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Highly sensitive determination of promazine in pharmaceutical and biological samples using a ZnO nanoparticle-modified ionic liquid carbon paste electrode

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Chinese Chemical Letters 2016年第5期27卷 779-782页

作者： Vahid Arabali mahmoud ebrahimi Hassan Karimi-Maleh Department of Chemistry Mashhad Branch Islamic Azad University Mashhad Iran Department of Chemistry Graduate University of Advanced Technology Kerman Iran

In this work we describe the first report for the determination of promazine using a nanostructure- modified ionic liquid carbon paste electrode in aqueous solutions. To achieve this goal, a novel modified carbon paste electrode using ZnO nanoparticles and l-methyl-3-butylimidazolium bromide as a binder （ZnO/NPs/ILs/CPE） was fabricated. The oxidation peak potential of promazine at the surface of the ZnO/ NPs/ILs/CPE appeared at 685 mV, which was about 65 mV lower than the oxidation potential at the surface of CPE under similar conditions. Also, the peak current was increased to about 4.0 times higher at the surface of ZnO/NPs/ILs/CPE compared to that of CPE. The linear response range and detection limit were found to be 0.08-450 and 0.04 μmol/L, respectively. The modified electrode was successfully used for the determination of promazine in real samples with satisfactory results.

关键词： Promazine ZnO nanoparticle Ionic liquid Modified electrode

Microstructure and impact behavior of Mg-4Al-5RE-xGd cast magnesium alloys

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Journal of Magnesium and Alloys 2024年第5期12卷 1799-1814页

作者： Jie Wei Qudong Wang Huisheng Cai mahmoud ebrahimi Chuan Lei National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This work investigated the microstructure and impact behavior of Mg-4Al-5RE-xGd(RE represents La-Ce mischmetal;x=0,0.2,0.7 wt.%)alloys cast by high-pressure die casting(HPDC),permanent mold casting(PMC),and sand casting(SC)*** results indicated that with increasing Gd content,the grain sizes of the HPDC alloy had a slight change,but the grains of the PMC and SC alloys were significantly ***,the acicular Al_(11)RE_(3)phase was modified into the short-rod shape under the three casting *** impact toughness of the studied alloy was mainly dominated by the absorbed energy during the crack *** increasing Gd content,the impact toughness of the studied alloy monotonically increased due to the lower tendency of the modified second phase toward crack *** impact stress was higher than the tensile stress,exhibiting a strain rate sensitivity for the mechanical response;however,the HPDC alloy had an inconsistent strain rate sensitivity during the impact event due to the transformation of the deformation mechanism from twinning to slip with increasing *** dimples covered the fracture surface of the fine-grained HPDC alloys,indicating a typical ductile ***,due to the deficient{1012}twinning activity and the suppressed grain boundary sliding during the impact event,the HPDC alloys showed insufficient plastic deformation capacity.

关键词： Mg-Al-RE alloy Gadolinium Microstructure Impact behavior

Damping performance of SiC nanoparticles reinforced magnesium matrix composites processed by cyclic extrusion and compression

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Journal of Magnesium and Alloys 2023年第5期11卷 1608-1617页

作者： mahmoud ebrahimi Li Zhang Qudong Wang Hao Zhou Wenzhen Li National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites School of Material Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240PR China School of Mechanical Engineering North University of ChinaTaiyuan 030051PR China Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094PR China School of Materials Science and Engineering Tsinghua UniversityBeijing 10084PR China

This work dealt with the damping performance and its underlying mechanism in SiC nanoparticles reinforced AZ91D composite(SiC_(np)/AZ91D)processed by cyclic extrusion and compression(CEC).It was found that the CEC process significantly affects the damping performance of the composite due to alterations in the density of dislocations and grain boundaries in the matrix *** there would be dynamic precipitation of the Mg17Al12 phase during processing which increases the phase interface and limits the mobility of dislocations and grain *** results also showed that the damping capacity of 1%SiC_(np)/AZ91D composite continuously decreases with adding CEC pass number and it consistently increases with rising the applied *** the first derivative of the tanδ-T curve,the dominant damping mechanism based on test temperature can be divided into three *** three regions are as follows(i)dislocation vibration of the weak pinning points(≤T_(cr)),(ii)dislocation vibration of the strong pinning points(T_(cr)∼T_(V)),and(iii)grain boundary/interface sliding(≥T_(V))

关键词： Metal matrix composite SiC nanoparticles Severe plastic deformation Temperature-dependent damping curves Damping mechanism

Rapid cooling effect during solidification on macro-and micro-segregation of as-cast Mg–Gd alloy

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Progress in Natural Science:Materials International 2021年第1期31卷 68-76页

作者： Xin Tong Guoqiang You Jingchuan Luo mahmoud ebrahimi Guohua Wu National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong University College of Materials Science and Engineering Chongqing University National Engineering Research Center for Magnesium Alloys Chongqing University Department of Mechanical Engineering Faculty of Engineering University of Maragheh

The high performance of as-cast Mg-RE alloys is always related to their high RE ***,RE elements can be readily segregated in Mg alloys and the segregation becomes more significant with the increasing RE *** this research,the effect of cooling rate on the macro-and micro-segregation in the as-cast Mg-8 Gd alloy was *** Gd content at the bottom of the fabricated ingot with the cooling rate of 4.6-6.9℃/s was～1.7 times of that at the top and coarse eutectics as well as some non-equilibrium phases of α-Gd,MgGd,Mg;Gd were distributed along the grain *** formation mechanisms of the specific gravity segregation and grain boundary segregation were also *** the application of the water-cooled copper mold with the cooling rate of 27-200℃/s,only fine Mg5 Gd and some nanoscale metastable β;and β’ phases were found to disperse uniformly in the grain interior,thus the homogeneity of the composition,microstructure,and performance within the whole ingot was considerably *** is expected that these results will facilitate the processing design for the fabrication of the highly-homogenized Mg-RE alloy castings.

关键词： As-cast Mg–Gd alloy Segregation Rapid cooling Solidification Sedimentation

Segregation behavior and its regulating process in as-cast magnesium alloy containing heavy rare earth

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Journal of Rare Earths 2022年第8期40卷 1291-1304页

作者： Xin Tong Guoqiang You Fanjin Yao mahmoud ebrahimi Xinyue Deng Shokouh Attarilar College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Department of Mechanical Engineering Faculty of EngineeringUniversity of MaraghehP.O.Box 55136-533MaraghehIran School of Materials Science and Engineering Iran University of Science and TechnologyTehranIran

Specific gravity segregation that occurs during the smelting process always leads to the low composition homogeneity and poor performance stability of the magnesium-rare earth(Mg-RE)*** this study,the segregation behavior of Mg-Gd alloy was investigated by sampling from different locations in the ingot fabricated in a resistance furnace without a pouring *** combined application of induction-heating and mechanical stirring with various speeds(0-130 r/min)was applied to promote the distribution homogeneity of Gd *** the resistance-heating fabricated ingot,Gd content at the bottom section reaches 407%of that at the *** coarse dendrites surrounded by the network-like eutectic structures are responsible for the brittle fracture with a poor elongation of 3.7%.By the combined employment of the induction heating and mechanical stirring with the speed of 87 r/min at 740℃for 40 s,the variation of the Gd content within the whole ingot can be reduced to be the minimum of 0.23 wt%.Corresponding formation and regulating models of segregation were also ***,the cooling rate of the melt is reduced by the continuous increase of the stirring speed to 130 r/min,which results in the grain coarsening and lower homogeneity of the ingot.

关键词： Mg-RE alloy Segregation Composition homogeneity Melting process Mechanical stirring Rare earths

Effects of Gd Addition on the Microstructure and Tensile Properties of Mg–4Al–5RE Alloy Produced by Three Different Casting Methods

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Acta Metallurgica Sinica(English Letters) 2021年第10期34卷 1361-1374页

作者： Jie Wei Qudong Wang Li Zhang mahmoud ebrahimi Haiyan Jiang Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This work deals with the effect of 0.67 wt%Gd addition on the microstructure and tensile properties of Mg–4 Al–5 RE(where RE represents La–Ce mischmetal)alloy produced by sand casting(SC),permanent mold casting(PMC),and high-pressure die casting(HPDC).The results show that Gd addition could refine the grains,but its efficiency decreases by increasing the cooling rate due to the shifting from SC to PMC and finally to the HPDC ***,the acicular Al11 RE3 phase is modified into the short-rod or granular-like shape under the three casting *** refined and modified microstructures are due to the Al2(Gd,RE)phases,which act as the nucleation sites in both theα-Mg matrix and Al11 RE3 ***,the weakening grain refinement effect in the increased cooling rates can be attributed to the narrow constitutional undercooling *** Gd addition,the 0.2%proof strength of the SC and PMC alloys increases by about 16.9%and 12.7%,respectively,while in the HPDC alloy,it decreases by about 5.9%.The main factor in the strength increment of the SC and PMC alloys is the grain boundary strengthening due to grain refinement which is proved by modeling the related mechanisms,whereas weak secondary phases and grain boundary strengthening mechanisms in the HPDC alloy lead to strength *** Gd addition,the elongation to failure of the SC,PMC,and HPDC alloys is significantly enhanced by about 34.8%,20.2%,and 12.3%,respectively,due to the crack resistance nature of the modified short-rod/granular Al11(RE,Gd)3 phase compared to the acicular one.

关键词： Magnesium alloy Gadolinium Grain refinement Strengthening mechanism

Review on corrosion resistance of mild steels in liquid aluminum

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Journal of Materials Science & Technology 2021年第12期71卷 12-22页

作者： Gaopeng Xu Kui Wang Xianping Dong Lei Yang mahmoud ebrahimi Haiyan Jiang Qudong Wang Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of High Temperature Materials and Precision Forming Shanghai Jiao Tong UniversityShanghai 200240China Nano Life Science Institute(WPI-NanoLSI) Kanazawa UniversityKakuma-machiKanazawa 920-1192Japan COMP Centre of Excellence Department of Applied PhysicsAalto UniversityHelsinki FI-00076Finland

The corrosion of mild steels by liquid aluminum is an intractable issue in aluminum *** review aims to provide an overview of the corrosion behavior of mild steels in the static liquid aluminum with an emphasis on the thermodynamic and kinetic *** corrosion mechanisms of mild steels in liquid aluminum are discussed systematically,based on which four corrosion control approaches including alloying,introducing secondary phase,matrix microstructure control and surface treatment are ***,a combination of improvement approaches may have a great potential for further enhancement in corrosion resistance.

关键词： Corrosion resistance Liquid aluminum Mild steel Microstructure Control Surface treatment

Characteristic investigation of trilayered Cu/Al8011/Al1060 composite:Interface morphology, microstructure, and in-situ tensile deformation

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Progress in Natural Science:Materials International 2021年第5期31卷 679-687页

作者： mahmoud ebrahimi Guoping Liu Chuanwei Li Qudong Wang Haiyan Jiang Wenjiang Ding Fengling Su Zhengping Shang National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong University Institute of Materials Modification and Modeling School of Materials Science and Engineering Shanghai Jiao Tong University Sichuan Winner Special Electronic Materials Co. Ltd. Jiangsu Zhongse Composite Materials Co. Ltd.

In this work, Cu/Al8011/Al1060 trilayered composite with an ultrathin copper layer was fabricated successfully by the hybrid process of cast-rolling and hot-roll-bonding. The effects of heat treatment were investigated on the microstructure and mechanical behavior of the composite. The results showed that annealing temperatures above 300°C led to the formation of new intermetallic compounds that joined their initial counterparts. Also, the interface growth was fast above 340°C. It was found that the annealing temperature of 320°C led to the optimal tensile properties of the composite. Through rolling, hard-brittle IMCs imposed intense plastic strains on the surrounding regions, resulting in further grain refinement of both metals in the vicinity of the interface. Although the kernel average misorientation of the trilayered composite was almost identical with the Cu/Al8011 bimetal,its amount was considerably decreased after heat treatment, as the distorted structure changed into a nearly strain-free one using the restoration phenomenon. The SEM-based in-situ tensile test showed that crack initiation occurred within the IMCs and propagated into the Cu strip, leading to its early fracture. However, the strengthdisplacement curve during in-situ tensile deformation did not decrease significantly due to the ultrathin copper layer.

关键词： Heat-treatment Intermetallic compounds Mechanical properties Kernel average misorientation Microstructure analysis Crack initiation

Enhancing mechanical properties and corrosion performance of AA6063 aluminum alloys through constrained groove pressing technique

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Transactions of Nonferrous Metals Society of China 2020年第7期30卷 1790-1802页

作者： Ren-jie FAN Shokouh ATTARILAR mahmoud SHAMSBORHAN mahmoud ebrahimi Ceren GODE Hatice VarolOZKAVAK Department of Mechanical Engineering Tongling Vocational and Technical CollegeTongling 244061China School of Metallurgy and Materials Engineering Iran University of Science and TechnologyTehranIran Department of Engineering Mahabad BranchIslamic Azad UniversityMahabadIran Department of Mechanical Engineering University of ZakhoZakhoKurdistan RegionIraq Department of Mechanical Engineering Faculty of EngineeringUniversity of MaraghehMaraghehIran School of Denizli Vocational Technology Program of MachinePamukkale UniversityDenizliTurkey Department of Mechanical and Metal Technology Technical Sciences Vocational SchoolIsparta University of Applied SciencesIspartaTurkey

The use of a constrained groove pressing(CGP) method to plastically deform AA6063 aluminum alloy led to the improved surface properties. It was found that hardness magnitude is dramatically improved and its uniformity is considerably decreased after the first pass, while subsequent passes result in better hardness behavior for the processed material. Also, the elongated grains formed in the first pass of the CGP are gradually converted to the equiaxed counterparts by adding pass numbers. Eventually, higher corrosion resistance of the sample by imposing the CGP process is related to the quick formation of passivation film and the change in the morphology of the second phase and precipitates which hinder their electrochemical reactions and decrease the potential localized attack sites.

关键词： mechanical properties corrosion resistance aluminum alloy constrained groove pressing technique grain refinement hardness distribution homogeneity