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Growth Characteristics and Reinforcing Behavior of In-situ NbCp in Laser Cladded Fe-based Composite Coating

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Journal of Materials Science & Technology 2015年第7期31卷 766-772页

作者： Qingtang Li yongping lei Hanguang Fu School of Materials Science and Engineering Beijing University of Technology

Over the past decade, researchers demonstrated much interest in laser cladded metal matrix composite coatings for its good wear resistance. In this paper, in-situ NbCp reinforced Fe-based wear-resistance coatings with different designed NbC contents were produced by laser cladding. The formation mech- anism of NbC particle was analyzed. The effects of NbC content on the microstructure and mechanical properties of coatings were investigated. It was revealed that α-（Fe, Cr）, （Fe, Cr）7C3, NbC existed in all coatings. NbC particles formed by the chemical reaction of Nb and C dissolved in the molten pool. The increase of designed NbC content led to the growth of the porosity amount, and the increase of the size and the area ratio of the particle, as well as the transformation of the NbCp morphology from quadrangle to petaloid shape. Moreover, the micro-hardness and the wear resistance of the coating were improved with the increase of NbC. When NbCp content was 30 wt%, the mechanical properties decreased slightly. Copyright @ 2015, The editorial office of Journal of Materials Science ＆ Technology. Published by Elsevier

关键词： Laser claddingln-situNbC particleFormation mechanismMechanical property

Numerical Analysis of Two-Way Interaction between Weld-Pool and Arc for GTA Welding Process

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Journal of Materials Science & Technology 2001年第1期17卷 171-172页

作者： yongping lei Xianghua GU Yaowu SHI Welding Research Insttute School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China Beijing Polytechnic University

A mathematical model to describe the heat transfer and fluid flow in the mutually coupled weld pool and arc by an interactive free surface of the pool for a stationary gas tungsten arc welding (GTAW) is developed. The two sets of governing equations and auxiliary formulas, controlling the weld pool and plasma arc systems respectively, were solved by a finite difFerence method. A boundary-fitted coordinate system was adopted because the free surface has a curved and unknown shape during welding. The results of this work provide a fundamental basis for predicting the behavior of an integrated' weld pool and arc system from first principles.

关键词： TUNGSTEN

Fracture Assessment for Electron Beam Welded Damage Tolerant Ti-6Al-4V Alloy by the FITNET Procedure

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Chinese Journal of Mechanical Engineering 2013年第5期26卷 1013-1021页

作者： LU Wei SHI Yaowu LI Xiaoyan lei yongping College of Materials Science and Engineering Beijing University of Technology

Fracture assessment of the cracked structures is essential to avoiding fracture failure.A number of fracture assessment procedures have been proposed for various steel ***,the studies about the application of available procedures for titanium alloy structures are scarcely *** assessment for the electron beam(EB) welded thick-walled damage tolerant Ti-6Al-4V(TC4-DT) alloy is performed by the fitness-for-service(FFS) FITNET *** tensile tests and fracture assessment tests of the base metal and weld metal are carried out to obtain the input information of *** standard options and advanced options of FITNET FFS procedure are used to the fracture assessment of the present ***,the predicted maximum loads of compact tensile specimen using FITNET FFS procedure are verified with the experimental data of fracture assessment *** a result,it is shown that the mechanical properties of weld metal are inhomogeneous along the weld *** mismatch ratio M is less than 10% at the weld top and middle,whereas more than 10% at the weld *** assessment lines of standard options are close to that of advanced option,which means that the standard options are suitable for fracture assessment of the present *** accurate estimation of the maximum loads has been obtained by fracture assessment of standard options with error less than 6%.Furthermore,there are no potential advantages of applying higher options or mismatch ***,the present welded joints can be treated as homogeneous material during the fracture assessment,and standard option 1 can be used to achieve accurate enough *** research provides the engineering treatment methods for the fracture assessment of titanium alloy and its EB welds.

关键词： FITNET FFS procedure fracture assessment analysis electron beam welding thick-walled plates titanium alloy

Limit Load Solution for Electron Beam Welded Joints with Single Edge Weld Center Crack in Tension

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Chinese Journal of Mechanical Engineering 2012年第3期25卷 624-628页

作者： LU Wei SHI Yaowu LI Xiaoyan lei yongping College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

Limit loads are widely studied and several limit load solutions are proposed to some typical geometry of ***,there are no limit load solutions exist for the single edge crack weldments in tension（SEC（T））,which is also a typical geometry in fracture *** mis-matching limit load for thick plate with SEC（T） are investigated and the special limit load solutions are proposed based on the available mis-matching limit load solutions and systematic finite element *** real weld configurations are simplified as a strip,and different weld strength mis-matching ratio M,crack depth/width ratio a/W and weld width 2H are in *** a result,it is found that there exists excellent agreement between the limit load solutions and the FE results for almost all the mis-matching ration M,a/W and ligament-to-weld width ratio（W-a）/***,useful recommendations are given for evaluating the limit loads of the EBW structure with SEC（T）.For the EBW joints with SEC（T）,the mis-matching limit loads can be obtained assuming that the components are wholly made of base metal,when M changing from 1.6 to *** M decreasing to 0.4,the mis-matching limit loads can be obtained assuming that the components are wholly made of base metal only for large value of（W-a）/*** recommendations may be useful for evaluating the limit loads of the EBW structures with SEC（T）.The engineering simplifications are given for assessing the limit loads of electron beam welded structure with SEC（T）.

关键词： limit load single edge crack in tensile electron beam welding

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均一微滴制备技术研究进展

科技导报 2024年第18期42卷 76-90页

作者：王同举张琦美张文倩雷永平林健符寒光北华航天工业学院电子与控制工程学院廊坊065000 河北省微纳卫星协同创新中心廊坊065000 北京工业大学材料与制造学部北京100000

均一微滴的应用十分广泛,生成方法越来越高效可控。阐述了射流扰动均一微滴制备技术和按需可控均一微滴制备技术的原理。基于脉冲力形成的原理不同,均一微滴制备技术分为压电式、电磁致动式、磁流体式、气压脉冲式和激光流体共振式,总结... 详细信息

均一微滴的应用十分广泛,生成方法越来越高效可控。阐述了射流扰动均一微滴制备技术和按需可控均一微滴制备技术的原理。基于脉冲力形成的原理不同,均一微滴制备技术分为压电式、电磁致动式、磁流体式、气压脉冲式和激光流体共振式,总结了5种模式的原理和技术现状。梳理了均一微滴制备技术在电子封装领域、喷墨彩印技术领域、微型件3D打印领域和生物制药等领域的应用现状,并展望了均一微滴制备技术的发展趋势。

关键词：均一微滴射流扰动按需可控电子封装 3D打印

Environmentally friendly solders 3-4 beyond Pb-based systems

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Rare Metals 2006年第Z2期25卷 95-100页

作者： GAO Yuan LIU Peng GUO Fu XIA Zhidong lei yongping SHI Yaowu College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China

Based on environmental considerations, global economic pressures, enacted by legislations in several countries, have warranted the elimination of lead from solders used in electronic applications. Sn3.5Ag, SnAgCu, and Sn0.7Cu have emerged among various lead-free candidates as the most promising solder alloys to be utilized in microelectronic industries. However, with the vast development and miniaturization of modern electronic packaging, new requirements such as superior service capabilities have been posed on lead-free solders. In order to improve the comprehensive property of the solder alloys, two possible approaches were adopted in the current research and new materials developed were patented. One approach was involved with the addition of alloying elements to make new ternary or quaternary solder alloys. Proper addition of rare earth element such as La and Ce have rendered solder alloys with improved mechanical properties, especially creep rupture lives of their joints. Another approach, the composite approach, was developed mainly to improve the service temperature capability of the solder alloys. Composite solders fabricated by mechanically incorporating various reinforcement particles to the solder paste have again exhibited enhanced properties without altering the existing processing characteristics. The recent progress and research efforts carried out on lead-free solder materials in Beijing University of Technology were reported. The effects of rare earth addition on the microstructure, processing properties, and mechanical properties were presented. The behaviors of various Sn-3.5Ag based composite solders were also explicated in terms of the roles of reinforcement particles on intermetallic growth, steady-state creep rate, the onset of tertiary creep, as well as the overall creep deformation in the solder joints. Thermomechanical fatigue (TMF) behavior of the solder alloys and composite solders were investigated with different parameters such as ramp

关键词： lead-free solder composite solder no-clean flux creep mechanical properties thermomechanical fatigue

A study of microstructure and properties of cast Fe-10Cr-1.5B alloy

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China Foundry 2014年第3期11卷 185-190页

作者： Zhang Haibin Cen Qihong Fu Hanguang lei yongping Xing Jiandong School of Materials Science and Engineering Beijing University of Technology School of Materials Science and Engineering National Engineering Research Center of Waste Resource Recovery Kunming University of Science and Technology State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University

In the present study, the microstructure and mechanical properties of cast Fe-10Cr-1.5B（FCB） alloy after different heat treatments were studied. The results showed that the as-cast microstructure of FCB alloy consists of α-Fe, M（M=Cr, Fe, Mn）2（B, C） and M（M=Cr, Fe, Mn）7（C, B）3 type borocarbides, and small amounts of pearlite and austenite. After oil quenching treatment, metal matrix transformed into the martensite from the mixture of martensite, pearlite and austenite. There are many M（M=Cr,Fe,Mn）23（C,B）6 type borocarbide precipitates in the metal matrix, and eutectic borocarbide appears with an apparent disconnection and isolated phenomenon. When the quenching temperature reaches 1,050℃, the hardness of FCB alloy is the highest, but the change of quenching temperature has no obvious effect on impact toughness of FCB alloy. After tempering, the eutectic microstructure of FCB alloy appears with a ＂two links＂ trend. With the increase of tempering temperature, the hardness of FCB alloy decreases gradually and impact toughness increases gradually. Cast FCB alloy oil-quenched from 1,050℃ and tempered from 200℃ has excellent combined properties; its hardness and impact toughness are 61.5 HRC and 8.8 J·cm^-2 respectively.

关键词： Fe-Cr-B alloy solidification microstructure heat treatment mechanical property

锆合金管塞结构压力电阻焊接头的应力集中系数及影响因素

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机械工程材料 2024年第2期48卷 82-88页

作者：季顺成张学粮林健(导师) 鲁立陈兵兵雷永平冯刚北京工业大学材料与制造学部北京100124 中广核铀业发展有限公司北京100029 苏州热工研究院有限公司苏州215004

采用Abaqus有限元分析软件建立了锆合金管塞结构压力电阻焊接模型与应力集中系数计算模型,通过与热模拟试验得到的挤出金属高度进行对比,对焊接模型进行验证,模拟分析了内部挤出金属过渡角、端塞行进量和包壳管内壁倒角对接头应力集中... 详细信息

采用Abaqus有限元分析软件建立了锆合金管塞结构压力电阻焊接模型与应力集中系数计算模型,通过与热模拟试验得到的挤出金属高度进行对比,对焊接模型进行验证,模拟分析了内部挤出金属过渡角、端塞行进量和包壳管内壁倒角对接头应力集中系数的影响。结果表明:内部挤出金属高度模拟结果和试验结果的相对误差为9.58%,外部挤出金属高度的相对误差为6.65%,说明建立的焊接模型准确;随着内部挤出金属过渡角增加,接头应力集中系数先降低,当过渡角增大至60°后增加,增大至120°时又下降;随着端塞行进量的增加,内部挤出金属过渡角降低,应力集中系数增加,接头熔合线长度增大;与未倒角接头相比,包壳管内壁倒角深度不大于0.50 mm时应力集中系数降低,最大降低了16.00%,倒角深度大于0.50 mm时应力集中系数增大,最大提高了91.49%。

关键词：锆合金管塞结构压力电阻焊应力集中系数端塞行进量

A review of welding simulation methods for large components

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Progress in Natural Science:Materials International 2023年第5期33卷 551-568页

作者： Shuai Liu Zhiqiang Wu Wenhao Zhou Honggang Zhou Keke Zhang Danqing Yin yongping lei Yongfeng Qiu Engineering Research Center of Mining Development Technology and Equipment for Deep Sea and Earth Ministry of Education Hunan University of Science and Technology Hunan Valin Xiangtan Iron & Steel Group Co. Ltd Research Institute of Technology Jianglu Electromechanical Science & Technology Co. Ltd.Xiangtan School of Materials Science and Engineering Henan University of Science and Technology School of Materials Science and Engineering Beijing University of Technology Guiyang Aluminum Magnesium Design & Research Institute Co. Ltd

The challenges posed by cross-scale effects, large computational requirements, high nonlinearity, and complex interactions of multiple physical phenomena constitute major obstacles to the effectiveness and accuracy of welding simulations for large structural components. Therefore, achieving accurate welding simulation to predict and effectively control welding deformation of substantial engineering structural parts is essential to ensure welding quality and improve production efficiency. This paper reviews the current research status of welding numerical simulation of large engineering components, including the establishment of the finite element model,optimization of the heat source model, selection of appropriate finite element calculation method, and the control of welding deformation through optimization algorithm. In addition, the strategies to improve the precision and efficiency of welding numerical simulation and control welding deformation of engineering components are analyzed and discussed. The future development of welding numerical simulation will focus on balancing simulation accuracy and simulation efficiency and optimizing welding parameters to control welding deformation efficiently.

关键词： Large welded components Algorithm optimization Welding deformation Simulation accuracy and efficiency