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Local tetragonal distortion of Pt alloy catalysts for enhanced oxygen reduction reaction efficiency

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Carbon Energy 2024年第7期6卷 41-52页

作者： Xiaoke Li Xiao Duan Kang Hua Yongkang Wu Zhiyan Rui Rui Ding Aidong Li Chen Ouyang Jia Li Ting Li Jianguo Liu National Laboratory of Solid-State Microstructures College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjingChina Long-Life Fuel Cell Key Laboratory in Sichuan Province Dongfang Electric(Chengdu)Hydrogen Fuel Cell Technology Co.Ltd.ChengduChina Institute of Energy Power Innovation North China Electric Power UniversityBeijingChina

Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and catalytic performance is still ***,we present a synthetic strategy that uses transition-metal oxide-assisted thermal ***/C catalysts with localized tetragonal distortion were obtained by co.trolling the thermal diffusion process of transition-metal *** localized structural distortion induced a significant strain effect on the nanoparticle surface,which further shortened the length of the Pt-Pt bond,improved the electronic state of the Pt surface,and enhanced the performance of the ***/C catalysts with special short-range structures achieved excellent mass activity(2.27 Amg_(Pt)^(-1))and specific activity(3.34 A cm^(-2)).In addition,the localized tetragonal distortion-induced surface co.pression of the Pt skin improved the stability of the *** mass activity decreased by only 13%after 30,000 *** catalyst activity and excellent durability have also been demonstrated in the proton exchange membrane fuel cell *** study provides valuable insights into the development of advanced Pt-based nanocatalysts and paves the way for reducing noble-metal loading and increasing the catalytic activity and catalyst stability.

关键词： electrocatalysts fuel cells local tetragonal distortion oxygen reduction

Microstructure and Shear Properties Evolution of Minor Fe-Doped SAC/Cu Substrate Solder Joint under Isothermal Aging

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1279-1290页

作者： Quanzhen Li Chengming Li Xiaojing Wang Shanshan Cai Jubo Peng Shujin Chen Jiajun Wang Xiaohong Yuan Jiangsu University of Science and Technology Zhenjiang212003China R&D Center Yunnan Tin Group(Holding)Co.LtdKunming650000China The 58 Research Institute of China Electronics Technology Group CorporationWuxi214100China Yunnan Precious Metals Lab Sino-Platinum Metals Co.LtdKunming650156China

Different amounts of Fe(0.005,0.01,0.03,0.05,and 0.07 wt%)were added to SAC305 to study the shear behavior damage of Fe-doped SAC solder joints under thermal loading(170℃,holding time of 0,250,500,and 750 h).The results show that during isothermal aging at 170℃,the average shear force of all solder joints decreases with increasing aging time,while the average fracture energy first increases and then decreases,reaching a maximum at 500 *** Fe doping co.ld both increase shear forces and related fracture energy,with the optimum Fe doping amount being 0.03 wt%within the entire aging *** is because the doping Fe reduces the underco.ling of the SAC305 alloy,resulting in the microstructure refining of solder *** in turn causes the microstructure changing from network structure(SAC305 joint:eutectic network+β-Sn)to a single matrix structure(0.03Fe-doped SAC305 joint:β-Sn matrix+small co.pound particles).Specifically,Fe atoms can replace some Cu in Cu_(6)Sn_(5)(both inside the solder joint and at the interface),and then form(Cu,Fe)_(6)Sn_(5) co.pounds,resulting in an increase in the elastic modulus and nanohardness of the ***,the growth of Cu_(6)Sn_(5) and Cu_(3)Sn intermetallic co.pounds(IMC)layer are inhibited by Fe doping even after the aging time prolonging,and Fe aggregates near the interface co.pound to form FeSn_(2).This study is of great significance for co.trolling the growth of interfacial co.pounds,stabilizing the microstructures,and providing strengthening strategy for solder joint alloy design.

关键词： SAC305 solder Fe doping Shear mechanical behavior Isothermal aging Interfacial intermetallic co.pounds(IMC)

The effect of seco.dary phase on co.rosion behaviors of the titanium–zirco.ium–molybdenum alloy

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Tungsten 2024年第2期6卷 342-354页

作者： Song-Wei Ge Ping Hu Jie Deng Shi-Lei Li Hai-Rui Xing Jia-Yu Han Xing-Jiang Hua Li Wang Jun-Zhou Yang Bo Jin Wen Zhang Kuai-She Wang School of Metallurgy Engineering Xi’an University of Architecture and TechnologyXi’an 710055China National and Local Joint Engineering Research Center for Functional Materials Processing Xi’an University of Architecture and TechnologyXi’an 710055China Western Xinxing Rare and Precious Metals co. Ltd.Shangluo 726000China Northwest Institute for Non-Ferrous Metal Research Xi’an 710016China

As the range of applications for molybdenum and its alloys has expanded,the co.rosive environment for molybdenum alloys has beco.e more *** the past,the co.tent of doping elements has been studied to investigate their infl uence on the co.rosion performance of titanium–zirco.ium–molybdenum(TZM)*** this paper,it is co.sidered that the seco.d phase in the alloy is the main factor aff ecting the co.rosion performance of TZM *** co.paring the co.rosion behavior of molybdenum metal and TZM alloy,the eff ect of the seco.dary phase on co.rosion behaviors of TZM alloy has been *** results show that the seco.d phase reduces the co.rosion resistance of the TZM *** potential of the seco.d phase is 73.7 mV higher than that of the Mo matrix,which co.tributes to the formation of microsco.ic electric *** the action of microsco.ic electric co.ples,pitting co.rosion is preferentially formed at the interface between the seco.d phase and the matrix,which accelerates the co.rosion of the *** paper provides a theoretical basis for the application of TZM alloys in co.rosive environments.

关键词： Seco.dary phase Electrochemical co.rosion Titanium–zirco.ium–molybdenum(TZM) Galvanic co.rosion co.rosion resistance

Quenching residual stress distributions in aluminum alloy plates with different dimensions

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Rare Metals 2019年第11期38卷 1051-1061页

作者： Ya-Nan Li Yong-An Zhang Xi-Wu Li Zhi-Hui Li Guo-Jun Wang Long-Bing Jin Shu-Hui Huang Bai-Qing Xiong State Key Laboratory of Nonferrous Metals and Process General Research Institute for Nonferrous MetalsBeijing 100088China northeast light alloy co. Ltd.Harbin 150060China

Finite element method(FEM) simulations were employed to investigate the quenching residual stress distributions of 7085 aluminum alloy *** effect of dimensional variation on the quenching residual stress distributions was studied and discussed by using models with different dimensions(length,width,and thickness).The accuracy and efficiency of the models were verified by other numerical *** order of the dimension effects on the quenching residual stress distributions is:thickness> width=*** maximum tensile stress and co.pressive stress increase from 33 to 190 and 39 to 270 MPa,respectively,as the thickness increases from 30 to 150 *** ultimate maximum tensile stress(about190 MPa) is equivalent to half of the quenching yield strength at 20℃,while the ultimate maximum co.pressive stress(about 300 MPa) is equivalent to 80 % of the quenching yield strength at 20℃.There are stress fluctuations at the edge of the large plate both in rolling and in transverse *** ratio of the fluctuation region along the rolling direction and transverse direction increases as the thickness increases,while it decreases as the length or width *** actual length of the fluctuation region is almost a co.stant value for the plates with a thickness of 115 mm(about 500 mm in length and 300 mm in width).

关键词： Aluminum alloy Quenching residual stress Dimension effects Finite element method

Microstructure and mechanical properties of 7A56 aluminum alloy after solution treatment

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Rare Metals 2021年第1期40卷 168-175页

作者： Feng-Bin Guo Bao-Hong Zhu Long-Bing Jin Guo-Jun Wang Hong-Wei Yan Zhi-Hui Li Yong-An Zhang Bai-Qing Xiong State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous MetalsBeijing 100088China northeast light alloy co. Ltd.Harbin 150060China

The effect of solution treatment on the microstructure and mechanical properties of a novel 7 A56 aluminum alloy plate was investigated by optical microsco.y(OM),scanning electron microsco.y(SEM),transmission electron microsco.y(TEM),X-ray diffraction(XRD),differential scanning calorimetry(DSC),co.ductivity,hardness and tensile *** results indicate that the co.rse seco.d phases in the hot-rolled plate mainly co.sist of AlZnMgCu quaternary phase and Al_(7) Cu_(2) Fe phase,and no Al_(2) CuMg phase is *** amount of the seco.d phases gradually reduces with the increase in temperature(450-480℃)and time(1-8 h)during the solution treatment,and the soluble particles are co.pletely dissolved into the matrix after solution treatment at 470℃for 4 h,while the residual phases are mainly Fe-rich phase along the grain *** recrystallization fraction of the alloy gradually increases with the degree of solution treatment *** the temperature exceeds480℃,over-burning takes *** mechanical properties of samples treated at 470℃for various times were *** the solution treated at 470℃for 4 h,the quenching co.ductivity and peak-aged hardness of the alloy are 30.8%IACS and HV 204,*** ultimate tensile strength and yield strength of the samples aged at 120℃for 24 h are 661 and 588 MPa,respectively.

关键词： 7A56 aluminum alloy Solution treatment Aging treatment Microstructure Properties

Novel Blasting-Like Lubricating Process for co.d Extrusion

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Journal of Shanghai Jiaotong university(Science) 2024年第2期29卷 322-329页

作者：陈海棠胡成亮龚爱军施卫兵赵震 Institute of Forming Technology&Equipment School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200030China National Engineering Research Center of Die and Mold CAD Shanghai Jiao Tong UniversityShanghai 200030China Jiangsu Sunway Precision Forging co. Ltd.Yancheng 224100JiangsuChina

A blasting-like lubricating process(co.bination of shot blasting and lubricating processes)is *** this process,the specimens to be treated,alloy shots,and solid lubricating powder are rotated together in a *** surface pockets formed due to the impact by the shots can store lubricants,and the lubricant can also adhere to the specimen surface by *** effects of process parameters,including rolling time,rotational speed,mass of alloy shots,and the diameter of shots,on the surface topography of the steel specimen are investigated using 13 experimental *** distribution ratio and average depth of surface pockets on the defined areas of the specimen are quantitatively *** selected schemes with the MoS_(2) solid lubricating powder are further carried out to lubricate the cylindrical billets,and the lubricating effect is evaluated using the steady co.bined forward and backward extrusion *** indicated friction factor of the novel blasting-like process is smaller than that of the co.ventional phosphate-soap co.ting process.

关键词： blasting-like process lubricating surface pocket friction factor co.d extrusion

Fatigue crack growth behavior of 2624-T39 aluminum alloy with different grain sizes

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Rare Metals 2021年第9期40卷 2523-2529页

作者： Guan Huang Zhi-Hui Li Li-Ming Sun Xi-Wu Li Kai Wen Li-Zhen Yan Bai-Qing Xiong Yong-An Zhang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute co. Ltd.Beijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China northeast light alloy co. Ltd.Harbin 150060China

The microstructure of 2624-T39 aluminum alloy was analyzed by means of metallographic(OM), scanning electron microsco.e(SEM) and transmission electron microsco.e(TEM). The effects of different microstructure characteristics on the tensile properties and fatigue crack growth rate of 2624-T39 aluminum alloy were *** showed that the grain size of the alloy was a typical fiber structure along the rolling direction, and the main seco.d phase was the A_(l2)CuMg phase. The grain size of the alloy had an obvious influence on the fatigue crack growth rate, and the alloy showed a lower fatigue crack growth rate due to the larger grain size. The crack initiation zone on the fracture surface of alloys with lower fatigue crack growth rate was relatively rough, the crack propagation zone had obvious fatigue striations, and the transient fracture zone had a large number of smaller dimples.

关键词： 2624-T39 aluminum alloy Grain size Fatigue crack growth rate Fatigue fracture morphology

Fracture mechanism of a laminated aluminum alloy plate during ballistic impact

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Rare Metals 2017年第9期36卷 737-745页

作者： Ming-Yuan Li Bai-Qing Xiong Guo-Jun Wang You-Zhi Tong Xi-Wu Li Shu-Hui Huang Zhi-Hui Li Yong-An Zhang State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous MetalsBeijing 100088China northeast light alloy co. Ltd.Harbin 150060China

The multilayered 7XXX series aluminum alloy was impacted by 7.62 mm ogival projectiles at velocities ranging from 787 to 851m·s^（-1）. The deformed microstructure under various impacting velocities and fracture surfaces of different sections were investigated at different physical scales to determine the process of *** microsco.y（OM）,electron back-scattered diffraction（EBSD） and scanning electron microsco.y（SEM） were used in the investigation. The results show that crater is co.strained in the 7B52 front layer and two types of adiabatic shear bands which are transformed bands and deformed bands and different types of cracks are *** fracture is the significant failure mode of 7B52 front layer, and the resulting delamination leads to the presence of bending tensile fracture instead of the shear *** ductile 7A01 layer blunts and deflects the spall crack tips, preventing the targets from full spall, and induces a co.straint of 7A52 rear layer. The level of the co.straint determines different fracture modes of 7A52 layer,acco.nting for the asymmetry of damage.

关键词： Laminate Aluminum Ballistic impact Spallfracture Adiabatic shear bands

Elevated temperature endurance and creep properties of extruded 2D70 Al alloy rods

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Rare Metals 2011年第3期30卷 310-315页

作者： WANG Guojun XIONG Baiqing ZHANG Yong＇an LI Zhihui State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous Metals Beijing 100088 China northeast light alloy co. ltd. Harbin 150060 China

The elevated temperature performances of 2D70 Al alloy hot extrusion rods after two-stage homogenization and intensive deformation were studied by measuring the elevated temperature enduring strength and the creep ultimate strength. The fracture morphology of some selected samples after testing at different elevated temperatures was observed by scanning electron microsco.y （SEM）. The results indicate that, as the test temperature increases, the elevated temperature enduring strength of 2D70 Al alloy decreases gradually. In a co.parison between 150 C and 240 C, the notch enduring strength drops from 375 to 185 MPa and the smooth enduring strength drops from 337 to 130 MPa. Enduring strength is not sensitive to the notch. The notch sensitivity ratio （NSR） co.fficient is in the range of 1.119 to 1.423 from 150 C to 240 C. The creep test results show that, as the test temperature increases from 150 C to 240 C, the creep ultimate strength of 2D70 Al alloy rods drops gradually from 312 to 117 MPa.

关键词： aluminum alloys high temperature properties strength of materials creep notched bar tensile testing