保压腔对异种金属摩擦焊擦过程的影响

两种强度相差较大的异种金属进行摩擦焊接时，使用保压腔是克服由于软金属的大量塑性变形而给焊接过程带来困难的有效手段之一。本文研究了保压腔参数的变化对摩擦压力和摩擦扭矩的影响规律，并在合适的保压腔参数下得到了高强度的紫铜的焊接接头。     

保压腔对异种金属摩擦焊中摩擦过程的影响

两种强度相差较大的异种金属进行摩擦焊接时，使用保压腔是克服由于软金属的大量塑性变形而给焊接过程带来困难的有效手段之一。本文研究了保压腔参数的变化对摩擦压力和摩擦扭矩的影响规律，并在合适的保压腔参数下得到了高强度的紫铜和纯铝的焊接接头。     

铁基粉末冶金摩擦焊接头分析

摩擦焊是一种固相连接方法，以其优质、离效、低耗环保的突出优点得到了广泛的应用。半个世纪的推广应用，证明了摩擦焊在简化结构和工艺、减少加工、提高质量、降低成本等方面具有独特的效果和显著的作用。摩擦焊不仅可焊接钢、铝、铜．还成功地焊接了高温强度级相差很大的异种金属。随着汽车、飞机及电气制造等部门大量采用粉末冶金材料，国外已采用摩擦焊方法成功地焊接了耪末冶金材料，但目前国内尚无这方面的报道。在此，通过优选工艺参数．成功地焊接了铁基粉末冶金材抖。     

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.     

2024-T4铝合金超声辅助搅拌摩擦焊接头组织与性能研究

沿搅拌头方向将超声能量引入对接焊焊缝,利用超声波的振动作用,促进搅拌针周围金属原子的运动和扩散能力,能有效地细化和均匀化焊核区的金属组织,改善焊缝材料的塑性流变行为,增强焊缝底部的搅拌强度,提高搅拌摩擦焊焊接质量和焊接效率。通过对1.8 mm厚2024-T4铝合金进行平板对接焊试验,对比研究了搅拌摩擦焊焊接接头组织与性能。结果表明,超声辅助搅拌摩擦焊能有效减少焊接缺陷,并且接头强度提高了10%,超声辅助搅拌摩擦焊优越性效果明显。     

钛合金与铝合金异种金属焊接的研究现状

对钛/铝异种金属焊接过程中脆性Ti-Al金属间化合物的控制方法进行了综述，介绍了熔化焊(激光焊、电子束焊)、钎焊、熔钎焊、扩散焊、搅拌摩擦焊及爆炸焊的研究现状，并对存在的问题与发展趋势进行了讨论。结果表明，钛/铝焊缝中极易形成脆性的Ti-Al金属间化合物，导致钛/铝接头强度的降低。在激光焊、电子束焊过程中，通过热源偏移的方式可以降低Ti-Al金属间化合物含量；采用合理的中间层，既能降低Ti-Al金属间化合物的含量又能形成塑性更好的金属间化合物。采用熔钎焊工艺并选用合适的填充材料，可以有效地抑制Ti-Al金属间化合物的生成。采用扩散焊工艺、通过添加中间层、在钛表面渗铝及合理控制工艺参数，能有效减少Ti-Al脆性金属间化合物的生成，但接头的抗拉强度不高。采用搅拌摩擦焊并通过添加中间层抑制钛/铝接头中Ti-Al脆性金属间化合物的形成，获得性能良好的钛/铝接头，但会受到焊件的形状的影响。采用爆炸焊工艺，可以细化界面中的金属颗粒，提高钛/铝接头的强度。     

材料性能对铝合金搅拌摩擦焊焊缝成形的影响

采用自主设计的左螺纹圆柱形搅拌头对1060纯铝、5A06和7075铝合金进行同种及异种材料搅拌摩擦焊试验,研究了材料性能对搅拌摩擦焊焊缝成形的影响。试验结果表明:由于材料性能不同,焊缝周边金属对焊缝塑性金属的约束状态不同,从而改变焊缝形貌。同种材料对接时,随着材料强度硬度的增加,焊缝周边金属对焊缝塑性金属的约束力增大,焊核直径和焊核面积逐渐减小。异种材料对接时,在焊接热输入相同的情况下,搅拌针表面螺纹与强度硬度低的金属材料过早地发生滑动摩擦导致驱动力不足,焊核宽度和面积更小,焊核中心向强度硬度高的材料一侧偏移。     

GH4169线性摩擦焊接头的焊合率与弯曲强度

论述了高温合金GH4169线性摩擦焊的试验过程。分析了弯曲强度、断裂挠度与焊合率之间的关系及接头的金相组织。结果表明,GH4169线性摩擦焊接头的弯曲强度与焊合率成正比线性关系,断口为韧性断口;断裂强度受摩擦时间的影响较大。     

1060／3003铝合金搅拌摩擦焊焊接接头材料流动规律研究

搅拌摩擦焊中，材料的流动状态对焊件性能有很大影响。对5mm厚的1060／3003铝合金板材进行了搅拌摩擦焊连接。通过对1060／3003铝合金焊件焊核区腐蚀，研究了焊核区金属的流动形态。分析了不同工艺参数下垂直截面和水平截面的金属流动形态。结果表明：工参数对搅拌摩擦焊焊核区金属的流动形态有很大影响。通过使用较高的工具旋转速度和合适的焊接速度可以获得稳定、质量良好的搅拌摩擦焊接头。     

铝合金搅拌摩擦焊焊核紊流区及性能分析

采用搅拌摩擦焊方法对2219-T6铝合金进行焊接,对焊接接头的宏观形貌、微观组织、抗拉强度进行了分析,并通过对焊核塑性金属的流动状态进行分析,研究了搅拌摩擦焊接头强度弱化的原因. 结果表明,焊核根据流态可分为3个不同的区域,其中靠前进侧存在一个性能薄弱的B区域,该区的产生是抽吸挤压作用不平衡的结果,也是塑性金属向上回流通道. 该区具有较大的塑性损伤,易产生疏松缺陷及界面突变,晶粒具有较大的热不稳定性,是造成接头强度低于母材的主要原因之一. 通过高温短时的再结晶热处理工艺可以恢复该区域的强韧性,消除弱化问题.     

Dissimilar friction welding of aluminium alloys to other materials

Friction welding makes it easier to set welding conditions and also confers greater reproducibility than other welding processes. Through being a solid-phase process, friction welding moreover makes it relatively easy to join dissimilar materials. Other advantages of friction welding include good operability, the lack of any need for special skills, and a convenient capability for incorporation in assembly lines without showers of sparks and similar hazards being generated. Friction welding is therefore extensively used in a wide variety of industries, such as automotive engineering, printing, etc. Joining of dissimilar materials as a characteristic friction welding application has been well researched,¹ reported,² and thoroughly explained with reference made to practical examples.³ In the current situation of materials development advancing apace in pursuit of various objectives, available data relating to joining of dissimilar materials remains scant. To meet resource- and energy-saving objectives, machinery and plant, transport machinery, etc. are now required to embody lighter weight in a well-established trend that can only serve to expand the use of light metals. Compared with ferrous metals, however, friction welding of light metals has been little documented.     

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...     

Role of nickel as an interlayer in dissimilar metal friction welding of maraging steel to low alloy steel

Continuous drive friction welding of dissimilar metals, maraging steel and low alloy steel was carried out. It was observed that the hardness, ductility and impact toughness of maraging steel are low due to the diffusion of elements such as carbon, manganese, silicon and phosphorus from low alloy steel to maraging steel. An attempt was made in this study to improve the properties by friction welding of maraging steel and low alloy steel with nickel as an interlayer. The hardness, tensile strength and impact toughness are observed to be improved, as nickel acted as diffusion barrier. The effect of post-weld heat treatments on microstructure and mechanical properties of dissimilar metal friction welds with and without interlayer was also studied. Maraging steel responded to solutionizing & aging and low alloy steel responded to quenching and tempering. The notch tensile strength and impact toughness in case of dissimilar metal weld with interlayer are observed to be more than that of the dissimilar metal weld without interlayer.     

Similar and dissimilar friction welding of Zr–Cu–Al bulk glassy alloys

The friction welding of three kinds of Zr–Cu–Al bulk glassy alloys (BGAs) which show eutectic or hypoeutectic compositions to similar and dissimilar BGAs and crystalline metals has been tried. The shape and volume of the protrusion formed at the weld interface were investigated. In order to characterize the friction welded interface, micrographic observation and X-ray diffraction analysis on the weld cross-section were carried out. A successful joining of Zr–Cu–Al bulk glassy alloys to similar and dissimilar BGAs was achieved without occurrence of crystallizations at the weld interface through the precise control of friction conditions. In addition, the joining of Zr₅₀Cu₄₀Al₁₀ BGA to crystalline alloys was tried, but it was only successful for specific material combinations. The residual strength after welding of dissimilar BGAs was evaluated by the four-point bending test.     

TC4/T2连续驱动摩擦焊工艺及接头组织与性能

采用连续驱动摩擦焊实现了TC4/T2异种金属之间的焊接. 结果表明,热物理性能差异显著的TC4和T2异种金属之间连续驱动摩擦焊,宜采用强规范工艺条件,即采用较大的焊接压力,较短的焊接时间;TC4/T2连续驱动摩擦焊头形成非对称飞边,摩擦压力过小,焊接热输入不足,难以形成规则的飞边形态;采用较短的I级摩擦焊接时间,可以形成紧密的TC4/T2冶金结合界面,并形成一定程度的机械咬合. TC4/T2连续驱动摩擦焊最佳工艺参数为:Ⅰ级加压、Ⅱ级加压和顶锻压力在试样表面产生的压强分别为1.4,1.8和2.1 MPa,Ⅰ级摩擦焊接时间为5 s. 采用最佳焊接工艺参数,TC4/T2连续驱动摩擦焊接头抗拉强度达到母材T2的96.7%.     

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.     

大截面钢/铝摩擦焊接头力学性能及显微组织分析

针对大截面铸态纯铝与Q235钢异种金属.采用连续驱动摩擦焊技术进行焊接试验,通过光学显微镜观察、电子探针分析、常温和高温拉伸性能及硬度测试,探讨了其焊接接头的微观组织和力学性能.研究表明,大截面铸态纯铝与Q235钢间具有良好的摩擦焊接性,焊接接头强度等于或高于铝基材;高温条件下,试样均断于铝端母材,抗拉强度随着温度的升高呈现出明显的下降趋势,而伸长率随温度升高而增大;焊接接头在近缝区发生了晶粒细化,在粘塑性层内发生了一定程度的原子扩散,形成扩散层.     

Friction welding of molybdenum to molybdenum and to other metals

This paper presents the result of investigations into the friction welding of similar-metal and dissimilar-metal (vanadium, tantalum, niobium, titanium and copper) combinations of molybdenum and molybdenum alloy (TZM). The produced joints were subjected to microscopic examination, microhardness tests and strength tests. It has been found that refractory metals can be joined by friction welding. The friction welded joints had proper microstructures with no intermetallic phases. Friction welding parameters proper for welding TZM to other metals have been determined. The parameters can be used for the direct welding of TZM to other metals and for the welding of interlayers.     

State of the art about dissimilar metal friction stir welding

Friction stir welding is a rather recent welding process (patented in 1991 by Thomas et al., ‘Improvements to friction welding’ UK patent application no. 9125978.8, US Patent 5460317, 1995) that has shown great potential for welding dissimilar materials even of different metallic nature, e.g. Al to steel, Mg to steel, Al to Ti, Mg to Ti, Al to Cu, Al to Mg. This review presents the specific microstructural features and mechanical properties, in particular tensile strength, of such welds. A focus will be on the material flow and welding defects, on the intermetallic compounds, on constitutional liquation, on particularities related to dissimilar lap welding and finally on process modifications to improve dissimilar friction stir weldability.