Orbital friction stir lap welding in tubular parts of aluminium alloy AA5083

In this study, orbital friction stir lap welding of 360?mm diameter AA5083-H321 tube to 350?mm diameter AA5083-O flange was investigated. The influence of rotational and travel speed of tool with triangular frustum pin on the metallurgical structure and mechanical properties of orbital friction stir lap welded samples were studied. The results indicated that defect free orbital lap joints are successfully obtained using tool rotational speed of 650 and 800?rev?min^?1 with a constant travel speed of 40?mm?min^?1. The strengthening mechanism in the stir zone is solid solution strengthening and dislocation looping. The maximum joint strength was achieved at a welding speed of 650?rev?min^?1 and 40?mm?min^?1. Failure of tensile shear test samples occurred far from the friction stir welding zone.     

搅拌摩擦加工修复AA5083/T2紫铜爆炸复合板界面

基于多道次搅拌摩擦加工(M-FSP)修复AA5083/T2紫铜爆炸复合板的界面缺陷,探讨界面形貌和界面结合机制.结果表明,搅拌摩擦加工过程中的高旋转速度和低前进速度会产生更多的热量.当旋转速度设定在1200 r/min,前进速度设定在30 mm/min,搭边量设定在2/24时,AA5083/T2紫铜复合板经多道次搅拌摩...     

Pitting and stress corrosion cracking resistance of friction stir welded AA 5083

The corrosion behaviour of friction stir welded (FSW) joints of AA 5083 has been compared to that of MIG welded joints. Pitting and stress corrosion cracking (SCC) resistance in 3.5% NaCl + 0.3 g/l H₂O₂ and in EXCO (4 M KCl + 0.5 M KNO₃ + 0.1 M HNO₃) solutions has been determined at 25°C. SCC susceptibility was evaluated by slow strain rate tests (SSRT), at a strain rate of 1 × 10⁻⁶ s⁻¹.Welds obtained by FSW technique showed a higher corrosion resistance in EXCO solution and a lower pitting tendency than the base alloy. Electrochemical measurements (corrosion potential measurements, polarization curves recording) evidenced that FSW weld was cathodic to base alloy. FSW joints were not susceptible to SCC in both test solutions, whereas MIG joints cracked in both solutions.     

Joint characteristics and dissimilar materials joining of pure-Al/5083 by friction stir welding

Friction stir welding (FSW)^1,2, developed in 1991 by The Welding Institute, UK is a joining process which overthrew welding concepts which existed at the time; its application has been progressed not only for soft alloys including aluminium, but also, in recent years, for steel.³ Sato and others carried out friction stir welding on 1080-O and 5083-O materials and investigated variations in the hardness.⁴ Ten years or so have passed since the development of friction stir welding, the process has been globally investigated and widely employed in various sectors such as vehicles, ships and the aerospace industry. Furthermore, investigations have also been carried out into the manufacture of dissimilar metal joints. For example, Enomoto studied 2024/AC4C cast alloy and reportedly obtained satisfactory joints.⁵ Li and others have investigated 2024/6061 and reported that both alloys are distributed at the weld zone in a stratified and complex manner.⁶     

Variations in stir zone and thermomechanically affected zone of dissimilar friction stir weld of AA5083 and AA6082 alloys

Variations in composition, microhardness (in the thermomechanically affected zone) and texture in the tool domain of the dissimilar friction stir weld of AA5083-O and AA6082-T6 alloys were investigated. The contents of the major alloying elements in the weld zones were determined using inductively coupled plasma?atomic emission spectroscopy. It was observed that a slight drop in the content of the alloying elements results from the friction stir welding process with the Mg content being the most affected amongst the major alloying elements in the two alloys. By relating the mass fractions of the major alloying elements in the parent metals of both alloys to those of the stir zone, the relative proportions of the two alloys in the stir zone were estimated with the results showing that at least 60% of the materials in the stir zone are from the retreating side of the weld. It was also revealed that the changes in the hardness profile in the thermomechanically affected zone of the retreating side are predominantly influenced by changes in grain size in that domain. Finally, the investigation further revealed that the texture component in the tool shoulder domain is different from the texture component in the tool pin domain.     

AA2219铝合金搅拌摩擦焊接工艺窗口的建立

建立AA2219铝合金搅拌摩擦焊接的工艺窗口。采用不同的工艺参数如旋转速度和焊接速度来焊接该铝合金。通过对焊接接头的宏观形貌分析,建立搅拌摩擦焊的工艺窗口。通过拉伸试验、显微组织观察,对工艺窗口不同区域的接头强度进行分析。焊接接头断裂的位置与最低硬度分布相关。所建立的工艺窗口可以用来选择适当的工艺参数来获得高质量的AA2219铝合金搅拌摩擦焊接。     

搅拌摩擦焊接工艺参数对AA6061-B4C焊接接头抗拉强度的影响（英文）

搅拌摩擦焊(FSW)是一种固态连接技术,可用来连接高强度铝合金及多种陶瓷颗粒增强金属基复合材料(MMCs)。搅拌摩擦焊获得的陶瓷增强金属基复合材料焊缝优良,在增强体与基体间没有发生有害反应。对搅拌摩擦焊接工艺参数对AA6061-B4C焊接接头抗拉强度的影响进行研究。采用4因素5水平的中心复合设计来控制实验的次数。构建一数学模型来分析搅拌摩擦焊工艺参数对接头抗拉强度的影响。结果表明,在旋转速度1000r/min、焊接速度1.3mm/s、轴向力10kN、增强相含量12%的条件下,搅拌摩擦焊得到的焊接接头的抗拉强度最大。根据构建的模型采用广义简约梯度算法进行优化以得到最大的抗拉强度。金相分析表明,在焊接接头中出现了多种区域,如焊合区、热力影响区和热影响区。在焊合区观察到大量的被细化的铝基体晶粒以及粒径明显减小的B4C颗粒。在热力影响区出现塑性变形、热影响和被拉长的铝晶粒。     

Microstructure,mechanical properties and residual stresses as a function of welding speed in aluminium AA5083 friction stir welds

Friction stir welding (FSW), like other friction welding techniques, has the advantage that many of the welding parameters, e.g. tool design, rotation speed and translation speed, can be controlled in a precise manner, thus controlling the energy input into the system. However, the effect of different welding speeds on the weld properties remains an area of uncertainty. In this paper, we report the results of microstructural, mechanical property and residual stress investigations of four aluminium AA5083 friction stir welds produced under varying conditions. It was found that the weld properties were dominated by the thermal input rather than the mechanical deformation by the tool.     

Force generation during friction stir welding of AA2024-T3

Force measurement in friction stir welding (FSW) provides a significant insight into the process in terms of machine and tool limitations and design. In the present research the tool forces were investigated experimentally using a rotating component dynamometer and through the development of a finite element model. The model correlated well with experimental temperatures and tool forces and was capable of predicting tool forces for different welding parameters, predicting regions were tool failure is likely to occur and identifying tool pin designs which can process the workpiece more efficiently.     

5083铝合金搅拌摩擦焊接头的微观组织与力学性能

通过金相分析、拉伸及断口形貌观察等方法研究8 mm厚5083铝合金搅拌摩擦焊接头的显微组织和力学性能.金相观察结果表明:焊核区由细小的等轴晶组织构成;热机影响区受机械和热的双重作用组织发生了较大程度的变形;热影响区仅受热循环的作用,与母材组织相似,但组织稍微有粗化现象.力学试验表明:焊接速度为160 mm/min时,接...     

Experimental verification of heat input during friction stir welding of Al alloy 5083

Heat input during welding is a basic index for weld quality and service properties associated with the resulting microstructure. In this study, the heat inputs during friction stir welding of Al alloy 5083 at various welding parameters were measured by calorimetry. Multiple regression analysis of the data was conducted to determine an empirical equation to estimate the heat input with the input variables. The effect of the heat input on the grain size of the stir zone was also examined, and a good correlation between the grain size and heat input was obtained. This study obtained a systematic relationship between the input variables, heat input and grain size of the stir zone through experimental measurements.     

5083铝合金搅拌摩擦焊与MIG焊缝腐蚀性能对比

对5083铝合金FSW（搅拌摩擦焊）和MIG（熔化极氩弧焊）焊缝的微观显微组织和腐蚀性能进行了分析.结果表明,FSW焊缝由细小的等轴再结晶组织构成,而MIG焊缝晶粒粗大,组织不均匀.电化学腐蚀试验表明,主轴旋转频率为300 r/min,焊接速度为160 mm/min,搅拌头倾角为3°的FSW焊缝与MIG焊缝相比,腐蚀电...     

5083铝合金搅拌摩擦焊接头微弧氧化表面防护

采用微弧氧化技术在5083铝合金搅拌摩擦焊接头表面制备一层均匀的陶瓷膜。通过扫描电镜（SEM）、X射线衍射（XRD）和显微硬度测试分析了微弧氧化膜的形貌、相组成和显微硬度,并采用浸泡方法研究了微弧氧化膜对焊接接头耐腐蚀性能的影响。结果表明,接头表面微弧氧化膜均匀致密,铝合金焊缝区的显微硬度低于母相区,但微弧氧化膜的硬度比铝合金基体提高一个数量级,并且不同区域对应的微弧氧化膜硬度相同。在0.2 mol/L NaHSO3＋0.6 mol/L NaCl溶液中浸泡3天后,未氧化处理的焊接样品表面出现孔蚀,而微弧氧化处理的样品表面没有观察到腐蚀迹象。     

Microstructure and mechanical properties of friction stir welded aluminium alloys with special reference to AA 5083 and AA 6082

Abstract

Aluminium alloys AA 5083 and AA 6082 have been friction stir welded and the mechanical properties and microstructures of the welds have been evaluated. Alloy AA 5083 mainly fractured near the centre of the weld, while fracture in AA 6082 mainly occurred in the heat affected zone. The tensile strength of welded joints in AA 6082 was lower than the base material strength, but still met classification societies' requirements. Hardness was approximately constant across the welded zone in AA 5083, while a minimum in hardness was found in the AA 6082 welds. The location of the fracture closely matched the minimum hardness region. Very fine scale precipitation in AA 6082 was significantly affected by the weld thermal cycle. In the zone of lowest hardness, the hardening precipitate (β″-Mg₅Si₆) had transformed to the non-hardening β′-Mg_1.7Si. This is probably the main reason for the minimum in hardness, the fracture location, and the decreased tensile strength. Results are compared to a similar investigation of aluminium alloy AA 7075.     

闭孔CNTs/Al复合泡沫搅拌摩擦焊工艺研究

闭孔Al复合泡沫作为一种典型轻质高强材料,在汽车及航空航天领域具有明确需求牵引和应用前景。采用传统方法制备泡沫铝时,生产工艺复杂、样品尺寸受限,严重阻碍了大规模生产。本文提出基于搅拌摩擦焊制备闭孔CNTs/Al复合泡沫新工艺,解决制备大面积闭孔复合泡沫的难题。利用扫描电镜对不同焊接旋转速度的闭孔CNTs/Al复合泡沫预制体及复合泡沫的微观组织进行分析;采用红外线测温仪对焊接过程中预制体温度分布进行研究。利用电子万能试验机对纯Al泡沫和不同孔隙率闭孔泡沫的屈服应力和平台应力进行对比。研究结果表明：当搅拌头旋转速度为1000rpm时,闭孔CNTs/Al复合泡沫预制体表面平滑而致密。同时,增强体CNTs均匀分布在复合泡沫预制体横截面上。在发泡温度650℃,680℃和700℃对比可知,最佳发泡温度为680℃发泡15min,泡孔结构均匀,孔隙趋于圆形,最大泡孔直径为0.48mm。常温压缩时,闭孔复合泡沫的应力-应变曲线表现出脆性与韧性相结合的变形特征。孔隙率为30.5%时,闭孔泡沫的屈服应力和平台应力值最大。同时,与纯Al泡沫相比,闭孔泡沫的屈服应力提高了2-2.8倍;平台应力提高了1.4-2.9倍。     

AA5083铝合金的搅拌摩擦焊接工艺参数对搅拌头受力和热输入的影响(英文)

采用系统实验设计方法研究AA5083铝合金搅拌摩擦焊接工艺参数对搅拌头受力和热量输入的影响,得到了用来设计搅拌摩擦焊搅拌头和焊机的经验模型。当采用计算机来控制搅拌摩擦焊接时,这些模型可用来确定AA5083这类铝合金的摩擦焊接工艺参数、编制焊接程序及工艺参数控制。结果表明:影响轴向力和热量输入的重要参数是搅拌头转速、焊接速度和搅拌头轴肩直径,而影响纵向应力的重要参数是焊接速度和探头直径。     

异种搅拌摩擦焊AA5083-H111和AA6351-T6铝合金的力学和冶金性能(英文)

研究异种搅拌摩擦焊AA5083-H111和AA6351-T6铝合金的微观结构和力学性能。在3种不同的焊接速度(36、63、90 mm/min)下焊接AA5083-H111和AA6351-T6铝合金,分析焊接速度对接头力学和冶金性能的影响。结构表明,与其他焊接速度相比,焊接速度为63 mm/min时接头的力学性能和冶金性能较好。焊缝区由未混合区、机械混合区和混流区组成。所观察到的断裂模式为韧性纤维断裂。     

Knowledge discovery for friction stir welding via data driven approaches

Abstract

For a comprehensive understanding towards friction stir welding (FSW) which would lead to a unified approach that embodies materials other than aluminium, such as titanium and steel, it is crucial to identify the intricate correlations between the controllable process conditions, the observable internal process variables, and the characterisations of the post-weld materials. In Part 1 of this paper, multiple correlation analyses techniques have been developed to detect new and previously unknown correlations between the internal process variables and weld quality of aluminium alloy AA 5083. Furthermore, a new exploitable weld quality indicator has, for the first time, been successfully extracted, which can provide an accurate and reliable indication of the as welded defects. All results relating to this work have been validated using real data obtained from a series of welding trials that utilised a new revolutionary sensory platform called ARTEMIS developed by TWI Ltd, the original inventors of the FSW process.     

Effects of thread interruptions on tool pins in friction stir welding of AA6061

In this work, effects of pin thread and thread interruptions (flats) on weld quality and process response parameters during friction stir welding (FSW) of 6061 aluminium alloy were quantified. Otherwise, identical smooth and threaded pins with zero to four flats were adopted for FSW. Weldability and process response variables were examined. Results showed that threads with flats significantly improved weld quality and reduced in-plane forces. A three-flat threaded pin led to production of defect-free welds under all examined welding conditions. Spectral analyses of in-plane forces and weld cross-sectional analysis were performed to establish correlation among pin flats, force dynamics and defect formation. The lowest in-plane force spectra amplitudes were consistently observed for defect-free welds.