铝合金/不锈钢惯性摩擦焊接头的组织特性和力学性能研究（英文）

惯性摩擦焊是一种连接异种金属理想的焊接方法,对铝合金/不锈钢采用惯性摩擦焊进行焊接,并详细研究了焊接接头的形貌、组织、界面成分和力学性能。结果表明,在惯性摩擦焊接头的界面处形成了很薄的金属间化合物(IMC)反应层,该反应层主要由Al、Fe元素组成,是富集Si元素的Fe Al3相。惯性摩擦焊接头组织由焊核区、完全动态再结晶区、热机械影响区和热影响区组成。完全动态再结晶区的晶粒尺寸小于0.1μm,它的平均宽度为5μm。接头的显微硬度(HV)最大值出现在不锈钢侧的完全动态再结晶区,其值为3958 MPa。惯性摩擦焊中,初始转速对接头的拉伸性能有显著影响。当初始转速为1200 r/min时,铝/钢惯性摩擦焊接头的最大抗拉强度为323 MPa,达到铝合金母材强度的92%。     

铝/钢异种金属旋转摩擦焊接研究现状

根据铝/钢异种金属焊接冶金特点及旋转摩擦焊接工艺特点,分析认为旋转摩擦焊最适合铝/钢异种金属轴对称件焊接的工艺。分别介绍了连续驱动摩擦焊和惯性摩擦焊接工艺对铝/钢异种金属焊接接头的组织和性能的影响。总结了铝/钢异种金属摩擦焊接技术研发中亟待解决的主要科学问题,铝/钢旋转摩擦焊过程中摩擦界面及其附近剧烈的塑性流变对IMCs生成的影响规律和机制需要进一步的研究;需要开发相应的工艺措施促进铝/钢接头界面上形成以Fe-Al IMCs为标志的冶金结合,并使IMCs层厚度均匀化。最终指明,研究揭示铝/钢摩擦界面IMCs生成机理、相的组成、形态、分布等冶金行为,对铝/钢旋转摩擦焊接头的组织性能调控具有重要意义,也是铝/钢异种金属焊接结构性能保证的理论基础。     

异种合金惯性摩擦焊的研究现状

文中针对钢与其他合金、铝合金与其他合金、钛合金与其他合金、高温合金与其他合金的惯性摩擦焊的研究现状进行了阐述。主要对惯性摩擦焊的工艺参数选取、端面设计、焊前预热、焊后热处理等研究内容进行了综述。并对异种合金惯性摩擦焊存在的问题进行了分析总结。结果表明,采用合理选择工艺参数、设计不同形状的端面、添加中间过渡层、焊前预热处理、焊后热处理等方法获得强度与母材相当、焊接质量较好的接头。建议在后续的研究中,结合数值模拟对异种合金惯性摩擦焊的工艺参数及端面设计进行优化,对接头的元素分布及新相形成的种类与数量进行调控,对焊接界面金属的流动行为进行深入研究,以获得具有综合性能较好的异种合金惯性摩擦焊接头。     

抽油杆摩擦焊接头组织和性能

对抽油杆摩擦焊接头的形成过程、金属流线的走向、金相组织、硬度分布等方面进行了分析.材料合金元素和焊后热处理方式直接影响到焊接接头的组织和性能,利用显微硬度测试的方法,对抽油杆摩擦焊接头各部位进行硬度检测、冲击试验,揭示了摩擦焊接头不同部位组织、性能的分布规律.     

Ti和Fe连续驱动摩擦焊焊接界面宏观变形及微观形貌研究

为了给钛/钢连续驱动摩擦焊制造提供理论支撑,采用钛和钢主体元素的纯钛和纯铁进行连续驱动摩擦焊试验,研究了焊接时间和摩擦压力对界面宏观变形和组织演变的影响规律。试验结果表明:随着摩擦压力的增大,界面宏观变形增大。随着焊接时间的增加,界面宏观变形变化不大。焊接界面两侧组织细化明显,Fe侧由细小的铁素体晶粒组成,Ti侧由细小的α晶粒组成。塑性层厚度随摩擦压力增加而增加,且近似为线性关系,焊接时间对塑性层厚度影响不大。     

K418涡轮盘与42CrMo轴异种材料惯性摩擦焊研究

采用惯性轴向摩擦焊技术对镍基K418高温合金与42CrMo调质钢两种异种材料进行了焊接工艺试验,并分析焊接接头的显微组织,测试其力学性能.结果表明,惯性摩擦焊过程中发生摩擦面转移现象,碳原子扩散导致K418侧含有少量非连续网状碳化物,焊接界面两侧硬度均匀过渡,焊接接头抗拉强度均在750 MPa以上,整体抗拉强度高,获得了优良的焊接接头,惯性摩擦焊工艺适合于焊接异种材料.     

电子束焊-钎焊复合焊T形接头组织性能分析

实现了TA15钛合金T形接头的电子束焊-钎焊复合焊接.采用扫描电镜、能谱分析仪和X射线衍射分析仪等测试手段,对接头的微观组织形貌、元素成分分布和界面反应产物等进行分析研究.并分别对复合焊接头和电子束焊接头的弯曲性能进行了比较分析.结果表明,在适当的工艺条件下,可以实现TA15钛合金T形接头的电子束-钎焊复合焊接.在电子束焊缝和钎焊缝的界面处存在Cu,Ni元素的扩散和界面反应.复合焊接头的塑性要优于电子束焊,其所承受的最大压强略低于电子束焊.     

铝/钢异种金属火焰钎焊接头组织和性能

通过扫描电镜、能谱分析和X射线衍射等方法研究了火焰钎焊时Zn-xAl钎料的润湿性能、铝/钢钎焊接头界面显微组织、金属间化合物层以及接头抗剪强度.结果表明,Zn-xAl钎料配合改性CsF-RbF-AlF₃钎剂,可以有效地去除母材表面氧化膜,从而提高钎焊接头力学性能.随着Al元素含量增加,钎料铺展性和填缝性随之提高,但是钎焊接头强度先升后降,Al元素含量为15%时,钎焊接头力学性能最佳.钎焊接头显微组织分析结果表明,金属间化合物主要为Fe₄Al₁₃相. Zn-xAl钎料中Al元素含量较低时,界面层由富锌相和Fe₄Al₁₃相组成.随着Al元素含量的增加,在Zn-25Al钎焊接头界面出现第二层金属间化合物Fe₂Al₅相.     

摩擦增材辅助Ti/Al搅拌摩擦搭接接头特征分析

为解决Ti/Al异种材料搅拌摩擦焊接接头强度低、搅拌针磨损等问题,提出一种摩擦增材辅助搅拌摩擦搭接焊(friction addition-friction stir lap welding, FA-FSLW)技术. 该新工艺延续了固相连接的优势,具有热输入量低、界面金属间化合物薄等特点.文中研究了以6082铝合金作预沉积层辅助实现3 mm厚2A12铝合金板与4 mm厚TC4钛合金板之间的连接,焊接过程中搅拌头扎入铝沉积层而不接触钛表面,得到抗拉载荷最大为12.2 kN的接头.结果表明, FA-FSLW复合焊接头的界面迁移越大,接头承载越小.同时,发现界面处的Ti, Al元素发生了明显互扩散,Si元素在界面偏聚,与Ti, Al元素发生冶金反应后形成层状纳米级Ti-Al-Si金属间化合物,为提高接头强度奠定基础.     

惯性摩擦焊接头非对称性分析

应用无线测温系统和热电偶测温技术,试验测定了惯性摩擦焊旋转端和滑移端试件的温度场,探讨了惯性摩擦焊摩擦界面两侧温度分布的非对称性;统计分析了不同焊接条件下惯性摩擦焊试样焊接区域的几何特征及宏观形貌.结果表明,滑移端的温度及升温速率均高于旋转端,滑移端的轴向缩短量、飞边宽度以及热力影响区(TMAZ)宽度均大于旋转端.分析认为惯性摩擦焊摩擦结合界面两侧温度场的非对称性与焊接区域几何特征的非对称性紧密相连.     

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.     

Effects of processing parameters on the friction stir spot joining of Al5083-O aluminum alloy to DP590 steel

Two dissimilar materials, aluminum alloy Al5083-O and advanced high strength steel DP590, were successfully joined by using friction stir spot joining (FSSJ). Satisfactory joint strengths were obtained at a rotational speed of 300 rpm and a plunge depth of 0.7 mm. Resulting joints were welded without a non-welded zone. This may be attributed to the enhanced smooth material flow owing to sufficient stirring effect and tool down force between the upper Al5083-O side and the lower DP590 side. The maximum tensile shear strength was 6.5 kN, which was higher than the joint strength required by the conventional method of resistance spot welding. The main fracture mode was plug fracture in the tensile shear test of joints. An intermetallic compound (IMC) layer with <6 μm thickness was formed at the joint interface, which meets the allowance value of <10 μm for the dissimilar material Al-Fe joints. Thus, the use of FSSJ to weld the dissimilar materials Al5083-O and DP590 resulted in mechanically and metallurgically sound joints.     

焊接速度对高强铝合金搅拌摩擦焊接头组织及力学性能的影响

焊接速度对搅拌摩擦焊接头内焊核区、热机影响区和热影响区组织和晶界沉淀相均有较大的影响。随着焊接速度的提高,焊核区和热影响区内的晶粒尺寸和沉淀颗粒大小、分布密度变化均较大;热机影响区内组织的变形程度变化明显。组织和力学性能综合分析表明,控制焊接速度。获得优良的焊核区组织有利于提高接头的力学性能。性能测试结果表明,焊接速度v=37．5mm／min时,2Al2CZ铝合金接头强度达到最大值(331MPa)。     

焊接工艺参数对钢/铌激光焊接头性能的影响

采用正交试验法分析了焊接工艺参数对钢/铌激光焊接头抗拉强度的影响规律.结果表明,接头抗拉强度随着焊接速度的增大而降低;随着激光束从铌侧向钢侧偏移,接头强度逐渐升高;激光功率对接头强度的影响不大.在3个焊接工艺参数中,偏束距离对接头强度的影响最大,焊接速度次之,激光功率的影响最小.采用低焊接速度、向钢侧偏束的焊接方法可以提高焊接接头的抗拉强度.焊缝区主要包括铌侧的IMC区,焊缝中心的树枝晶区与钢侧的树枝晶区三个特征区.其组织由大量的γ奥氏体相与一定量的Fe₂Nb相及少量的δ铁素体相组成.铁-铌金属间化合物的生成是降低接头强度的主要原因.     

球墨铸铁与45钢的摩擦焊接研究

球铁与 45钢采用摩擦焊接方法可形成良好的焊接接头。焊后退火处理可改善球铁 - 45钢摩擦焊接头的组织 ,提高接头的性能。在其他焊接参数保持不变时 ,退火后接头拉伸强度随摩擦时间的增大而增加 ,直到 2 3s时达到最大值 358MPa,继续增大摩擦时间 ,接头拉伸强度下降。这主要是因为摩擦时间直接影响着球铁与 45钢摩擦焊接过程中的产热、温度分布、金属的塑性变形和石墨在界面的形态。     

Dissimilar metal joining of aluminum alloy to galvanized steel with Al-Si, Al-Cu, Al-Si-Cu and Zn-Al filler wires

Aluminum alloy sheets were lap joined to galvanized steel sheets by gas tungsten arc welding (GTAW) with Al-5% Si, Al-12% Si, Al-6% Cu, Al-10% Si-4% Cu and Zn-15% Al filler wires. Different amounts of Si, Cu and Zn were introduced into the weld through different filler wires. The effects of alloying elements on the microstructure in the weld and tensile strength of the resultant joint were investigated. It was found that the thickness of the intermetallic compound (IMC) layer decreased and the tensile strength of the joint increased with the increase of Si content in the weld. The thickness of the IMC layer could be controlled as thin as about 2 μm and the tensile strength of the dissimilar metal joint reached 136 MPa with Al-12% Si filler wire. Al-Si-Cu filler wire could result in thinner interfacial layer than Al-Cu filler wire, and fracture during tensile testing occurred in the weld for the former filler wire but through the intermetallic compound layer for the latter one. A Zn-rich phase formed in the weld made with Zn-15% Al filler wire. Moreover, the Zn-Al filler wire also generated thick interfacial layer containing a great amount of intermetallic compounds and coarse dendrites in the weld, which led to a weak joint.     

W6高速钢/16Mn钢电子束焊接接头组织及性能分析

高速钢作为一种高硬度、高耐磨性和高耐热性特殊工具钢,应用于刀具、模具及特殊结构件上时,往往需要结合异种钢使用. 但高速钢焊接工艺研究仍不成熟,焊接中产生的裂纹与碳化物缺陷是制约高速钢应用的主要因素. 文中通过对W6Mo5Cr4V2高速钢与16Mn钢预置镍填充层后进行电子束焊接. 结果表明,镍中间层的引入有效的抑制了高速钢侧热影响区的开裂,接头呈不对称“漏斗形”. 焊缝组织主要由镍基固溶体与少量M₂C碳化物构成,焊缝中无马氏体组织,其焊缝平均硬度为185 HV;接头抗拉强度达到378 MPa,为16Mn侧母材抗拉强度的75%. 拉伸断口断裂于距W6侧熔合线0.8 mm处的热影响区,为准解理断裂.     

Interface properties and thermodynamic analysis of laser–arc hybrid welded Al/steel joint

Abstract

Fibre laser–cold metal transfer hybrid welding was introduced to join AA 6061 aluminium alloy with AISI 304 stainless steel using Al–12Si filler wire. Interface properties and microstructure of welded joints were observed by optical microscope, scanning electron microscope, energy dispersive spectrometry and X-ray diffraction techniques. A serrated intermetallic compound (IMC) layer was found at the interface between fusion zone and stainless steel. The morphology of IMC layer was uniform from the top to the bottom, and its average thickness was 3 μm. The IMC layer consisted of two layers: Al₈(Fe,Cr)₂Si layer close to fusion zone and (Al,Si)₁₃Fe₄ layer close to stainless steel. The joint fractured at the IMC layer and presented a tensile strength of 165 MPa. The formation of the IMC layer was closely related with the thermodynamic and kinetic behaviours of the interface and fast cooling rate of hybrid welding.     

7050铝合金搅拌摩擦焊接头微观组织及力学性能分析

采用搅拌摩擦焊焊接厚12 mm的7050铝合金,分析接头的微观组织和力学性能。研究结果表明,焊核区由于热循环作用形成细小的等轴再结晶组织;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,在热循环的作用下发生回复反应;热影响区仅受热循环的作用,组织稍微有粗化现象。力学试验表明:旋转速度400r/min、焊接速度180mm/min时,接头的抗拉强度可以达到391 MPa,为母材的77%;焊接速度200 mm/min,旋转速度450 r/min时,接头的抗拉强度可以达到376 MPa,为母材的74%。断口形貌分析显示,接头断裂模式为穿晶和沿晶混合型断裂。     

纯铝1060/镀锌钢电阻点钎焊工艺及接头性能

采用电阻点钎焊进行了纯铝1060与SGCC热镀锌钢板的搭接试验,研究了接头界面组织,并测试了接头力学性能. 结果表明,试验所用铝硅（Al-Si）合金钎料润湿良好,焊后接头焊缝界面处产生了具有双层结构且厚度不均的金属间化合物,厚度小于10 μm;焊接电流为7.8 kA时,接头抗拉剪载荷达到峰值,约为4.72 kN,在相同工艺参数下,电阻点钎焊接头的抗拉剪载荷明显高于点焊接头;接头断裂大都发生在铝板侧,且主要在热影响区处而不在焊点处,说明点钎焊接头质量良好,但由于焊缝铝侧界面局部存在“未钎合”缺陷,焊缝界面会产生拉应力且在金属间化合物的应力作用下易产生裂纹.