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Photonics and Optoelectronics, SOPO

作者： P. Q. Xu Z. S. Yu H. Y. Gong J. P. He F. G. Lu H. C. Cui X. H. Tang College of Materials Engineering Shanghai University Engineering of Science Shanghai China Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiaotong University Shanghai China

ISBN: (纸本)9781424449637

Invar alloy has lower thermal expansion and is widely used. However, its intensity is too low to meet the requirement of industry. In order to improve its high-temperature strength, WC-Co cemented carbide was welded to invar alloy using high energy laser-TIG (Tungsten Inert Gas) hybrid welding. WC migration phenomenon was discovered in welding process and its corresponding mechanism was discussed. Microstructure at different interface was discussed and the hardness profile was measured. The results showed: (1) Butt joint of WC-Co/ invar alloy manifested well penetration without any filler materials; (2) WC migration near WC-Co/ weld interface was owed to synthesis action including stirring effects of welds, intrinsic Stress, high pressure of molten materials and ionized shielding gas, interface reaction and surface tension.

关键词： Welding Gas lasers Optical wavelength conversion Joining materials Thermal expansion Tungsten Microstructure Optical materials Stress Surface tension

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Isothermal transformation kinetics of X12CrMoWVNbN10-1-1 steel for the ultra-supercritical rotor

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Cailiao Rechuli Xuebao/Transactions of materials and Heat Treatment 2010年第1期31卷 35-39页

作者： Han, Li-Zhan Gu, Jian-Feng Pan, Jian-Sheng Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and Engineering Shanghai Jiaotong University Shanghai 200240 China

The isothermal transformation kinetics curves of X12CrMoWVNbN10-1-1 ferritic heat-resistant steel were investigated. The continuous heating transformation curve (CHT) tested by dilatometric experiment is converted to isothermal heating phase transformation curve (IHT) based on the relationship between isothermal transformation kinetics and continuous transformation kinetics. The transformed volume fraction of ferrite to austenite in the steel after austenization at 1070 °C for 12 h is measured as a function of isothermal time at different isothermal temperatures by quantitative metallographic *** coefficients of modified Avrami equation are obtained and TTT curve of the steel is developed based on the experiments.

关键词： Austenite

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Microstructure and Wear Behavior of FeBSiNbCr Metallic Glass Coatings

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Journal of materials Science & Technology 2009年第5期25卷 687-690页

作者： Jiangbo Cheng Xiubing Liang Binshi Xu Yixiong Wu National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China Shanghai Key laboratory of Materials Laser Processing and Modification Shanghai Jiaotong University Shanghai 200240 China

In this paper, FeBSiNbCr metallic glass coatings were prepared onto AISI 1045 steel substrate by using wire arc spraying process. The phase and structure of the coating were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD） and scanning election microscopy （SEM） equipped with energy dispersive X-ray analysis （EDX）. The microstructure of the coating consists of full amorphous phase. The coating has high hardness and low porosity. Full density and little oxides are detected in the coating. The mechanical properties, especially wear resistance, were investigated. The relationship between wear behavior and structure of the coatings were analyzed in detail. The main failure mechanism of the metallic glass coating is brittle breaking and fracture. The results indicate that FeBSiNbCr metallic glass coating has excellent resistance to abrasive wear.

关键词： Metallic glass Coatings Microstructure Wear resistance

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Stability analysis of electrical signal in O2 flux-cored double wire GMAW

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shanghai Jiaotong Daxue Xuebao/Journal of shanghai Jiaotong University 2010年第4期44卷 457-462页

作者： Wang, Fei Hua, Xue-Ming Ma, Xiao-Li Wu, Yi-Xiong Welding Engineering Institute of Material Science and Engineering Shanghai Jiaotong University Shanghai 200240 China Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiaotong University Shanghai 200240 China State Key Laboratory of Metal Matrix Composite Shanghai Jiaotong University Shanghai 200240 China

In order to get a further understanding of the arc stability and study the regular phenomenon of arc interruption during the CO2 flux-cored double wire GMAW process, a series of experiments (arc voltage matching, welding current matching and inter-wire distance matching) were designed. Synchronous high-speed camera system was used to take a picture of arc shape and data acquisition system based on labview was used to collect current and voltage waveforms simultaneously. Then histogram was used to analyze the arc stability. The results show that decreasing the voltage of trailing arc, decreasing the current ratio between trailing arc and leading arc and increasing the inter-wire distance will enhance the leading arc stability;decreasing the current ratio between leading arc and trailing arc, decreasing the voltage of trailing arc and increasing the inter-wire distance will decrease the frequency of interruption of the trailing arc. Finally, the captured images of the arc were combined with the acquisition of current, voltage waveforms, by which the arc interruption phenomenon occurred in the welding process was analyzed.

关键词： Carbon dioxide

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Development and application of alternately timed quenching technology by water and air 17

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17th International Federation for Heat Treatment and Surface Engineering Congress 2008, IFHTSE 2008

作者： Chen, Nailu Zhang, Weimin Gu, Jianfeng Zuo, Xunwei Xu, Jun Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China

ISBN: (纸本)9780000000002

Water and air are commonly being used as quenching media with large difference in quenching ability and they are environmentally friendly and of very low cost. Theoretically, the quenching alternatively by them can bring in any desirable cooling rate between those by each alone. However, such a technology has not been practicable so far due to the difficulty in processing design and control level. Recently, the development of numerical simulation and processing control techniques has established a solid base for its industrial application. In order to solve the problems that mechanical properties of medium carbon alloy steel are inferior to the requirements after oil quenching and cracking occurs after water quenching, a new technology named Alternately Timed Quenching Technology by Water and Air (AT-Quenching) is proposed in this paper. The key points are to design the process by computer simulation and to realize it with digitally controlled quenching equipments. This has been successfully used in practical production of large forged blocks of plastic die, long shaft forgings and the forgings for marine crankshaft, having effectively solved the difficulties that traditional processes and other quenchants can't.

关键词： Quenching

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Mechanical property and microstructure of HSLA steel laser hybrid welded joint

Mechanical property and microstructure of HSLA steel laser h...

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作者： Ni, J.M. Li, Z.G. Cai, Y. Huang, J. Wu, Y.X. Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong University Shanghai 200240 China

For high strength low alloy steel, butt joint of 10mm thickness plate was completed by using high power laser hybrid welding with flux cored wire. Microstructure of joint was analyzed by using optical micrography. Toughness of the joint was evaluated through Charpy V-notch type impact test at -40°C. Fracture surface was observed by SEM. The morphology and composition of precipitate particles in weld metal were analyzed by TEM and EDS. The results show that: microstructure of no crack weld metal predominately contains granular bainite and acicular ferrite. The softened behavior of the Heat affected zone isn't observed from hardness values. It should be noted that the grain of weld metal contains lots of sub-grain boundaries and dispersive precipitates. Because the dispersive precipitates could pin mobile dislocation at sub-grain boundaries, the low temperature impact toughness works of weld metal observably increase.

关键词： Precipitates

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Phase selection during solidification of undercooled Ni70.2Si29.8 eutectic alloy

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Progress in Natural Science:materials International 2009年第11期19卷 1619-1624页

作者： Yiping Lu~a,Tingju Li~(a,*),Fu Yabo~a,Sun Jianbo~(a,b),Luo Dawei~a,Gencang Yang~c, Yaohe Zhou~c a laboratory of Special processing of Raw materials,key lab of materials modification by laser,Electron and Ion Beams,Ministry of Education of China, Dalian University of Technology,Dalian 116024,China b School of materials Science and Engineering,Jiamusi University,Jiamusi 154007,China c State key laboratory of Solidification processing,Northwestern Polytechnical University,Xi’an 710072,China [a]Laboratory of Special Processing of Raw Materials Key Lab of Materials Modification by Laser Electron and Ion Beams Ministry of Education of China Dalian University of Technology Dalian 116024 China [b]School of Materials Science and Engineering Jiamusi University Jiamusi 154007 China [c]State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi&#x2019 an 710072 China

High undercooling(about 392 K) was achieved in the bulk eutectic Ni70.2Si29.8alloy melt through glass fluxing combined with cyclic *** is found that the metastable phases Ni3Si2and NiSi are obtained through slow post-solidification when undercooling exceeds 240 *** metastable phases are confirmed by using the method of X-ray diffraction and differential scanning calorimetry (DSC).Based on the principle of the free energy minimum and the transient nucleation theory,the phase selection of melt is investigated with regard to the metastable phases formation in the bulk undercooled eutectic *** formation of metastable phases from undercooled Ni70.2Si29.8melts is ascribed to competitive nucleation with the undercooling,*** undercooling facilitates the preferential nucleation of metastable phases.

关键词： Undercooling Eutectic alloy Metastable phase Nucleation

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Low energy high current pulsed electron beam treatment for improving surface microstructure and properties

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IOP Conference Series: materials Science and Engineering 2010年第1期12卷

作者： J Wu N Allain-Bonasso X D Zhang J X Zou S Z Hao T Grosdider C Dong Laboratoire d'Etude des Textures et Applications aux Matériaux (LETAM UMR-CNRS 3143) Université Paul Verlaine-Metz Ile du Saulcy 57045 Metz France Key Lab of Materials Modification by Laser Ion and Electron Beams Dalian University of Technology Dalian 116024 People's Republic of China National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong University Shanghai 200240 People's Republic of China

Low energy high current pulsed electron beam (LEHCPEB) is a fairly new technique for surface modifications authorizing improvement in wear and corrosion properties as well as texture changes and hardening. This contribution highlights some microstructure modifications encountered at the surface of HCPEB treated steels and bulk metallic glasses taking into account the effects of surface melting and the effects of the induced stress.

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Detailed analysis of welding arc spectrum distribution characteristics to choose light sources of laser sensors

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Guangdianzi Jiguang/Journal of Optoelectronics laser 2009年第4期20卷 504-508页

作者： Bao, Shun-Dong Zhang, Ke Wu, Yi-Xiong Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and Engineering Shanghai Jiaotong University Shanghai 200240 China

The MIG welding, MAG welding and TIG welding arc spectra are collected through Ocean Optics HR 4000CG-UV-NiR-spectrometer, and the frequency distribution characteristics of the UV (205-380 nm), visible spectrum (380-780 nm) And infrared spectrum (780-1000 nm) are analyzed separately. It has been found that during the MIG welding, MAG welding, TIG welding arc spectra, there are 440-480 nm, 610-700 nm and 850-950 nm relatively weak strength three-band. Based on above relatively weak strength three-band, the choice of light sources of laser sensors based is achieved on above relatively weak strength three-band and an adjustable double-reflector laser sensor is designed, and the high-quality weld groove clear images are obtained.

关键词： Light sources

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Development and application of alternate timed quenching by water and air

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International Heat Treatment and Surface Engineering 2008年第3-4期2卷 109-115页

作者： Chen, N.L. Zhang, W.M. Gu, J.F. Zuo, X.W. Xu, J. Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai 200240 China

Water and air are commonly used quench media with very different quenching powers;further, they are environmentally friendly and of very low cost. Theoretically, alternate quenching by water and air can produce any desired cooling rate between those of each medium alone. While this technology has not been practicable due to the difficulties in process design and control, the recent development of numerical simulation and processing control techniques has established a solid base for its industrial application. A new technology, alternate timed quenching by water and air (AT-quenching), is proposed. The technology has been applied to a medium carbon low alloy steel, the mechanical properties of which do not meet specification after oil quenching, but which suffers cracking after water quenching. The key points are to design the process by computer simulation and to realise it with digitally controlled quenching equipment. The technology has been successfully employed in production of large forged blocks of die steel for plastics moulding, long shaft forgings and forgings for marine crankshaft, effectively solving the difficulties that traditional processes and quenchants encounter. © 2008 IHTSE Partnership Published by Maney on behalf of the Partnership.

关键词： Quenching

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