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Rotating extrusion technique and its effect on quality of aluminum alloy thin-plate weldments

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Transactions of Nonferrous Metals Society of China 2010年第2期20卷 183-188页

作者：李军杨建国闫德俊张勇方洪渊 state key laboratory of advanced welding production Technology Harbin Institute of Technology

A new technique named rotating extrusion was proposed that uses rotating extrusion action to rectify residual distortion of aluminum alloy thin-plate weldments to improve mechanical properties of welded joints. The basic principle and device of rotating extrusion were introduced. The residual distortion and stresses in rotating extrusion weldments were compared with those in conventional weldments. The differences in microstructure and mechanical properties between conventional welded joints and rotating extrusion welded joints were investigated and analyzed in order to make clear the effect of rotating extrusion on the performance of aluminum alloy weldments. Experimental results show that rotating extrusion can enhance the hardness and tensile strength of aluminum alloy welded joints evidently. This method has also potential effect on extending the life of welded structures.

关键词： rotating extrusion aluminum alloy thin plate welding distortion mechanical property

Influence of laser energy input mode on joint interface characteristics in laser brazing with Cu-base filler metal

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中国有色金属学会会刊：英文版 2008年第5期18卷 1065-1070页

作者：李俐群封小松陈彦宾 state key laboratory of advanced welding production Technology Harbin Institute of Technology

The flange butt joints of 1 mm-thick galvanized steel sheets were brazed with CuSi3 as filler metal at different laser heating *** microstructures and element distributions of joint interface were investigated by SEM and *** results show that there is no obvious interface layer with the circular individual beam heating and lamellar Fe-Si intermetallic compound layer is found with dual-beam laser spot *** the irradiation of rectangular laser spot,the joint interface layer is also *** layer thickness is larger than that of dual-beam brazing and the layer shape is flat so that intermetallic compounds trend to grow into cellular ***,the interface layer shape also depends on its position in the *** the high heat input,dendritic or granular intermetallic compounds dispersively distribute in brazing seam adjacent to the interface,which is caused by the melting or dissolving of the base *** to the results,the brazing quality can be controlled by laser heating mode and processing parameters.

关键词：激光铜焊法接口特征激光能量输入模式焊接技术镀锌钢

Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with copper interlayer sheet

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Transactions of Nonferrous Metals Society of China 2010年第10期20卷 1829-1834页

作者：王廷张秉刚陈国庆冯吉才唐奇 state key laboratory of advanced welding production Technology Harbin Institute of Technology

Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with a copper sheet as interlayer was carried *** of the joint were studied by optical microscopy(OM),scanning electron microscopy(SEM) and X-ray diffractometry(XRD).In addition,the mechanical properties of the joint were evaluated by tensile test and the microhardness was *** two alloys were successfully welded by adding copper transition layer into the *** solution with a certain thickness was located at the interfaces between weld and base metal in both *** inside the weld and near the stainless steel were characterized by solid solution of copper with TiFe2 intermetallics dispersedly distributed in *** weld near titanium alloy contained Ti-Cu and Ti-Fe-Cu intermetallics layer,in which the hardness of weld came to the highest *** fracture occurred in the intermetallics layer when the joint was stretched.

关键词： Ti-15-3 titanium alloy 304 stainless steel electron beam welding interrnetallics layer mechanical properties

Joint performance of laser-TIG double-side welded 5A06 aluminum alloy

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中国有色金属学会会刊：英文版 2009年第1期19卷 26-31页

作者：陈彦宾苗玉刚李俐群吴林 state key laboratory of advanced welding production Technology Harbin Institute of Technology

The influence of welding parameters on mechanical properties and microstructure of the welds of laser-TIG double-side welded 5A06 aluminum alloy was investigated. The results show that the weld cross-sectional shape has an intimate relation with the mechanical properties and microstructure of the welds. The symmetrical "X" cross-section possesses a relatively higher tensile strength and elongation than the others, about 91% and 58% of those of base metal, respectively. The good weld profiles and free defects are responsible for the improvement of tensile properties. Due to low hardness of the fusion zone, this region is the weakest area in the tensile test and much easier to fracture. The loss of Mg element is responsible for the decrease of mechanical properties of the joints. The microstructure of "X" cross-section has an obvious difference along the direction of weld depth, and that of the "H" cross-section is consistent and coarse.

关键词：铝合金激光电弧双面焊接术特征分析

Si diffusion behavior during laser welding-brazing of Al alloy and Ti alloy with Al-12Si filler wire

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中国有色金属学会会刊：英文版 2010年第1期20卷 64-70页

作者：陈树海李俐群陈彦宾刘德健 state key laboratory of advanced welding production Technology Harbin Institute of Technology

In laser welding-brazing of Al alloy (5A06) and Ti alloy (Ti-6Al-4V) with rectangular CO2 laser spot and with Al-12Si filler wire, element Si enriches at the interface between Ti substrate and the filler metal. It is found that the Si diffusion behavior has a significant effect on the formation of interfacial intermetallic compounds. To analyze the Si diffusion behavior, a model for the prediction of the chemical potential for ternary alloy was established. According to the calculated results of the influence of the element content and temperature in Ti-Al-Si system on Si chemical potential, the diffusion behavior of Si element was analyzed for Ti dissolution and melting mode, which presents a good agreement with the experimental data. Further, formation mechanism of the interfacial intermetllic compound was clarified.

关键词：钛铝合金扩散行为激光焊接硅元素金属间化合物料线金属界面预测模型

Microstructural zones and tensile characteristics of friction stir welded joint of TC4 titanium alloy

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Transactions of Nonferrous Metals Society of China 2010年第10期20卷 1873-1878页

作者：刘会杰周利 state key laboratory of advanced welding production Technology Harbin Institute of Technology

TC4 titanium alloy was friction stir welded using a W-Re pin tool,and the defect-free weld was produced with proper welding *** joint consists of stir zone,heat affected zone and base *** stir zone is characterized by equiaxed dynamically recrystallized α phases and transformed β phases with fine α+β lamellar *** microstructure of the heat-affected zone is similar to that of the base material,but there is an increase in the volume fraction of β.Transverse tensile strength of the joint is 92% that of the base material,and the joint is fractured in the stir zone and the fracture surface possesses typical plastic fracture *** stir zone is the weakest part of the joint,through which the tensile characteristics of the TC4 joint can be explained.

关键词： friction stir welding titanium alloy microstructural zones tensile characteristics

Control of Titanium Alloy Thin Plate welding Distortion by Trailing Peening

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Journal of Materials Science & Technology 2003年第Z1期19卷 184-186页

作者： Xuesong LIU Hongyuan FANG Shude JI Zhibo DONG state key laboratory of advanced welding production Technology Harbin Institute of TechnologyHarbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001 China

The technology of trailing peening is a kind of promisingly bran-new technology which can be used to control weldingstress and distortion of Ti alloy thin plate. Control of TC4 Ti alloy thn plate welding stress and distortion underthe condition of conventional welding and trailing peening is performed, respectively. The results show that thetechnology of trailing peening effectively reduces deflection and transverse shrinkage of thin plate weldment. Themaximum deflection is decreased from 15 mm under the conditior of conventional welding to 5 mm, while the weldtransverse shrinkage is decreased from 0.5 mm to about 0.1 mm.

关键词： Control of residual stress and distortion, Trailing peening, TC4 Ti alloy

Simulation on Thermal Integrity of the Fin/Tube Brazed Joint of Heat Exchangers

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Journal of Materials Science & Technology 2003年第Z1期19卷 71-72页

作者： Yiyu QIAN Feng GAO Fengjiang WANG Hui ZHAO state key laboratory of advanced welding production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the thermal distribution at the brazed joint zone is related to not only the geometry of the fin and tube, butalso the brazed joint topology. A poor brazed joint will result in very poor heat transfer. Thermal contact resistanceis adopted to analyze the fin heat efficiency.

关键词： Thermal integrity, Fin efficiency, Thermal contact resistance, FEM

Simulation on Magnetostriction Strain of Polymer-bonded Terfenol-D Composites

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Journal of Materials Science & Technology 2003年第Z1期19卷 103-104页

作者： Jiuchun YAN Shixiong LU Shiqin YANG Shiyu HE state key laboratory of advanced welding production Technology Hanbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Hanbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Hanbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Hanbin Institute of Technology Harbin 150001 China

A model of magnetostrictive strain for polymer-bonded Terfenol-D composite is presented, which is composed of asubmodel for the average strain of Terfenol-D composite and a magnetostriction submodel for Terfenol-D *** results show that the saturation magnetostriction λs is very closely with experimental results, althoughthere exists some difference between the calculated and the experimental results under low applied magnetic *** saturation magnetostriction of the composites increases with the particle fraction (v1=72.5～90 vol. Pct) in thesimulated and experimental results, but the simulation result is not ideal when the particle fraction is higher than 85%.

关键词： Polymer-bonded Terfenol-D composite, Magnetostriction, Simulation