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Rare Metals 2014年第1期33卷 16-20页

作者： Yang-Yang liu fu-shun liu School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics

The effects of heat treatments on the phase transformation behavior of Ti49Ni49.5Fe1V0.5and Ti48Ni48.5Fe1V2.5 alloys were investigated. The results indicate that the alloys subjected to different heat treatments have B2 structure at room temperature. All the specimens exhibit a twostage B2 → R → B19r martensitic transformation on cooling, but a B19’ → B2 one-stage reverse martensitic transformation on heating except aged A1 alloy, which undergoes an abnormal two-stage transformation upon heating. The phase transformation temperatures are affected by heat treatments and V content, which can be attributed to the variation of the second-phase particles content in the matrix.

关键词： Keywords Heat treatments Phase transformationbehavior Ti-Ni-Fe-V alloy Second-phase particles

Phase transformation behavior and mechanical properties of Ti_(50)Ni_(49-x) Fe_1Co_x shape memory alloys

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Rare Metals 2013年第3期32卷 225-227页

作者： Bin Chen fu-shun liu School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics

In this article, the influence of Co addition on phase transformation behavior and mechanical properties of TiNiFe shape memory alloy was investigated extensively. Differential scanning calorimetry （DSC） measurements shows that martensitic start transformation temperatures （Ms） decrease drastically with increasing Co content, while the R phase transformation start temperatures （Rs） vary slightly. Nevertheless, the substitution of Ni with Co does not exert substantial influence on the two-stage transformation behavior of the TiNiFe alloy. The results from stress-strain curves indicate that higher critical stress for stress-induced martensitic transformation （σSIM） has been obtained because of Co addition. In such cases, the Ti50Ni48sFelCO1.0 alloy maintains a good shape memory effect, and a maximum recoverable strain of 7.5 % can be obtained.

关键词： Ms σSIM Shape memory effect

Microstructures of Ti–Ni–Fe wire after severe cold-drawing and annealing

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Rare Metals 2013年第6期32卷 550-554页

作者： Hui-Fang Geng fu-shun liu School of Material Science and Engineering Beijing University of Aeronautics and Astronatics

The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were intensively investigated using transmission electron microscope(TEM),X-ray diffraction(XRD),Vickers microhardness tester and electron tensile *** is indicated that the structure of the alloy evolves into a predominant amorphous structure with a trace of nanocrystalline B2 phase after the cold-drawing of 76%areal *** annealing process exerted significant influence on the microstructure and mechanical *** occurs when the cold-drawn wire was annealed at 300℃ for 30 *** ultimate tensile strength and ductility as well as the superelasticity of the wire are improved significantly by cold-drawing plus postdeformation annealing.

关键词： Ti–Ni–Fe wire Severe plastic deformation Cold-drawing Annealing Amorphous structure

Phase transformation behaviors and mechanical properties of Ti_(50)Ni_(49)Fe_1 alloy with severe plastic deformation

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Rare Metals 2013年第5期32卷 448-452页

作者： Wen Ma Bin Chen fu-shun liu Qing Xu Division of Science and Technology Information General Research Institute for Nonferrous Metals School of Material Science and Engineering Beijing University of Aeronautics and Astronautics Metrology and Phsico-Chemical Institute Capital Aerospace Machinery Company

In this work, transformation behaviors and mechanical properties of cold-rolled shape memory alloy TisoNia9Fel by severe plastic deformation （SPD） were intensively investigated. The phase transformation behaviors, phase analysis, and microstructures were characterized by differential scanning calorimetry （DSC）, X-ray diffraction （XRD）, and transmission electron microscopy （TEM）, respectively. Tensile testing was performed to analyze the effect of SPD on the mechanical properties and shape memory of TisoNi49Fel alloy. When the thickness reduction is beyond 30 %, the martensitic transformation is suppressed. After cold-rolling, the alloy is mainly com- posed of B2 parent phases with some stress-induced martensitic B 19t phases, and high density of dislocations are generated and the grains are obviously refined. The yield stress ab significantly raises from 618 MPa of 0 % cold rolling to 1,338 MPa of 50 % SPD. Shape-memory effect increases from 6.5 % without cold rolling to 8.5 % after 30 % SPD, ascribed to the induced defects in cold rolling. Those results indicate that TisoNi49Fel alloy has improved mechanical properties and potential commercial applications after SPD.

关键词： TiNiFe alloy Cold-rolling Severe plasticdeformation (SPD) Shape memory effect

Crystallization behavior in severely cold-drawn Ti_(50) Ni_(47) Fe_3 wire

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Rare Metals 2014年第3期33卷 258-262页

作者： Xin-Quan Zhang Hui-Fang Geng fu-shun liu Wen Ma The Integrated Standard and Material Application Research Department AVIC The First Aircraft Institute School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Division of Science and Technology Information General Research Institute for Nonferrous Metals

The microstructures and crystallization behavior of Ti-47 at% Ni-3 at% Fe shape memory alloy wire under the condition of severe cold drawing at room temperature and different post-deformation annealing processes were intensively investigated using transmission electron microscope（TEM） and differential scanning calorimetry（DSC）. It is indicated that the amorphous phase is dominant in the Ti50Ni47Fe3 wire after the cold drawing of 78 % areal reduction. The critical temperature for recrystalization is determined at about 300 °C. The average grain size grows from 7 up to 125 nm when annealing temperature rises from300 to 500 °C. Post-deformation annealing process exerts significant influence on the crystallization temperature which climbs up with the increase of annealing temperature.

关键词： TisoNi47Fe3 wire Cold drawing Annealing Amorphous Crystallization

Transformation behaviors and superelasticity of Ti_(50)Ni_(48)Fe_2 shape memory alloy subjected to cold-rolling and subsequent annealing

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Rare Metals 2014年第6期33卷 652-656页

作者： Xiao-Bo Yuan Bin Chen fu-shun liu Qing Xu Wen Ma School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Capital Aerospace Machinery Company Division of Science & Technology Information General Research Institute for Nonferrous Metals

The effects of annealing on the phase transformation behavior and superelasticity of cold-rolled Ti50Ni48Fe2 shape memory alloy were extensively investigated. Curves of temperature dependence of electrical resistivity reveal that both the cold-rolled and annealed specimens exhibit a B2→R→B19’two-stage martensitic transformation upon cooling and a B19’→B2 one-stage transformation upon heating, although the austenitic transformation temperature decreases with the increase of the annealing temperature. Tensile stress–strain curves show the critical stress for stress-induced martensite（rSIM）of Ti50Ni48Fe2 alloys decreases with the increase of annealing temperature due to the decrement of dislocation density caused by the recrystallization. As a result, the rSIM decreases. Upon a cold-rolling and annealing at 623 K for30 min, the Ti50Ni48Fe2 alloy exhibits excellent superelasticity with the maximum recoverable strain of 5.8 % at a loading strain of 7 %. In such a case, a complete superelasticity of 5 % can be obtained in the Ti50Ni48Fe2 alloy after deformation increasing to 15 cycles.

关键词： Shape memory alloys Cold-rolling Annealing Superelasticity

Recent advances in morphology control of platinum catalysts toward oxygen reduction reaction

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Frontiers in Energy 2024年第3期18卷 330-355页

作者： shun CHEN Yanru liu Xiaogang fu Wanglei WANG State Key Laboratory of Solidification Processing Atomic Control and Catalysis Engineering LaboratorySchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration National Clinical Research Center for Oral DiseasesShaanxi Key Laboratory of StomatologyDepartment of Dental MaterialsSchool of StomatologyThe Fourth Military Medical UniversityXi’an 710032China

Exploring advanced platinum (Pt)-based electrocatalysts is vital for the widespread implementation of proton exchange membrane fuel cells (PEMFCs). Morphology control represents an effective strategy to optimize the behavior of Pt catalysts. In this work, an attempt is made to comprehensively review the effect of morphology control on the catalytic behavior of catalysts in the oxygen reduction reaction (ORR). First, the fundamental physicochemical changes behind morphology control, including exposing more active sites, generating appropriate lattice strains, and forming different crystalline surfaces, are highlighted. Then, recently developed strategies for tuning the morphologies of electrocatalysts, including core-shell structures, hollow structures, nanocages, nanowires, and nanosheets, are comprehensively summarized. Finally, an outlook on the future development of morphology control of Pt catalysts is presented, including rational design strategies, advanced in situ characterization techniques, novel artificial intelligence, and mechanical learning. This work is intended to provide valuable insights into designing the morphology and technological innovation of efficient redox electrocatalysts in fuel cells.

关键词： morphology platinum catalysts electrocatalysis ORR PEMFC

Strain engineering of Pt-based electrocatalysts for oxygen reaction reduction

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Frontiers in Energy 2024年第2期18卷 241-262页

作者： Zeyu WANG Yanru liu shun CHEN Yun ZHENG Xiaogang fu Yan ZHANG Wanglei WANG State Key Laboratory of Solidification Processing Atomic Control and Catalysis Engineering LaboratorySchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration National Clinical Research Center for Oral DiseasesShaanxi Key Laboratory of StomatologyDepartment of Dental MaterialsSchool of StomatologyThe Fourth Military Medical UniversityXi’an 710032China Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China Key Laboratory of Marine Chemistry Theory and Technology(Ministry of Education) College of Chemistry and Chemical EngineeringOcean University of ChinaQingdao 266100China

Proton exchange membrane fuel cells(PEMFCs)are playing irreplaceable roles in the construction of the future sustainable energy ***,the insufficient performance of platinum(Pt)-based electrocatalysts for oxygen reduction reaction(ORR)hinders the overall efficiency of *** the surface strain of catalysts is considered an effective way to tune their electronic structures and therefore optimize catalytic *** this paper,insights into strain engineering for improving Pt-based catalysts toward ORR are elaborated in ***,recent advances in understanding the strain effects on ORR catalysts are comprehensively ***,strain engineering methodologies for adjusting Ptbased catalysts are comprehensively ***,further information on the various challenges and potential prospects for strain modulation of Pt-based catalysts is provided.

关键词： strain engineering Pt-based catalysts oxygen reduction reaction(ORR) catalytic performance proton exchange membrane fuel cells(PEMFCs)

Analytical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

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Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang Shen Ying-shun Zhu fu-San Chen China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China Institute of High Energy Physics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design

Effect of heat treatment on corrosion behaviors of Mg-6Gd-3Y-0.5Zr alloy

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China Foundry 2024年第5期21卷 599-612页

作者： Fei Wang Bin-guo fu Yu-feng Wang Tian-shun Dong Guo-lu Li Jin-hai liu Hebei Key Laboratory of New functional Materials School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China Tianjin Institute of Aerospace Mechanical and Electrical Equipment Tianjin 300301China Tianjin Aerospace Long March Technology and Equipment Co. Ltd.Tianjin 300462China

The microstructures and corrosion behaviors of as-cast,T4-treated,and T6-treated Mg-6Gd-3Y-0.5Zr alloys were systematically investigated by SEM,TEM,immersion test,and electrochemical corrosion *** results show that the microstructure of the as-cast alloy is composed ofα-Mg and Mg_(24)(Gd,Y)_(5)eutectic phase,and in T4-treated alloy,Mg_(24)(Gd,Y)_(5)phase dissolves into theα-Mg matrix,leading to an increase in the(Y,Gd)H_(2)*** T6 treatment,nanoscale Mg_(24)(Gd,Y)_(5)phase dispersedly precipitates from theα-Mg matrix,and exhibits a specific orientation relationship with theα-Mg:(332)Mg_((24)(Gd,Y)_(5))//(1011)_(α-Mg),[136]Mg_((24)(Gd,Y)_(5))//[1210]_(α-Mg).The corrosion resistance of the Mg-6Gd-3Y-0.5Zr alloys can be ranked in the following order:T6-treated alloy exhibits the highest corrosion resistance,followed by the T4-treated alloy,and finally,the as-cast *** corrosion products of the alloys are all composed of MgO,Mg(OH)_(2),Gd_(2)O_(3),Y_(2)O_(3),and MgCl_(2).The corrosion behavior of Mg-6Gd-3Y-0.5Zr alloy is closely related to the precipitated *** establishing the relationship between corrosion rate,hydrogen evolution rate,and corrosion potential,it is further demonstrated that during the micro galvanic corrosion process,the coarse Mg_(24)(Gd,Y)_(5)phase in the as-cast alloy undergoes extensive dissolution,and(Y,Gd)H_(2)phase promotes the dissolution of theα-Mg matrix in the T4-treated alloy,intensifying the hydrogen evolution *** T6-treated alloy,with dispersive precipitation of nanoscale Mg_(24)(Gd,Y)_(5)phase,exhibits better corrosion resistance performance.

关键词： Mg-6Gd-3Y-0.5Zr alloy heat treatment microstructure precipitated phase corrosion resistance