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3D modeling for effect of tool eccentricity on coupled thermal and material flow characteristics during friction stir welding

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Transactions of Nonferrous Metals Society of China 2024年第10期34卷 3309-3325页

作者： Hao SU Ji CHEN Chuan-song WU Key Laboratory for Liquid−Solid Structural Evolution&Processing of Materials Ministry of EducationInstitute for Materials JoiningShandong UniversityJinan 250061China

A novel three-dimensional numerical model is proposed to investigate the effect of tool eccentricity on the coupled thermal and material flow characteristics in friction stir welding(FSW) *** asymmetrical boundary condition at the tool-workpiece interface,and the dynamic mesh technique are both employed for the consideration of the tool eccentricity during tool *** is found that tool eccentricity induces the periodical variation of the heat densities both at the tool-workpiece interface and inside the shear layer,but the fluctuation amplitudes of the heat density variations are ***,it is demonstrated that tool eccentricity results in significant variation of the material flow behavior in one tool rotating ***,the material velocity variation at the retreating side is particularly important for the formation of the periodic characteristics in *** modeling result is found to be in good agreement with the experimental one.

关键词： friction stir welding tool eccentricity thermal behavior periodic material flow numerical simulation

friction stir welding of AZ31 magnesium alloys processed by equal channel angular pressing

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Rare Metals 2008年第4期27卷 393-399页

作者： ZHANG Bing YUAN Shouqian WANG Xunhong Department of Metallurgy Engineering Xi ＇an University of Architecture and Technology Xi＇an 710055 China

Equal channel angular pressing （ECAP） is an effective thermo-mechanical process to make ultrafine grains. An investigation was carried out on the friction stir welding （FSW） of ECAPed AZ31 magnesium alloys with a thickness of 15 mm. For different process parameters, the optimum FSW conditions of ECAPed AZ31 magnesium alloys were examined. The basic characterization of weld formation and the mechanical properties of the joints were discussed. The results show that the effect of welding parameters on welding quality was evident and welding quality was sensitive to welding speed. Sound joints could be obtained when the welding speed was 37.5 mm/min and the rotation speed of the stir tool was 750 r/min. The maximum tensile strength （270 MPa） of FSW was 91% that of the base materials. The value of microhardness varied between advancing side and retreating side because of the speed field near the pin of the stir tool, which weakened the deformed stress field. The value of microhardness of the welding zone was lower than that of the base materials. The maximum value was located near the heat-affected zone （HAZ）. Remarkable ductile character was observed from the fracture morphologies of welded joints.

关键词： equal channel angular pressing friction stir welding magnesium alloys grain refinement mechanical properties

friction stir welding of Al Alloy Thin Plate by Rotational Tool without Pin

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Journal of Materials Science & Technology 2011年第7期27卷 647-652页

作者： Liguo Zhang Shude Ji Guohong Luan Chunlin Dong Li Fu School of Aerospace Engineering Shenyang Aerospace University Shenyang 110136 China China FSW Center Beijing 100024 China Shenyang Aircraft Design & Research Institute Shenyang 110035 China State Key Laboratory for Manufacturing Systems Engineering Xi an Jiaotong University Xi an 710049 China

For friction stir welding （FSW）, a new idea is put forward in this paper to weld the thin plate of Al alloy by using the rotational tool without pin. The experiments of FSW are carried out by using the tools with inner-concave-flute shoulder, concentric-circles-flute shoulder and three-spiral-flute shoulder, respectively. The experimental results show that the grain size in weld nugget zone attained by the tool with three-spiral-flute shoulder is nearly the same while the grain sizes decrease with the decrease of welding velocity. The displacement of material flow in the heat-mechanical affected zone by the tool with three-spiral-flute shoulder is much larger than that by the tool with inner-concave-flute shoulder or concentric-circles–flute shoulder. The above-mentioned results are verified by numerical simulation. For the tool with three-spiral-flute shoulder, the tensile strength of FSW joint increases with the decrease of welding velocity while the value of tensile strength attained by the welding velocity of 20 mm/min and the rotation speed of 1800 r/min is about 398 MPa, which is 80% more than that of parent mental tensile strength. Those verify that the tool with three-spiral-flute shoulder can be used to join the thin plate of Al alloy.

关键词： friction stir welding Rotational tool without pin Shoulder shape Plastic flow

friction stir welding of carbon nanotubes reinforced Al-Cu-Mg alloy composite plates

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Journal of Materials Science & Technology 2017年第9期33卷 1004-1008页

作者： Ke Zhao Zhenyu Liu Bolyu Xiao Zongyi Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

Carbon nanotubes(CNTs) reinforced Al-Cu-Mg composite plates of 2.2 mm in thickness after extrusion and T4 treatment were joined by friction stir welding(FSW) and the joint efficiency reaches 87%. There was no precipitate in both heat-affected zone(HAZ) and nugget zone(NZ) as a medium rotation rate of 800 rpm and a relative high travel speed of 100 mm min-1were used. In the NZ, FSW disarranged the alignment of CNTs to random orientation and dispersed CNT uniformly. The orientation of CNTs perpendicular to the tensile direction and the possible dissolution of solute clusters made the HAZ become the weakest zone in the joint leading to the failure in the HAZ.

关键词： Carbon nanotubes Metal matrix composites friction stir welding

friction stir welding of Discontinuously Reinforced Aluminum Matrix Composites:A Review

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Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 816-824页

作者： D.Wang B.L.Xiao D.R.Ni Z.Y.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

friction stir welding （FSW） is considered a promising welding technique for joining the aluminum matrix composites （AMCs） to avoid the drawbacks of the fusion welding. High joint efficiencies of 60%-100% could be obtained in the FSW joints of AMCs. However, due to the existence of hard reinforcing particles in the AMCs, the wearing of welding tool during FSW is an unavoidable problem. Moreover, the low ductility of the AMCs limits the welding process window. As the hard materials such as Ferro-Titanit alloy, cermet, and WC/Co were applied to produce the welding tools, the wearing of the tools was significantly reduced and the sound joints could be achieved at high welding speed for the AMCs with low reinforcement volume fraction. In this article, current state of understanding and development of welding tool wearing and FSW parameters of AMCs are viewed. Furthermore, the factors affecting the microstructure and mechanical properties of the joints are evaluated in detail.

关键词： Metal matrix composite friction stir welding Particle, microstructure Wear

friction stir welding of Zr_(55)Al_(10)Ni_5Cu_(30) Bulk Metallic Glass to Crystalline Aluminum

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Journal of Materials Science & Technology 2009年第6期25卷 853-856页

作者： Zuoxiang Qin Cuihong Li Haifeng Zhang Zhongguang Wang Zhuangqi Hu Zhiqiang Liu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academic of Sciences Shenyang 110016 China School of Materials Science and Engineering Dalian Jiaotong University Dalian 116028 China

The Zr55Al10Ni5Cu30 bulk metallic glass plate were successfully welded to crystalline aluminum plates by using a friction stir welding （FSW） method. The welded zone was examined. No defects, cracks or pores were observed and no other crystalline phases except for aluminum were found in the welded joint. The strength of the joint is higher than that of aluminum. The glassy phase in the stir zone keeps the amorphous state, showing a successful welding. The storage modulus softens over the glass transition. And the weldability was discussed according to this phenomena.

关键词： Bulk metallic glass Zr-based alloy friction stir welding

friction stir welding of Aluminum Alloys

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Journal of Wuhan University of Technology(Materials Science) 2004年第1期19卷 61-64页

作者：傅志红 Zhuzhou Institute of Technology

friction stir welding(FSW),a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys *** processing of FSW,the microstructure in FSW alloys and the factors inf... 详细信息

关键词： friction stir welding stir-welding head aluminum alloy microstructure

friction stir welding of copper alloys

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China welding 2007年第4期16卷 64-67页

作者：刘书华刘孟王德庆徐振越 Institute of Materials Science and Engineering Dalian Jiaotong University Technology Center of Angang Steel Co. Ltd.

Copper plates ,brass plates and copper/brass plates were friction stir welded with various parameters. Experimental results show that the microstructure of the weld is characterized by its much finer grains as contrasted with the coarse grains of parent materials and the heat-affected zones are very narrow. The microhardness of the copper weld is a little higher than that of parent plate. The microhardness of brass weld is about 25% higher than that of parent material. The tensile strength of copper joints increases with increasing welding speed in the test range. The range of parameters to obtain good welds for copper is much wider than that for brass. When different materials were welded, the position of copper plate before welding affected the quality of FSW joints. If the copperplate was put on the advancing side of weld, the good quality of weld could be got under proper parameters.

关键词： friction stir welding copper brass grain

friction stir welding Effect on Transverse Rigidity and Sound Transmission Characteristics of AZ31B Magnesium Alloy

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Transactions of Tianjin University 2015年第1期21卷 64-68页

作者：罗智郝志勇倪丁瑞郑旭 Department of Energy Engineering Zhejiang University Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

AZ31B magnesium alloy was subjected to friction stir welding with various welding parameters. The equivalent Young's moduli of the friction stir welded samples and the base material were obtained by the three-point method, and their transverse rigidities were obtained as well. Furthermore, the sound transmission characteristics of those samples were experimentally studied by four-microphone impedance tube method. The experimental results indicate that the transverse rigidities of the friction stir welded samples were only 79%, 83% and 92% of those of the base material, respectively. The sound transmission losses of the processed samples were also lower, which was largely due to the reduction of transverse rigidities induced by the decrease of equivalent Young's moduli.

关键词： AZ31B magnesium alloy friction stir welding transverse rigidity sound transmission loss