolymer possessing β-cyclodextrin （fl-CD）, n-conjugated porphyrin and polyazomethine systems was synthesized by the polycondensation of porphyrin-dialdehyde monomer （4） and ,β- cyclodextrin/1,4-phenylenediamine complex （5）. The monomers and the copolymer were characterized by UV-Vis, ^1H-NMR and IR spectra. Furthermore, ^1H-NMR and FT-IR spectra confirmed locating the aromatic ring of 1,4-phenylenediamine molecule in the center of β-cyclodextrin cavity.

关键词： Polymer Porphyrin 1,4-Phenylenediamine Imine Cyclodextrin.

Microstructural Evolution of NiTi47.7Cu6.3 Alloy during Hot Deformation

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Journal of Materials Science & Technology 2011年第10期27卷 951-960页

作者： Amir Etaati kamran dehghani Mining and Metallurgical Eng.Dept. Amirkabir Univ.Tech.

In the present work, the hot workability and microstructural evolution of ***6.3 （at.%） shape memory alloy were investigated by using wedge-rolling test. The wedge specimens were subjected to hot rolling at the temperatures of 700-1000℃. The microstructural evolutions at the strains of 0.05, 0.15, 0.2, 0.25 and 0.3 were then characterized by optical microscopy and scanning electron microscopy （SEM） as well as energy dispersive spectrometry （EDS） technique. Depending on the deformation temperature and strain, the dynamic recrystallization （DRX） could occur, leading to the refining of the microstructure. At low temperatures of 700 and 800℃ there was no sign of DRX at all studied strains. At these temperatures, the formed fine needle-like precipitates pinned the grain boundaries and prevented them from bulging/migration. By contrast, at higher temperatures of 900 and 1000℃, the DRX took place at the critical strains lower than 0.25 and 0.15, respectively. However, at higher temperatures, strain-induced-boundary-migration （SIBM） mechanism resulted in the formation of DRX grains.

关键词： Deformation Wedge rolling test Dynamic recrystallization Ni-rich Nitinol NiTiCu

Hot Ductility of Severe Plastic Deformed AA6061 Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第3期28卷 322-330页

作者： Ali Akbar khamei kamran dehghani Mining and Metallurgical Engineering Department Amirkabir University of Technology

The hot ductility of 6061 aluminum alloy,which was subjected to two different severe plastic deformations（SPD）,was studied at different temperatures and strain *** tensile tests were carried out at the temperature range of 300-500 ℃ and at the strain rates of 0.0005-0.01 s^（-1）.The microstructure evolution was characterized using optical microscopy,transmission electron microscopy and X-ray diffraction *** influences of the microstructure after SPD,thermomechanical parameters（temperature and strain rate） and specimen size on the hot formability of this alloy were then *** results show that a decrease in grains/subgrains exhibited significant effect on the hot ductility of SPDed *** constitutive equations were then developed to model the hot formability of the studied *** developed model can be represented by Zener-Hollomon parameter in a hyperbolic sinusoidal equation *** the changes of elongation to failure and Zener-Hollomon parameter indicate that the hot ductility of the alloy is more sensitive to the temperature rather than to the strain *** uniform elongation is independent of the specimen size,but the postnecking elongation increases dramatically as the ratio of l/A^（1/2） decreases.

关键词： Al-Mg-Si alloy Deformation behavior Equal channel angular pressing(ECAP) Rolling Hot tensile deformation

Investigating a potential reservoir landslide and suggesting its treatment using limit-equilibrium and numerical methods

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Journal of Mountain Science 2017年第3期14卷 432-441页

作者： Nima BABANOURI Hesam dehghani Department of Mining Engineering Hamedan University of Technology***HamedanIran

A reservoir landslide not only reduces the water storage capacity, but also causes extensive damages to the dam body, power/water transmission lines, roads, and other infrastructures. The Latian Dam, located 35 km north east of Tehran （Iran）, is one of the cases which has encountered serious problems with instability of its rock abutments. This paper addresses the stability analysis of the right abutment of the Latian Dam using limit equilibrium and numerical methods. Geomechanical characteristics of the rock abutment were first estimated based on engineering classification of the rock mass. Different search methods were examined for locating the critical circular/non-circular slip surface in conjunction with the general limit equilibrium method. The effect of variabi]ity of rock mass properties, water table, and earthquake load on the factor of safety （FS） and probability of failure （PF） was studied. In the event of rapid drawdown in the reservoir, the limit equilibrium analysis calculated FS=1.067 and PF=21.1%, and the numerical analysis returned FS=1.01. The results of the analyses suggest that the right abutment of the Latian Dam is prone to slide and needs treatment. Investigations demonstrated that a slope reduction by 15° at the upper part of the abutment would meet stability conditions even in the worst-case scenario （FS=1.297 and PF=2.07%）.

关键词： Reservoir landslide Limit equilibrium Numerical modeling Reliability Slope stabilization