5A06/T2异种材料搅拌摩擦焊接头的耐蚀性

为了研究Al/Cu异种材料搅拌摩擦焊焊缝的耐腐蚀性能,对4mm的5A06和T2搅拌摩擦焊焊接接头进行了浸泡腐蚀试验。结果表明,焊缝区的耐腐蚀性能比铝合金母材要差,而焊缝铝铜结合过渡区耐腐蚀性能最差,并在该区域产生了腐蚀沟。电子能谱和X射线衍射物相分析结果发现,在过渡区Mg含量比其它区域高,而且有少量Al4Cu9产生,它的自腐蚀电位比铝高,这是导致该区域严重腐蚀的主要原因。     

铝/铜异种材料搅拌摩擦焊接工艺的优化

搅拌摩擦焊(FSW)是近几年发展较快的新型摩擦焊接技术.国内外研究较多的是铝合金及异种铝合金的搅拌摩擦焊接,但对铝/铜异种搅拌摩擦焊接的研究尚不多见.在此通过大量试验,分别在900-1500 rpm、20-50mm/min范围内调整搅拌旋转速度和焊接速度,优化焊缝的成形质量.结果表明,优化工艺参数可以实现铝/铜异种金属...     

Microstructure and Mechanical Properties of Dissimilar Double-Side Friction Stir Welds Between Medium-Thick 6061-T6 Aluminum and Pure Copper Plates

It is difficult to achieve Al/Cu dissimilar welds with good mechanical properties for medium-thick plates due to the inherent high heat generation rate at the shoulder-workpiece contact interface in conventional friction stir welding. Thus, double-side friction stir welding is innovatively applied to join 12-mm medium-thick 6061-T6 aluminum alloy and pure copper dissimilar plates, and the effect of welding speeds on the joint microstructure and mechanical properties of Al/Cu welds is systematically analyzed. It reveals that a sound Al/Cu joint without macroscopic defects can be achieved when the welding speed is lower than 180 mm/min, while a nonuniform relatively thick intermetallic compound (IMC) layer is formed at the Al/Cu interface, resulting in lots of local microcracks within the first-pass weld under the plunging force of the tool during friction stir welding of the second-pass, and seriously deteriorates the mechanical properties of the joint. With the increase of welding speed to more than 300 mm/min void defects appear in the joint, but the joint properties are still better than the welds performed at low welding speed conditions since a continuous uniform thin IMCs layer is formed at the Al/Cu interface. The maximum tensile strength and elongation of Al/Cu weld are, respectively, 135.11 MPa and 6.06%, which is achieved at the welding speed of 400 mm/min. In addition, due to the influence of welding distortion of the first-pass weld, the second-pass weld is more prone to form void defects than the first-pass weld when the same plunge depth is applied on both sides. The double-side friction stir welding is proved to be a good method for dissimilar welding of medium-thick Al/Cu plates.     

转速对6061铝合金/纯铜异种金属搅拌摩擦焊接头组织与性能的影响

采用搅拌摩擦焊技术对4 mm厚6061-T6铝合金和纯铜进行连接,研究转速对铝铜异种金属接头组织与力学性能的影响。结果表明,当焊接速度为30 mm/min、搅拌头转速在1 200~1 800 r/min的范围内,可以获得表面成形良好、无缺陷的铝铜异种金属接头。大量破碎的铜被搅入焊核区,形成了组织结构复杂的区域。通过EDS和XRD分析,在焊核区内发现了Al_2Cu、Al_4Cu_9和Al Cu金属间化合物。在界面处,铝和铜发生相互扩散形成金属间化合物层,随着转速的提高,化合物层逐渐变厚。由于晶粒细化、固溶强化作用以及金属间化合物的生成,异种接头的焊核区平均显微硬度值高于铝铜两侧平均硬度,并且在焊核区出现硬度峰值点。随着转速的增加,接头抗拉强度呈现先增大后减小的趋势,所得最优接头抗拉强度为183 MPa,达到铜母材的71.8%,断裂位置位于铝侧热影响区,断裂方式为韧性断裂。     

Microstructural characterization and mechanical properties of aluminum 6061-T6 plates welded with copper insert plate (Al/Cu/Al) using friction stir welding

Friction stir welding was used to join two aluminum 6061-T6 plates with an insert of a pure copper plate (Al/Cu/Al), and then the influence of the copper insert on the joint performance was studied. The dissimilar welding results were also compared with AA 6061 friction stir welds produced without copper insert (Al/Al). Optical and scanning electron microscopes were used for the microstructural observations of the welded samples. X-ray diffraction analysis was used to analyze phase component of the Al/Cu/Al specimen. A defect-free joint was observed for the Al/Cu/Al joint at a rotational speed of 950 r/min and a welding speed of 50 mm/min. Microstructural observation of the weld nugget zone (WNZ) demonstrates the formation of composite-like structure which promotes metallurgical bonding of aluminum and copper. XRD results show the formation of intermetallic compounds (IMCs), such as Al₄Cu₉ and Al₂Cu. Furthermore, it was observed that the hardness of the weld with the Cu insert plate is higher than that of other samples due to more dislocation density and a distinct rise in hardness values was observed due to the presence of IMCs. The ultimate tensile strength of the joint with copper insert plate is higher than that of the other sample due to the strong metallurgical bonding between Al and Cu.     

母材相对位置对搅拌摩擦焊接铝/铜异种金属接头性能的影响

铝、铜两种金属性能差异较大,用常规焊接方法难以实现连接,极大地限制了铝/铜复合接头的质量和应用范围.利用搅拌摩擦焊接技术成功焊接了防锈铝合金/紫铜异种金属的对接接头,通过焊缝接头表面宏观形貌观察、接头横断面组织分析及接头的抗拉强度分析母材相对位置对铝/铜搅拌摩擦焊接头性能的影响.结果表明,搅拌针相对配合面存在偏移的情况...     

Ti/Al异种合金搅拌摩擦焊搭接接头的界面特性(英文)

采用搅拌摩擦焊实现TC1钛合金和LF6铝合金异种材料的搭接连接,并对界面特性进行研究。采用所选取的工艺参数均能获得良好的表面成形,但每一种工艺参数下的界面形貌不同。随着焊接速度的增加或搅拌头转速的降低,被搅拌针搅入焊核区的钛合金粒子的数量减少,而且搭接接头的抗拉载荷也随着焊接速度的提高而降低。当焊接速度为60mm/min、搅拌头旋转速度为1500r/min时,接头的抗拉载荷达到最大值,此时的界面区可以分成三层。搭接接头的显微硬度分布不均匀,焊核中心区的显微硬度值最大,高达HV502。     

A Novel Friction Stir Spot Riveting of Al/Cu Dissimilar Materials

In order to eliminate the disadvantages of the keyhole in conventional friction stir spot welding joint and attain the high-strength lap joint of Al/Cu dissimilar metals,a novel welding technique,named as friction stir spot riveting(FSSR),was proposed.A pinless tool and an extra filling stud were employed.The Al/Cu spot joints without keyhole defect were achieved by the FSSR.A Cu anchor-like structure was formed,which greatly increased the mechanical interlocking between the upper Al sheet and lower Cu sheet.The thin intermetallic compounds containing CuAl2 and CuAl at the Al/Cu interface strength-ened the joining interface between the Al sheet and the Cu stud.Increasing rotating velocity increased frictional heat and plastic deformation and then eliminated the interfacial joining defects.The FSSR joint with the maximum tensile shear load of 3.50 kN was achieved at a rotating velocity of 1800 rpm and a dwell time of 20 s,whose fracture path passed through the softened region of upper Al sheet.In summary,the novel FSSR technique has the advantages of strong mechanical interlock-ing and metallurgical bonding between dissimilar materials,thereby attaining the high-strength spot joint.     

LF21超声搅拌摩擦焊接头组织及性能分析

利用超声波对金属塑性成形作用对LF21铝合金进行了超声搅拌摩擦焊接试验,并对常规搅拌摩擦焊与超声搅拌摩擦焊接头的微观组织、断口形貌进行了对比分析.结果表明,超声能量通过搅拌头有效地导入焊缝底部,在增加焊缝底部搅拌强度的同时,提高了搅拌针周围金属原子的运动和扩散能力,焊核区的金属组织有明显的晶粒细化和组织均匀化.超声搅拌摩擦焊断口韧窝数量与深度均不及常规搅拌摩擦焊,撕裂棱不明显;超声搅拌摩擦焊可以提高接头力学性能,但平均断后伸长率相比常规搅拌摩擦焊有所下降.     

温度峰值影响6061铝/AZ31B镁异种材料FSW接头成形的规律

以6061-T6铝合金与AZ31B镁合金为研究对象,基于Abaqus软件进行了异种材料搅拌摩擦焊过程的温度场数值模拟,重点分析搅拌针偏置镁侧下的搅拌区温度峰值影响焊缝表面成形的规律。结果表明,当焊接温度峰值高于Al-Mg共晶温度时,搅拌针根部附近区域会出现较明显的黏着现象,其随着焊接速度的降低而加剧,这与焊接温度峰值的升高相关。随着焊接速度的增加,焊缝表面更易避免裂纹缺陷的产生。当搅拌头的转速为1200r/min且焊接速度为40mm/min时,6061铝/AZ31B镁异种材料焊接接头的表面成形良好。     

Effect of Shoulder Size on Weld Properties of Dissimilar Metal Friction Stir Welds

This article reports a research study that shows the effect of shoulder diameter size on the resulting weld properties of dissimilar friction stir welds between 5754 aluminum alloy (AA) and C11000 copper (Cu). Welds were produced using three different shoulder diameter tools: 15, 18, and 25?mm by varying the rotational speed between 600 and 1200?rpm and the traverse speed between 50 and 300?mm/min to achieve the best result. Each parameter combination was chosen to represent different heat input conditions (low, intermediates and high). The welds were characterized through microstructural evaluation, tensile testing, microhardness measurements, x-ray diffraction analysis, and electrical resistivity. Microstructural evaluation of the welds revealed that the welds produced consisted of all the friction stir welding (FSW) microstructure zones with organized flow lines comprising mixture layers of aluminum (Al) and copper (Cu) at the Stir Zones. The average Ultimate Tensile Strength (UTS) of the welds considered ranged from 178 to 208?MPa. Higher Vickers microhardness values were measured at the joint interfaces of all the welds because of the presence of intermetallic compounds in these regions. The x-ray diffraction analysis revealed the presence of Al₄Cu₉ and Al₂Cu intermetallics at the interfacial regions, and low electrical resistivities were obtained at the joint interfaces. An optimized parameter setting for FSW of Al and Cu was obtained at the weld produced at 950?rpm and 50?mm/min with the 18-mm shoulder diameter tool.     

Friction stir welding of copper and copper alloys

Copper, through having good thermal conductivity and a relatively high melting point, generally requires preheating treatment to maintain satisfactory penetration during arc welding, ranking as a hard-to-weld material. Like aluminium and magnesium, however, copper is basically a soft metal and can therefore be relatively easily joined by friction stir welding. Available FSW research has focused on fabrication of copper (oxygen-free copper) containment canisters for nuclear waste,^1-6 fabrication of copper backing plates for sputtering devices by FSW seal welding,^{7, 8} and some other applications,⁹ whereas FSW research on copper alloys has thus far been little documented.^{10, 11} Related research topics include studies of Al alloy to Cu alloy dissimilar joints^{12, 13} as well as - although not quite the same as friction stir welding - friction stir processing of Ni-Al bronze for casting structure modification^14-16 and friction stir processing of a Cu-Mn alloy for surface modification purposes.¹⁷     

异种材料的搅拌摩擦焊技术

进行了铝合金与工业纯铜、铝合金与低碳钢的搅拌摩擦焊接实验.实际焊接了对接接头、丁字接头、搭接接头,观察了焊接接头组织,测量了接头性能.结果表明,用搅拌摩擦焊方法代替熔化焊方法焊接异种材料,可以获得组织致密、无缺陷的接头,接头强度较高,且工艺适应性、结构适应性较好,焊接工艺参数、各组元在焊缝金属中的比例等对形成良好的焊缝有重要的影响.     

铝-钢堆焊-搅拌摩擦复合焊接头特性分析

针对铝-钢异种金属焊接缺陷多、效率低等问题,提出一种堆焊-搅拌摩擦复合焊接方法,即采用旁路分流电弧焊先在钢板上堆敷铝合金,再采用搅拌摩擦焊进行铝合金堆敷层和铝合金母材的搭接焊,得到在铝-铝界面呈现典型搅拌摩擦焊“洋葱圆环”状结合的铝-铝-钢复合过渡接头. 针对典型焊缝进行铝-钢异种金属接头的组织结构分析.结果表明,搅拌摩擦焊可以有效消除铝合金堆敷层中存在的气孔等缺陷,并实现金属界面层的减薄. 对铝钢结合界面进行EDS扫描,在堆敷铝合金侧可以观察到呈树枝状的Fe相扩散和呈网状的不均匀Si相扩散,结合XRD(X-ray diffraction)分析其主要成分为Al₅Fe₂Zn_0.4和Al₇Fe₃Si_0.3. 对接头试样进行拉伸试验,拉伸接头断裂在铝合金母材处,达到铝合金母材强度的100%,符合接头应用的力学指标.     

Dissimilar Joining of Pure Copper to Aluminum Alloy via Friction Stir Welding

In this study, the dissimilar friction stir welding(FSW) butt joints between aluminum alloy 5754-H114 and commercially pure copper were investigated. The thickness of welded plates was 4 mm and the aluminum plate was placed on the advancing side. In order to obtain a suitable flow and a better material mixing, a 1-mm offset was considered for the aluminum plate, toward the butt centerline. For investigating the microstructure and mechanical properties of FSWed joints, optical microscopy and mechanical tests(i.e., uniaxial tensile test and microhardness) were used, respectively.Furthermore, the analysis of intermetallic compounds and fracture surface was examined by scanning electron microscopy and X-ray diffraction. The effect of heat generation on the mechanical properties and microstructure of the FSWed joints was investigated. The results showed that there is an optimum amount of heat input. The intermetallic compounds formed in FSWed joints were Al4Cu9 and Al2Cu. The best results were found in joints with 1000 rpm rotational speed and100 mm/min travel speed. The tensile strength was found as 219 MPa, which reached 84% of the aluminum base strength.Moreover, maximum value of the microhardness of the stir zone(SZ) was attained as about 120 HV, which was greatly depended on the grain size, intermetallic compounds and copper pieces in SZ.     

铝合金搅拌摩擦焊的研究现状与展望

在介绍搅拌摩擦焊技术的基本原理及影响因素的基础上,综述了铝合金搅拌摩擦焊在接头金属塑性流动、显微组织以及性能等方面的国内外研究现状.研究现状表明,搅拌头形状和工艺参数对接头组织和性能具有重要影响,在合适的工艺参数下可获得综合性能良好的铝合金搅拌摩擦焊接头,并取得了一定规模的应用.此外,指出了搅拌摩擦焊技术的不足和接头性...     

Influence of tool pin design on properties of dissimilar copper to aluminum friction stir welding

Dissimilar friction stir welding (FSW) of copper and aluminum was investigated by nine different tool designs, while the rest of the process parameters were kept constant. Mechanical and metallurgical tests such as macrostructure, microstructure, tensile test, hardness, scanning electron microscope and electron X-ray spectrographs were performed to assess the properties of dissimilar joints. The results exhibited that, the maximum joint strength was achieved by the tool of cylindrical pin profile having 8 mm pin diameter. Besides, the fragmental defects increased as the number of polygonal edges decreased, hence the polygonal pin profiles were unsuitable for dissimilar FSW butt joints. Furthermore, the tensile strength increased as the number of polygonal edges increased. Stir zone of polygonal pin profiles was hard and brittle relative to cylindrical tool pin profiles for same shoulder surface. Maximum hardness of HV 283 was obtained at weld made by the polygonal square pin profile. The hard and brittle intermetallic compounds (IMCs) were prominently presented in the stir zone. Phases of IMCs such as CuAl, CuAl₂, Cu₃Al and Cu₉Al₄ were presented in the stir zone of dissimilar Cu–Al joints.     

Enhancing metallurgical and mechanical properties of friction stir lap welding of Al–Cu using intermediate layer

Abstract

In this paper, the material behaviour and mechanical characteristics of lap joint friction stir welding (FSW) between dissimilar alloys, namely, Cu and Al, is investigated. In order to produce welds of a higher quality, a layer of Cu is anodised on the aluminium alloy. The mechanical and the microstructural characterisations are performed on the welds, which are produced using various welding parameters. Scanning electron microscope with energy dispersive X-ray spectroscopy is used to identify the elemental compositions of phases that are formed. The results reveal that the use of the copper anodised layer prevented formation of brittle intermetallic compounds due to the direct FSW of 6061 aluminium alloy to copper and, as a result, enhanced the weld metallurgical and mechanical properties.     

Friction stir welding of co-cast aluminium clad sheet

The effects of welding parameters on material consolidation are examined during friction stir butt welding of 2 mm Al 5083 alloy aluminium sheet with a surface cladding of Al 3025 alloy, which was co-cast from the melt. The influence of welding parameters on joint consolidation is investigated when tool revolutions per minute, travel speed and penetration depth were varied. It was found that modifying the pin of the welding tool to have a two-flat profile improves material consolidation and avoids defect formation during welding, and optimum welding parameters involve a combination of high tool rotation speed and travel speed. Optical and electron microscopy revealed that the integrity of the surface cladding layer could be maintained during friction stir welding while avoiding defect formation within the stir zone of the weld. The tensile strength of the joint was ～58% of the base material due to softening within the stir zone.     

外加热源对铝-铜搅拌摩擦焊对接的影响

为了改善铝-铜搅拌摩擦焊对接接头的焊缝接头性能,文中采用对焊缝铜一侧引入外加热源的方法,来增加焊接热输入,提高铜侧材料的软化程度.结果表明,外加热源能够有效提高焊缝部位铜一侧的焊接温度,从而增加焊接过程中铜一侧的塑化流动性,形成成形良好的焊接接头.通过焊缝的物相对比可知,外加热源引起的温度场的改变,有效地减少了焊缝中CuAl,CuAl₂等中间相的含量,增加了铜颗粒在焊缝中的含量.在力学性能上表现为有外加热源的焊缝拉伸强度较高,显微硬度分布均匀.