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Particles migration behavior during laser keyhole welding of ZL101/TiB_2 composites

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Acta Metallurgica Sinica(English Letters) 2012年第3期25卷 190-200页

作者： haichao cui Fenggui LU Xinhua TANG Shun YAO Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science andEngineeringShanghai Jiao Tong UniversityShanghai 200030China

Particle redistribution occurred with the flow of pool fluid in laser welding aluminum composites. In order to investigate particle migration behavior, a numerical model was established on laser welding of ZL101-TiB2 composite. TiB2 migration coupling with fluid was realized. The volume-of-fluid （VOF） method was employed to track free fluid surfaces. The travel heat source was realized utilizing the workpiece mo- tion in place of heat source motion, which made the heat load stable. Melting and evaporation enthalpy, recoil force, surface tension and buoyancy were considered in this model. Through the calculation it showed that the simulated weld cross section shape and particle distribution were in good agreement with experimental results.

关键词： Laser welding Numerical simulation Fluid flow Particle migration

Effects of Active Gases on Droplet Transfer and Weld Morphology in Pulsed-Current NG-GMAW of Mild Steel

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Chinese Journal of Mechanical Engineering 2021年第4期34卷 249-261页

作者： Guoqiang Liu Xinhua Tang Qi Xu Fenggui Lu haichao cui Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai 200240China

The current research of narrow-gap gas metal arc welding(NG-GMAW)primarily focuses on improving the sidewall fusion and avoiding the lack-of-fusion ***,the high cost and operation difficulty of the methods limit the industrial *** this study,small amount of active gases CO_(2) and O_(2) were added into pure argon inert shielding gas to improve the weld formation of pulsed-current narrow-gap gas metal arc welding(NG-GMAW)of mild *** effects on droplet transfer and arc behavior were investigated.A high-speed visual sensing system was utilized to observe the metal transfer process and arc *** the proportion of CO_(2),being added into the pure argon shielding gas,changes from 5%to 25%,the metal transfer mode changes from pulsed spray streaming transfer to pulsed projected spray transfer,while it remains the pulsed spray streaming transfer when 2%to 10%O_(2) is *** CO2 and O_(2) are favorable to stabilizing arc and welding process.O_(2) is even more effective than CO_(2).However,O_(2) is more likely to cause slags on the weld surface,while CO_(2) can improve the weld appearance in some *** weld surface concavity in NG-GMAW is greatly influenced by the addition of active gas,but the weld width and weld penetration almost keep *** study proposes a new method which is beneficial to improving the weld bead formation and welding process stability.

关键词： Metal transfer Active gases Pulsed-current NG-GMAW Weld morphology

Effect of Trace Element on Microstructure and Fracture Toughness of Weld Metal

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Acta Metallurgica Sinica(English Letters) 2020年第3期33卷 425-436页

作者： Ke Xu Tao Fang Longfei Zhao haichao cui Fenggui Lu Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The microstructure and fracture toughness of weld metal under Ti-free and Ti-containing different fluxes were investigated in this *** was found that the trace element Ti of flux in submerged arc welding produced significant influence on the fracture *** addition of 60 ppm Ti induced the sharp increase in J0.2 value from 232.78 to 364.08 kJ/m^*** characterization revealed that a large number of oxide inclusions prompted the nucleation of acicular ferrites and refined grains,which improved the fracture toughness of Ti-containing weld metal ***,the crack propagation path was more tortuous and bifurcated due to the small amount of carbide precipitations along grain boundaries and blocky martensite-austenite islands for Ti-containing weld ***,the large-angle grain boundaries caused crack deflection and increased the resistance of crack propagation compared to Ti-free weld metal.

关键词： Fracture toughness Microstructure Weld metal Trace element Crack propagation

Effect of Carbon Migration on Interface Fatigue Crack Growth Behavior in 9Cr/CrMoV Dissimilar Welded Joint

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Acta Metallurgica Sinica(English Letters) 2022年第5期35卷 714-726页

作者： Qi Wang Chendong Shao haichao cui Yuan Gao Fenggui Lu Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China

Fatigue crack growth(FCG)behavior of 9 Cr/CrMoV dissimilar welded joint at elevated temperature and different stress ratios was *** was paid to the region near the fusion line of 9 Cr where carbon-enriched zone(CEZ)and carbon-depleted zone(CDZ)formed due to carbon migration during the welding *** and brittle tempered martensite dominated the stress ratio-insensitive FCG behavior in the coarse grain zone(CGZ)of 9 *** crack near the CGZ-CEZ interface,crack deflection through the CEZ and into the CDZ was observed,accompanied by an accelerating FCG *** with the severe plastic deformation near the secondary crack in 9 Cr-CGZ,the electron back-scattered diffraction analysis showed less deformation and lower resistance in the direction toward the brittle CEZ,which resulted in the transverse *** spite of the plastic feature in CDZ revealed by fracture morphology,the less carbides due to carbon migration led to lower strength and weaker FCG resistance property in this *** conclusion,the plasticity deterioration in CEZ and strength loss in CDZ accounted for the FCG path deflection and FCG rate acceleration,respectively,which aggravated the worst FCG resistance property of 9 Cr-HAZ in the dissimilar welded joint.

关键词： Fatigue crack growth Dissimilar welded joint Carbon migration Crack transverse deflection Carbonenriched zone

Influence Mechanism of Process Parameters on Keyhole-induced Porosity Formation Based on 3D Transient Modelling

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Influence Mechanism of Process Parameters on Keyhole-induced...

2014年全国计算机辅助焊接工程学术研讨会

作者： Fenggui Lu haichao cui Xibin Li Zhuguo Li Xinhua Tang Yixiong Wu Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and Engineering Shanghai Jiao Tong University

Keyhole-induced porosity occurring in laser weld with deep-penetration becomes a big issue in laser manufacturing the components with heavy section. In order to better insight into the keyhole-induced porosity formation process and its influencing factors, a there dimension(3 D) transient model is proposed to investigate the correlations between keyhole and porosity at different process parameters. Fluid flow, bubble movement and solidification are coupling considered in this model. Results indicate that the number of bubbles is mainly determined by keyhole stability. The keyhole easily tends to close and collapse during laser welding as increasing laser power, decreasing velocity and beam diameter, which contribute to violent flow, strong evaporation of molten pool negatively acting on the keyhole with large ratio of depth to width. However, the evolution efficiency from bubbles to porosities depends on solidification rate and temperature gradient, most of bubbles adjacent to fusion line transfer into porosities due to high solidification rate. A good agreement is obtained between the simulations and experiments.

关键词： keyhole-induced porosity process parameters evolution efficiency

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碳纤维复合材料损伤高频脉冲激光去除技术

中国表面工程 2019年第6期32卷 122-131页

作者：巴德玛熊玉成李长青崔海超陆军装甲兵学院装备保障与再制造系北京100072 中国人民解放军32178部队北京100012 中航工业复合材料技术中心北京101300

采用高频脉冲紫外激光(λ=355 nm)对碳纤维/环氧树脂基复合材料进行逐层剥蚀加工,运用响应曲面法分析了激光功率、扫描速度、光斑填充间距3个因素与剥蚀深度的交互性。使用扫描电子显微镜、三维形貌仪、接触角测量仪、X射线光电子能谱仪... 详细信息

采用高频脉冲紫外激光(λ=355 nm)对碳纤维/环氧树脂基复合材料进行逐层剥蚀加工,运用响应曲面法分析了激光功率、扫描速度、光斑填充间距3个因素与剥蚀深度的交互性。使用扫描电子显微镜、三维形貌仪、接触角测量仪、X射线光电子能谱仪,对试样表面的显微组织和理化性能进行分析,并对不同表面处理后试样界面剪切强度进行研究。结果表明:当激光参数P=13 W,d=0.02 mm,v=1000 mm/s时,激光加工形貌较好,剥蚀深度h=389μm;与砂纸打磨相比,使用紫外激光对材料进行逐层剥蚀时,不会对碳纤维骨架造成损伤;紫外激光剥蚀后的试样表面粗糙度比原始表面提高了7.9倍左右,高出不同砂纸打磨后的试样表面粗糙度约2.4~4.4倍;使用紫外激光剥蚀后的材料表面活性提高,含氧官能团数量增加;激光剥蚀处理后界面剪切强度明显增大,与砂纸打磨及未处理表面相比分别提高了48.5%和17.9%。

关键词：激光剥蚀响应曲面微观形貌理化性能剪切强度

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原位生成铝基复合材料的激光焊接

焊接学报 2010年第8期31卷 68-72页

作者：崔海超芦凤桂唐新华姚舜上海交通大学上海市激光制造与材料改性重点实验室上海200240

采用大功率激光器研究新型铝基复合材料TiB2/ZL101的焊接性能,TiB2粒子的存在增加了焊缝熔池粘度降低了熔池流动性,影响了焊缝成形,增加了气孔敏感性.焊缝中气孔主要来源于氢和复合材料中的残留盐.激光焊接过程中较大的冷却速度使得焊... 详细信息

采用大功率激光器研究新型铝基复合材料TiB2/ZL101的焊接性能,TiB2粒子的存在增加了焊缝熔池粘度降低了熔池流动性,影响了焊缝成形,增加了气孔敏感性.焊缝中气孔主要来源于氢和复合材料中的残留盐.激光焊接过程中较大的冷却速度使得焊缝晶粒非常细小,TiB2粒子在焊缝中分布更均匀,没有出现粒子偏析,主要是因为TiB2粒子是属于纳米级,在凝固过程中被凝固界面前沿所捕获而没有被推移.TiB2粒子没有与铝基体发生界面反应生成脆性相Al3Ti及AlB2,TiB2粒子与Al基体界面结合较好.结果表明,激光焊接后没有破坏TiB2粒子的增强效果.

关键词：复合材料激光焊接气孔界面反应增强相分布

等离子体法炭黑工艺与炉法炭黑工艺的?对比分析

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化工学报 2018年第7期69卷 2815-2821页

作者：崔海超陈仙辉王城夏维东中国科学技术大学工程科学学院安徽合肥230027 合肥碳艺科技有限责任公司安徽合肥230088

传统炭黑生产过程热能效率低,存在大量NO_x和CO_2排放,炭黑收率低。等离子体法生产炭黑能大幅提高能量利用效率,理想状况下可以完全收获原料中的碳,并消除由于燃烧产生的CO_2和NO_x排放。基于Aspen Plus软件模拟了炉法炭黑和等离子体法... 详细信息

传统炭黑生产过程热能效率低,存在大量NO_x和CO_2排放,炭黑收率低。等离子体法生产炭黑能大幅提高能量利用效率,理想状况下可以完全收获原料中的碳,并消除由于燃烧产生的CO_2和NO_x排放。基于Aspen Plus软件模拟了炉法炭黑和等离子体法炭黑工艺过程。计算分析了等离子体法炭黑工艺相对于炉法炭黑工艺的节能效果:对于炉法炭黑分别计算了N110、N220、N330、N440和N550五种炭黑品种的过程?流,等离子体法炭黑计算了甲烷和焦油两种原料的过程?流;对比分析了两种工艺过程炭黑收率、进出料?流、产品?效率以及工艺过程?效率。结果表明:以焦油为原料的炉法炭黑收率在47.6%~66.6%之间,与实际值吻合,明显低于等离子体法94%的理想炭黑收率;以焦油为原料的理论计算表明,等离子体法炭黑产品?效率和工艺过程?效率显著高于炉法炭黑;以焦油为原料的等离子体法炭黑产品?效率高于以甲烷为原料的产品?效率。

关键词：等离子体法炭黑炉法炭黑化学过程火用数值模拟

铝-钢异质金属双光束激光焊接IMC层迁移行为及对界面性能的影响

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机械工程学报 2020年第6期56卷 33-40页

作者：袁锐邓胜杰崔海超麻寕绪芦凤桂上海市激光制造与材料改性重点实验室上海200240 上海交通大学材料科学与工程学院上海200240 大阪大学结合科学研究所日本大阪567-0047

利用双光束激光熔-钎焊焊接方法开展了AA7075/DP590异质金属的连接,通过改变激光功率等焊接工艺发现熔钎焊接头显微组织中存在金属间化合物(Intermetallic compound, IMC)层脱离铝-钢界面整体迁移进入焊缝内部的特殊现象,迁移现象位于... 详细信息

利用双光束激光熔-钎焊焊接方法开展了AA7075/DP590异质金属的连接,通过改变激光功率等焊接工艺发现熔钎焊接头显微组织中存在金属间化合物(Intermetallic compound, IMC)层脱离铝-钢界面整体迁移进入焊缝内部的特殊现象,迁移现象位于激光直接作用区域,数值模拟发现激光直接作用下的熔池剧烈流动驱动了IMC的迁移。对迁移部分IMC层物相表征分析发现,近铝-钢界面处发生迁移的IMC层形貌呈致密平板状,与铝-钢界面处IMC层相似,由η相组成;迁移深入焊缝内部的IMC层内有裂纹、断裂产生,由θ相组成,裂纹处存在铝焊缝组织长入,发生迁移的IMC层内部存在η相与θ相的过渡区。拉伸结果表明,IMC层迁移现象的出现会削弱焊接接头铝-钢界面处的强度,这是因为界面初生的IMC层薄弱,止裂能力差,所以控制IMC层迁移有利于提高接头力学性能。

关键词：铝-钢异质金属双光束熔-钎焊金属间化合物(Intermetallic compound,IMC) 力学性能