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Ultrasonic dissolution of brazing of 55% SiC_p/A356 composites

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Transactions of Nonferrous Metals Society of China 2010年第5期20卷 746-750页

作者：张洋闫久春陈晓光崔岩 state key laboratory of advanced welding Production Technology Harbin Institute of Technology

The brazing of 55% SiCp/A356 (volume fraction) composites in air using Zn-Al alloy as a filler metal was *** the brazing process,ultrasonic vibrations were applied to samples for bonding and a significant dissolution of the filler metal into the matrix alloy in the base materials *** brazing temperatures were increased,the thickness of the partial melting layers in the base material *** particles in the partial melting layer of the base material were transferred into the liquid filler under ultrasonic action and a bond with homogeneously distributed reinforcements was obtained after *** volume fraction of SiC particles in the bonds could be varied by changing the brazing *** maximum SiC particle volume fraction of the bond material reached 37% at a brazing temperature of 500 ℃.The shear strength of the brazed bonds was improved at pressures up to 244 MPa (at 20 ℃) and increased by 133.8% (at 200 ℃) compared with the filler of the Zn-based alloy.

关键词： aluminum matrix composites brazing ultrasonic dissolution of brazing composite bond

Mechanical properties of underwater friction stir welded 2219 aluminum alloy

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Transactions of Nonferrous Metals Society of China 2010年第8期20卷 1387-1391页

作者：刘会杰张会杰黄永宪于雷 state key laboratory of advanced welding Production Technology Harbin Institute of Technology

Underwater friction stir welding of 2219 aluminum alloy was carried out in order to further improve the joint performances by varying welding temperature *** results indicated that the tensile strength of the joint can be improved from 324 MPa by external water cooling action in normal to 341 ***,the plasticity of the joint is *** underwater joint tends to fracture at the interface between the weld nugget zone and the thermal mechanically affected zone on the advancing side during tensile test,which is significantly different from the normal joint.

关键词： aluminum alloy underwater friction stir welding mechanical property

Microstructures of surface modification layer on Q235 steel produced by laser melt injection of WC

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中国有色金属学会会刊：英文版 2009年第S3期19卷 558-562页

作者：李福泉陈彦宾李俐群 state key laboratory of advanced welding Production Technology Harbin Institute of Technology

WC powder was injected onto the surface of Q235 steel by laser melt injection (LMI). The influence of process parameters was studied. The microstructure and composition of the coatings were analyzed by SEM, XRD and EDS. The hardness and wear-resistant property of the coatings and Q235 steel were measured. The results show that LMI layer can be achieved only under the condition that process parameters meet the strict requirements. By optimizing the process parameter, excellent coatings can be acquired by injecting WC powder onto the surface of Q235 steel. The microstructure in the coatings is complex, which consists of WC, W2C and M6C(Fe3W3C-Fe4W2C) phases. The difference of Fe3W3C microstructure in different zones of the coatings is obvious. Both the compositions of the reaction layers around the particle and dendrite precipitation carbides in the upper coating are Fe3W3C. The average hardness of LMI layer is above HV 900, which is about four times that of Q235 steel. The friction coefficient of LMI layer is only one quarter that of the substrate, which indicates that the wear resistance of the coatings is enhanced sharply.

关键词： laser melt injection(LMI) WC surface modification layer wear-resistant property

Brazing of C/C composite and Ti-6Al-4V with graphene strengthened AgCuTi filler:Effects of graphene on wettability,microstructure and mechanical properties

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Chinese Journal of Aeronautics 2018年第7期31卷 1602-1608页

作者： Duo LIU Yanyu SONG Yinghao ZHOU Xiaoguo SONG Wei FU Jicai FENG state key laboratory of advanced welding and Joining Harbin Institute of Technology Shandong Provincial key laboratory of Special welding Technology Harbin Institute of Technology at Weihai

Graphene nanosheets（GNSs） strengthened AgCuTi composite filler（AgCuTiG） was used to braze C/C composite and Ti-6Al-4V. The effects of GNSs on the wettability of AgCuTiG filler on the C/C composite surface and the interfacial microstructure and mechanical properties of brazed joints were investigated. The results indicate that the addition of GNSs reduced the wettability of AgCuTiG. The interfacial microstructure of brazed joints evolved with the addition of GNSs, where Ti3Cu4 and TiCu4 were converted to TiCu and the thickness of the reaction layer adjacent to the base material decreased. The maximum shear strength of joints brazed at 0.3 wt% GNSs was 23.3 MPa（880℃/10 min）. Further adding GNSs deteriorated the shear strength of the joints. Fracture of the joints occurred in the C/C composite substrate and the TiC layer adjacent to C/C composite.

关键词： Brazing Graphene nanosheets Mechanical properties Microstructure Wetting

Repair welding process of friction stir welding groove defect

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中国有色金属学会会刊：英文版 2009年第3期19卷 563-567页

作者：刘会杰张会杰 state key laboratory of advanced welding Production Technology Harbin Institute of Technology

The groove defect formed in the friction stir welding dramatically deteriorates weld appearances and mechanical properties of the joints owing to its larger size and penetration. Therefore, the friction stir repair welding was utilized to remove such a groove defect, and the focus was placed on the mechanical properties and microstructural characteristics of the repair joints so as to obtain an optimum repair welding process. The experimental results indicate that the groove defect can be removed by friction stir repair welding, and the offset repair welding process is superior to the symmetrical repair welding process. In the symmetrical repair welding process, a large number of fine cavity defects and an obvious aggregation of hard-brittle phase Al2Cu occur, accordingly the mechanical properties of the repair joint are weakened, and the fracture feature of repair joint is partially brittle and partially plastic. A good-quality repair joint can be obtained by the offset repair welding process, and the repair joint is fractured near the interface between the weld nugget zone and thermal-mechanically affected zone.

关键词：搅拌摩擦焊接缺陷形成补焊工艺焊接修复力学性能修复过程显微组织关节

Vacuum brazing of GH99 superalloy using graphene reinforced BNi-2 composite filler

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Journal of Materials Science & Technology 2018年第10期34卷 1843-1850页

作者： Duo Liu Yanyu Song Bin Shi Qi Zhang Xiaoguo Song Hongwei Niu Jicai Feng state key laboratory of advanced welding and Joining Harbin Institute of Technology Shandong Provincial key laboratory of Special welding Technology Harbin Institute of Technology at Weihai

A novel graphene reinforced BNi-2 composite filler was developed for brazing GH99 superalloy. The interracial microstructure of brazed joints was analyzed by field emission scanning electron microscope and a transmission electron microscope. The effects of graphene addition on the microstructure evolu-tion and mechanical properties of brazed joints were investigated, and the strengthening mechanism of graphene was analyzed. The results revealed that due to the addition of graphene, M23（C,B）6 compounds were synthesized in the y solid solution and brittle boride precipitates near the brazing seam decreased. Graphene was effective in retarding solute atoms diffusion thus impeding the precipitation of borides. Furthermore, the low coefficient of thermal expansion （CTE） of graphene was conducive to relieve stress concentration of the brazed joints during the cooling process. The shear strengths of brazed joints were significantly improved by exerting the strengthening effect of graphene. The maximum shear strengths of the brazed joints were 410.4 MPa and 329.7 MPa at room temperature and 800 ℃, respectively.

关键词： Graphene GH99 superalloy Brazing Microstructure Mechanical properties

Liquid-Phase-Impacting Diffusion welding Mechanism and Microstructure of Welded Joint of Al Matrix Composite SiCp/101A

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Journal of Materials Science & Technology 2003年第Z1期19卷 179-181页

作者： Jitai NIU Wei GUO Qingchang MENG Xinmei ZHANG Xingqiu LIU Guangtao ZHOU The state key laboratory of advanced welding Production Technology Harbin Institute of Technology Harbin 150001 China The state Kdy laboratory of Metal Matrix Composite Shangai Jiao Tong University Shanghai 200030China The State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China The State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China The State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China The State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China The State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

The liquid-phase-impacting (LPI) diffusion welding mechanism and microstructure of welded joint of aluminum matrixcomposite SiCp/101A have been studied. It shows that by LPl diffusion welding, the interface state between SiCparticle and matrix is prominent, the harmful microstructure or brittle phase can be restrained from the welded ***, the density of dislocation in the matrix near the interface and in the matrix are all so higher than that ofparent composite, the dislocation entwists each other intensively resulted in welding the composite successfully.

关键词： Aluminum matrix composite, Liquid-phase-impacting diffusion welding, SiCp/101A

Effect of 2–6 at.% Mo addition on microstructural evolution of Ti-44Al alloy

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Journal of Materials Science & Technology 2018年第7期34卷 1196-1204页

作者： S.Z.Zhang Z.W.Song J.C.Han C.J.Zhang P.Lin D.D.Zhu F.T.Kong Y.Y.Chen School of Materials Science and Engineering Taiyuan University of Technology Shanxi key laboratory of advanced Magnesium-Based Materials Taiyuan University of Technology School of Mechanical Engineering Taiyuan University of Technology School of Mechanical Engineering Quzhou University state key laboratory for advanced welding and jointing Harbin Institute of Technology

In order to understand the effect of Mo alloying on the microstructural evolution of TiAl alloy, the as-cast microstructure, heat treated microstructure characteristic, and hot compression microstructure evolution of Ti-44Al alloy have been studied in this work. The as-cast microstructure morphology changes from （γ＋α2） lamellar colony and β/β0＋γ mixture structure to β/β0 phase matrix widmannstatten structure, when Mo content increases from 2 at.% to 6 at.%. Affected by the relationship between β phase and α90℃phase, the angles between the lamellar orientation and the block β/β0 phase are roughly at 0℃, 45℃ and 90℃. Comparing with heat treatment microstructure, the hot compression microstructure contains less β/β0 phase, however, theβ/β0 phase containing 2Mo alloy and 3Mo alloy hot compressed at 1275 ℃ has the inverse tendency. In addition, （α2 ＋γ） colony is decomposed by the discontinuous transformation.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Phase transformation Titanium aluminides Heat treatment Microstructure evolution,β/βo phase

Microstructure,Corrosion and Mechanical Properties of Medium-Thick 6061-T6 Alloy/T2 Pure Cu Dissimilar Joints Produced by Double Side Friction Stir Z Shape Lap-Butt welding

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 385-400页

作者： Jiuxing Tang Guoxin Dai Lei Shi Chuansong Wu Sergey Mironov Surendra Kumar Patel Song Gao Mingxiao Wu MOE key Lab for Liquid-Solid Structure Evolution and Materials Processing Shandong UniversityJinan 250061China laboratory of Mechanical Properties of Nanoscale Materials and Superalloys Belgorod State UniversityBelgorod 308015Russia School of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China state Grid Henan Electric Power Research Institute Zhengzhou 450052China

A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar *** influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically *** indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding ***-FSZW joint was prone to form void defects in the bottom of the second-pass *** recrystallization mechanisms at the top and middle of the weld nugget zone(WNZ)were continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX).While the major recrystallization mechanism at the bottom of the WNZ was ***-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface,and the maximum tensile strength of this joint is 160.57 MPa,which is equivalent to 65.54%of pure Cu base ***,the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/*** demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance.

关键词： DS-FSZW Al/Cu dissimilar joint Corrosion behaviour Intermetallic compounds Microstructure Mechanical properties