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Journal of Magnesium and Alloys 2022年第9期10卷 2574-2587页

作者： Maryam Rahmati Keyvan Raeissi Mohammad Reza Toroghinejad amin hakimizad Monica Santamaria Department of Materials Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran Yekta Mobaddel Pars Co. Science and Technology CampusYazd UniversityYazd 89158-18411Iran Dipartimento di Ingegneria Università di PalermoViale Delle ScienzeEd.690128PalermoItaly

In this research,plasma electrolytic oxidation coatings were prepared on AZ31 Mg alloy in a silicate-based solution containing K_(2)TiF_(6) using bipolar and soft sparking waveforms with 10,20,and 30%cathodic duty *** coatings displayed a net-like surface morphology consisted of irregular micro-pores,micro-cracks,fused oxide particles,and a sintered *** to the incorporation of TiO_(2) colloidal particles and the cathodic pulse repair effect,most of the micro-pores were ***-term corrosion performance of the coatings was investigated using electrochemical impedance spectroscopy during immersion in 3.5 wt.%NaCl solution up to 14 *** coating grown by the soft sparking waveform with a 20%cathodic duty cycle having the lowest porosity(6.2%)and a sharp layer concentrated in F element at the substrate/coating interface shows the highest corrosion *** friction coefficient of this coating has remained stable during the sliding even under 5 N normal load,showing relatively higher wear resistance than other *** coating produced using the equivalent unipolar waveform,as the reference specimen,showed the highest friction coefficient and the lowest wear resistance despite its highest micro-hardness.

关键词： Plasma electrolytic oxidation Pulsed waveforms AZ31 Mg alloy Dipotassium titanium hexafluoride Corrosion resistance Wear resistance

Comparative analysis of unipolar and bipolar plasma electrolytic oxidation coatings on Al-Mg laminated macro composites

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Transactions of Nonferrous Metals Society of China 2024年

作者： Mohsen RASTEGARI Masoud ATAPOUR Aboozar TAHERIZADEH amin hakimizad Maryam RAHMATI Department of Materials Engineering， Isfahan University of Technology Yekta Mobaddel Pars Co.， Science and Technology Campus， Yazd University Dental Materials Research Center， Dental Research Institute， School of Dentistry， Isfahan University of Medical Sciences

Al-Mg laminated macro composites （LMC） have garnered attention due to their excellent mechanical properties and low density. However， their weak corrosion resistance has limited their industrial applications. Plasma electrolytic oxidation （PEO） has been explored as a potential solution to this issue by producing hard and thick oxide coatings on the surface of Al-Mg LMCs manufactured through hot extrusion bonding. In this study， PEO coatings were prepared on Al-Mg LMCs using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys. The techniques of FESEM/EDX， GIXRD， and electrochemical methods of Potentiodynamic polarization and EIS were carried out. The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one. The corrosion performance of the specimens' cut edge was investigated using electrochemical impedance spectroscopy （EIS） after 1， 8， and 12 hours of immersion in a 3.5%wt. NaCl solution. It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 hours of immersion， with an estimated corrosion resistance of 41.87 kΩ.cm2， which was approximately three times higher than that of the unipolar coating. Notably， no signs of galvanic corrosion were observed in the LMC， and only minor corrosion attacks were observed on the magnesium layer in some areas.

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Incorporation mechanism of colloidal TiO_(2) nanoparticles and their effect on properties of coatings grown on 7075 Al alloy from silicate-based solution using plasma electrolytic oxidation

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Transactions of Nonferrous Metals Society of China 2021年第12期31卷 3659-3676页

作者： Mehri HASHEMZADEH Keyvan RAEISSI Fakhreddin ASHRAFIZADEH amin hakimizad Monica SANTAMARIA Department of Materials Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran Yekta Mobaddel Pars Co. Science and Technology CampusYazd UniversityYazd 89158-18411Iran Dipartimento di Ingegneria Universitàdi PalermoViale Delle ScienzeEd.690128PalermoItaly

Plasma electrolytic oxidation(PEO)was applied using a pulsed unipolar waveform to produce Al_(2)O_(3)−TiO_(2) composite coatings from sol electrolytic solutions containing colloidal TiO_(2) *** sol solutions were produced by dissolving 1,3,and 5 g/L of potassium titanyl oxalate(PTO)in a silicate *** electron microscopy,energy dispersive spectrometry,X-ray diffraction,and Raman spectroscopy were applied to characterizing the *** behavior of the coatings was investigated using polarization and impedance *** results indicated that TiO_(2) enters the coating through all types of micro-discharging and is doped into the alumina *** higher level of TiO_(2) incorporation results in the decrease of surface micro-pores,while the lower incorporation shows a reverse *** was revealed that the higher TiO_(2) content makes a more compact outer layer and increases the inner layer thickness of the *** measurements revealed that the coating obtained from the solution containing 3 g/L PTO exhibits higher corrosion performance than that obtained in the absence of *** coating produced in the absence of PTO consists of γ-Al_(2)O_(3),δ-Al_(2)O_(3) and amorphous phases,while α-Al_(2)O_(3) is promoted by the presence of PTO.

关键词： Al alloy Al_(2)O_(3)−TiO_(2)coating plasma electrolytic oxidation potassium titanyl oxalate corrosion resistance

Self-repairing AlO-TiOcoatings fabricated through plasma electrolytic oxidation with various cathodic pulse parameters

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Transactions of Nonferrous Metals Society of China 2023年

作者： Mehri Hashemzadeh Keyvan Raeissi Fakhreddin Ashrafizadeh Frank Simchen amin hakimizad Monica Santamaria Thomas Lampke Department of Materials Engineering， Isfahan University of Technology Materials and Surface Engineering Group， Institute of Materials Science and Engineering， Chemnitz University of Technology Yekta Mobaddel Pars Co.， Science and Technology Campus， Yazd University Dipartimento di Ingegneria， Università di Palermo， Viale Delle Scienze

The influence of cathodic pulse parameters was evaluated on PEO coatings grown on 7075 aluminum alloy in a silicate-based electrolyte containing potassium titanyl oxalate (PTO) using pulsed bipolar waveforms with various cathodic duty cycles and cathodic current densities. The coatings were characterized by SEM， EDS， and XRD. EIS was applied for investigating the electrochemical properties. It was observed that the increase of cathodic duty cycle and cathodic current density from 20% and 6 A dm-2to 40% and 12 A dm-2enhances the growth rate of the inner layer from 0.22 μm min-1to 0.75 μm min-1. Adding PTO into the bath showed a fortifying effect on influence of the cathodic pulse and the mentioned change of cathodic pulse parameters resulted in an increase of the inner layer growth rate from 0.25 to 1.10 μm min-1. Based on EDS analysis， Si and Ti were incorporated dominantly in the upper parts of the coatings. XRD technique merely detected γ-Al2O3， and there were no detectable peaks related to Ti and Si compounds. However， the EIS results confirmed that the incorporation of Ti4+into alumina changed the electronic properties of the coating. The coatings obtained from the bath containing PTO using the bipolar waveforms with a cathodic duty cycle of 40% and current density values higher than 6 A dm-2showed highly appropriate electrochemical behavior during 8 months of immersion due to an efficient repairing mechanism. Regarding the effects of studied parameters on the coating properties， the roles of cathodic pulse parameters and PTO in the PEO process were highlighted.

关键词：

Self-repairing Al_(2)O_(3)-TiO_(2)coatings fabricated through plasma electrolytic oxidation with various cathodic pulse parameters

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Transactions of Nonferrous Metals Society of China 2024年第10期34卷 3326-3343页

作者： Mehri HASHEMZADEH Keyvan RAEISSI Fakhreddin ASHRAFIZADEH Frank SIMCHEN amin hakimizad Monica SANTAMARIA Thomas LAMPKE Department of Materials Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran Materials and Surface Engineering Group Institute of Materials Science and EngineeringChemnitz University of TechnologyChemnitz 09107Germany Yekta Mobaddel Pars Co. Science and Technology CampusYazd UniversityYazd 89158-18411Iran Dipartimento di Ingegneria Universitàdi PalermoViale Delle ScienzeEd.690128PalermoItaly

The influence of cathodic pulse parameters was evaluated on plasma electrolytic oxidation(PEO)coatings grown on 7075 aluminum alloy in a silicate-based electrolyte containing potassium titanyl oxalate(PTO)using pulsed bipolar waveforms with various cathodic duty cycles and cathodic current *** coatings were characterized by SEM,EDS,and *** was applied to investigate the electrochemical *** was observed that the increase of cathodic duty cycle and cathodic current density from 20%and 6 A/dm^(2) to 40%and 12 A/dm^(2) enhances the growth rate of the inner layer from 0.22 to 0.75μm/*** PTO into the bath showed a fortifying effect on influence of the cathodic pulse and the mentioned change of cathodic pulse parameters,resulting in an increase of the inner layer growth rate from 0.25 to 1.10μm/*** on EDS analysis,Si and Ti were incorporated dominantly in the upper parts of the *** technique merely detectedγ-Al_(2)O_(3),and there were no detectable peaks related to Ti and Si ***,the EIS results confirmed that the incorporation of Ti^(4+)into alumina changed the electronic properties of the *** coatings obtained from the bath containing PTO using the bipolar waveforms with a cathodic duty cycle of 40%and current density values higher than 6 A/dm^(2) showed highly appropriate electrochemical behavior during 240 d of immersion due to an efficient repairing *** the effects of studied parameters on the coating properties,the roles of cathodic pulse parameters and PTO in the PEO process were highlighted.

关键词： Al_(2)O_(3)-TiO_(2)coating plasma electrolytic oxidation potassium titanyl oxalate electrochemical impedance spectroscopy

阴极脉冲参数对等离子体电解氧化制备自修复Al2O3-TiO2涂层的影响（英文）

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Transactions of Nonferrous Metals Society of China 2024年第10期 3326-3343页

作者： Mehri HASHEMZADEH Keyvan RAEISSI Fakhreddin ASHRAFIZADEH Frank SIMCHEN amin hakimizad Monica SANTAMARIA Thomas LAMPKE Department of Materials Engineering Isfahan University of Technology Materials and Surface Engineering Group Institute of Materials Science and EngineeringChemnitz University of Technology Yekta Mobaddel Pars Co. Science and Technology Campus Yazd University Dipartimento di Ingegneria Università di Palermo

在含草酸钛钾（Potassium titanyl oxalate, PTO）的硅酸盐电解液中采用不同阴极占空比和阴极电流密度的脉冲双极波形，在7075铝合金上生长等离子电解氧化（Plasma electrolytic oxidation, PEO）涂层，研究阴极脉冲参数对PEO涂层的影... 详细信息

在含草酸钛钾（Potassium titanyl oxalate, PTO）的硅酸盐电解液中采用不同阴极占空比和阴极电流密度的脉冲双极波形，在7075铝合金上生长等离子电解氧化（Plasma electrolytic oxidation, PEO）涂层，研究阴极脉冲参数对PEO涂层的影响。通过扫描电子显微镜、能量色散X射线光谱（EDS）和X射线衍射（XRD）对涂层进行了表征。使用电化学阻抗谱（Electrochemical impedance spectroscopy, EIS）研究其电化学性能。结果表明，当阴极占空比和阴极电流密度分别从20%和6 A/dm2增加到40%和12 A/dm2时，内层的生长速率从0.22μm/min提高到0.75μm/min。向电解液中加入PTO增强了阴极脉冲的影响，由此产生的阴极脉冲参数的变化使得内层生长速率从0.25μm/min增加到1.10μm/min。EDS分析结果表明，Si和Ti主要分布在涂层的上部。XRD仅检测到γ-Al2O3，未检测到与Ti和Si化合物相关的峰。然而，EIS结果证实，Ti4+掺入氧化铝改变了涂层的电性能。在含有PTO的电解液中使用40%阴极占空比和大于6 A/dm2电流密度的双极波形获得的涂层，在240 d的浸泡期间表现出优异的电化学行为，这归因于有效的修复机制。关于研究参数对涂层性能的影响，强调了阴极脉冲参数和PTO在PEO过程中的作用。

关键词： Al2O3-TiO2涂层等离子电解氧化草酸钛钾电化学阻抗谱

Geometrically Nonlinear Bending Analysis of Metal-Ceramic Composite Beams under Thermomechanical Loading

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Chinese Journal of Mechanical Engineering 2013年第4期26卷 701-713页

作者： TORABIZADEH Mohammad amin Department of Industrial Design Engineering University of Applied Science and Technology

A new method is developed to derive equilibrium equations of Metal-Ceramic beams based on first order shear deformation plate theory which is named first order shear deformation beam theory2(FSDBT2). Equilibrium equations obtained from conventional method (FSDBT1) is compared with FSDBT2 and the case of cylindrical bending of Metal-Ceramic composite plates for non-linear thermomechanical deformations and various loadings and boundary conditions. These equations are solved by using three different methods (analytical, perturbation technique and finite element solution). The through-thickness variation of the volume fraction of the ceramic phase in a Metal-Ceramic beam is assumed to be given by a power-law type function. The non-linear strain-displacement relations in the von-Kármán sense are used to study the effect of geometric non-linearity. Also, four other representative averaging estimation methods, the linear rule, Mori-Tanaka, Self-Consistent and Wakashima-Tsukamoto schemes, by comparing with the power-law type function are also investigated. Temperature distribution through the thickness of the beams in thermal loadings is obtained by solving the one-dimensional heat transfer equation. Finally it is concluded that for Metal-Ceramic composites, these two theories result in identical static responses. Also the displacement field and equilibrium equations in the case of cylindrical bending of Metal-Ceramic plates are the same as those supposed in FSDBT2.

关键词： thermomechanical loading functionally graded beams monlinear analysis analytical solution

Crack detection of the cantilever beam using new triple hybrid algorithms based on Particle Swarm Optimization

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Frontiers of Structural and Civil Engineering 2022年第9期16卷 1127-1140页

作者： amin GHANNADIASL Saeedeh GHAEMIFARD Department of Civil Engineering University of Mohaghegh ArdabiliArdabil 56199-11367Iran

The presence of cracks in a concrete structure reduces its performance and increases in the size of cracks result in the failure of the ***,the accurate determination of crack characteristics,such as location and depth,is one of the key engineering issues for assessment of the reliability of *** paper deals with the inverse analysis of the crack detection problems using triple hybrid algorithms based on Particle Swarm Optimization(PSO);these hybrids are Particle Swarm Optimization-Genetic Algorithm-Firefly Algorithm(PSO-GA-FA),Particle Swarm Optimization-Grey Wolf Optimization-Firefly Algorithm(PSO-GWO-FA),and Particle Swarm Optimization-Genetic Algorithm-Grey Wolf Optimization(PSO-GA-GWO).A strong correlation exists between the changes in the natural frequency of a concrete beam and the crack ***,the location and depth of a crack in a beam can be predicted by measuring its natural ***,the measured natural frequency can be used as the input parameter of the *** this paper,this is applied to identify crack location and depth in a cantilever beam using the new hybrid *** results show that among the proposed triple hybrid algorithms,the PSO-GA-FA and PSO-GWO-FA algorithms are much more effective than PSO-GA-GWO algorithm for the crack detection.

关键词： crack cantilever beam triple hybrid algorithms Particle Swarm Optimization

Effect of the spectral shape of ground motion records on the collapse fragility assessment of degrading SDOF systems

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Earthquake Engineering and Engineering Vibration 2021年第4期20卷 925-941页

作者： amin Norouzi Mehdi Poursha Department of Civil Engineering Sahand University of TechnologyTabriz 51335-1996Iran Earthquake Engineering Research Center Sahand University of TechnologyTabriz 51335-1996Iran

The main purpose of this paper is to study the collapse capacity of single degree of freedom(SDOF)systems and to produce fragility curves as well as collapse capacity spectra while considering a broad range of structural parameters,including system degradation,the P-Δeffect,ductility capacity and the post-capping stiffness *** modified Ibarra-Krawinkler deterioration model was used to consider hysteretic behavior.A comprehensive study was conducted to extract the collapse capacity spectrum of SDOF systems with a wide range of periods,varying from 0.05 to 4 s,to cover short,intermediate and long *** dynamic analysis(IDA)was performed for SDOF systems to identify the condition in which the collapse capacity of the system is *** IDAs were performed using different sets of seismic ground *** ground motion records were categorized into different sets based on three spectral shape parameters,including the epsilon,SaRatio and N_(p).The collapse fragility curves of SDOF systems with different periods were extracted to illustrate the collapse capacity at different probability *** results show that structural degradation and ductility as well as the spectral shape parameters significantly affect the collapse capacity of SDOF *** the other hand,the post-capping stiffness ratio and small levels of the P-Δeffect do not remarkably change collapse ***,the collapse capacity of SDOF systems is more sensitive to the records categorized based on SaRatio and N_(p)than those classified based on epsilon.

关键词： collapse capacity fragility analysis degrading SDOF system IDA curve Epsilon,N_(p) SaRatio P-Δeffect

THREE NONTRIVIAL SOLUTIONS FOR A NONLINEAR ANISOTROPIC NONLOCAL EQUATION

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Acta Mathematica Scientia 2018年第4期38卷 1296-1310页

作者： amin ESFAHANI School of Mathematics and Computer Science Damghan University

In this article, we establish the existence of a sign-changing solution and two sign- constant solutions for nonlinear nonlocal problem involving the BO-ZK operator on bounded domain. Our main tool is constrained mini... 详细信息

关键词： sign-constant and nodal solutions BO-ZK operator variational method