铝 / 钢异种金属搅拌摩擦焊及其研究进展

铝/钢异种金属连接结构在国防领域和国民生产、生活中更加广泛应用的前提,是获得良好的接头综合性能,但铝/钢焊接时易出现裂纹、金属间化合物等,严重影响了焊接接头质量。摩擦焊作为一种低温高效的固相连接方法,在新材料连接、高性能装备制造等领域受到了高度重视。其中,搅拌摩擦焊由于其可焊接头形式丰富而被重点关注。从搅拌摩擦焊的接头形式、工艺参数、力学性能及界面组织4个方面,分别介绍了铝/钢搅拌摩擦焊的研究进展,为其深入研究提供依据。     

汽车轮辋用钢搅拌摩擦焊接头组织及力学性能

目的 为搅拌摩擦焊在轮辋钢的应用提供理论数据。方法 选用厚度为4.5 mm的江铃汽车V362轮辋钢板B380CL,采用不同的焊接参数,获得搅拌摩擦焊接头,对焊缝宏观成形及微观组织进行分析,研究焊接参数对组织的影响;通过进行拉伸试验和硬度测试,分析焊接参数对焊接接头性能的影响;对接头焊缝进行X-Ray无损探伤。结果 当搅拌头旋转速度为950 r/min,焊接速度分别为37.5, 47.5, 60 mm/min时,均能形成焊接接头。焊接速度为47.5 mm/min时,焊缝宏观成形较好,微观组织无缺陷,微观组织为铁素体和珠光体,抗拉强度最高,超过母材;焊接接头各区域微观组织硬度较母材高,伸长率较焊接速度为37.5 mm/min时的接头高。结论 搅拌摩擦焊实现轮辋钢的对接,该研究中旋转速度950 r/min,焊接速度47.5 mm/min为最佳工艺参数,接头抗拉强度超过母材。     

异种铝合金搅拌摩擦焊接接头的微观组织与力学性能

采用搅拌摩擦焊方法对4mm厚的5083铝合金与6082铝合金进行了焊接,对焊接接头的微观组织和力学性能进行了分析。结果表明,焊核区由细小的等轴再结晶组织构成,6082铝合金在前进侧的抗拉强度大于5083铝合金在前进侧的抗拉强度,正弯试验与背弯试验角度都达到180°。     

铝合金搅拌摩擦焊接头微观组织和力学性能分析

目的 研究7020铝合金搅拌摩擦焊(FSW)的结构和机械性能。方法 采用搅拌摩擦焊对铝板进行对接焊试验,具体形式为单面焊双面成型。采用拉伸机和显微维氏硬度仪对试样进行力学性能测试;利用蔡司金相、光谱仪、扫描电子显微镜、X射线衍射仪研究母材和焊接接头的微观组织。结果 在硬度上,母材>热影响区>焊核区,热影响区平均硬度约为94HV,母材平均硬度为99HV,焊核区平均硬度最低为78HV,焊核区出现“S”缺陷,在一定程度上弱化了焊核区性能;7020铝合金搅拌摩擦焊接头的抗拉强度为235 MPa,屈服强度为158 MPa,屈强比为0.67,伸长率为7%,焊接系数可以达到73.8%;母材的抗拉强度为325 MPa,屈服强度为278 MPa,屈强比为0.86,伸长率为25%;焊接接头中心显微组织主要由胞状树枝晶体组成,显微结晶依次呈现为平面晶、胞状晶、树枝状晶、等轴晶;铝合金母材和焊接接头的金属相组成均为α?Al+Mg2Si;焊接接头断口呈现比较明显的韧性断裂特征。结论 铝合金搅拌摩擦焊可以获得性能比较优良的焊接接头,为其他铝合金材料的FSW焊接提供技术参考。     

转速对铝铜异种材料水下搅拌摩擦焊接接头组织与性能的影响

采用水下搅拌摩擦焊接(submerged friction stir welding,SFSW)技术对2024-T4铝合金和紫铜进行连接,研究转速对接头微观组织与力学性能的影响。结果表明:接头成型良好,无裂纹、孔洞等缺陷。随转速升高,接头表面平整度提高,大量铜被卷入焊核区(nugget zone,NZ),NZ组织结构逐渐混乱。SFSW过程中,冷却水有效抑制了晶粒粗化和脆性金属间化合物生成。当转速为750r/min时,接头抗拉强度为227MPa,达到铜母材的70.3%,随转速增大,接头的抗拉强度和伸长率降低。     

6016-T4铝合金与镀锌IF钢搅拌摩擦焊接头的组织与性能

采用搅拌摩擦焊接对1.2 mm厚的6016-T4铝合金和1.0 mm厚的镀锌IF钢进行搭接试验。通过对接头的力学性能和界面组织进行研究,发现在焊接速度为100 mm/min、旋转速度为800～2 000 r/min的条件下焊缝成形良好,表面无沟槽、孔洞等缺陷;当旋转速度为1 200 r/min时,接头的拉剪强度最高,达到172 MPa,为铝合金母材强度的82%;铝合金硬度值呈"W"型分布,最低值在接头两侧的热力影响区及其与热影响区的交界处,硬度最高值在接头的焊核区,达到69.1HV,镀锌IF钢硬度值呈倒"U"型分布,最高值在焊核区,达到192.3HV;在搅拌针和轴肩的共同作用下,铝和钢搭接接头的界面组织特征呈现机械连接+冶金连接的特点,在搅拌针作用区的两侧界面处各形成一个"钩子"状的结构,扎入铝合金基体中,形成机械连接,钢铝界面处生成的Fe-Al金属间化合物、Al-Zn化合物和Fe-Al的层状组织共同形成冶金连接。     

60mm厚度6061-T6铝合金板搅拌摩擦焊接接头微观组织与力学性能

采用搅拌摩擦焊接方法对6061-T6铝合金板进行了60mm双面对接焊实验,研究了搅拌摩擦焊接接头的微观组织与力学性能,结果表明:焊缝区微观组织沿厚度方向发生了不同程度的改变,焊接接头强度达到218MPa,为母材强度的70％;焊接热循环引发的金属强化相“重固溶”和“过时效”是接头力学性能下降的重要原因,其中前进侧热机影响...     

铝合金与镀锌钢薄板熔钎焊接头组织与力学性能

为了对铝合金和镀锌钢板进行优质高效焊接,采用Fronius冷金属过渡焊接机对锻铝6061和SPCC镀锌钢板进行了熔钎焊实验。焊接实验结果表明可以采用专家系统提供的参数进行焊接获得成型良好的接头;组织分析表明接头界面可以分为边缘富锌区、铝熔化区和铝钢界面反应层三个反应区。能谱分析结果表明边缘富锌区主要组成元素是锌和铝,铝钢之间的反应层主要是Fe2Al5反应相;接头上的缺陷主要有气孔、冷隔和低熔共晶缩孔。力学性能测试结果表明:铝、钢熔钎焊接头强度达到80MPa;Fe2Al5反应相平均硬度HV410,镀锌钢母材的平均显微硬度HV130,铝熔化区的平均显微硬度HV55。     

5083铝合金搅拌摩擦焊接头的显微组织与力学性能

对8 mm厚5083-H321铝合金板进行了搅拌摩擦焊接试验,研究了焊接工艺参数对搅拌摩擦焊接头显微组织和力学性能的影响。结果表明:该搅拌摩擦焊接头焊核区显微组织为细小的等轴晶组织,热机影响区为拉伸弯曲变形组织,热影响区非常窄,其晶粒尺寸与母材相当;综合接头表面形貌和拉伸性能得到较佳的搅拌摩擦焊接工艺参数为使用搅拌针为三棱形带螺纹、轴肩为内扣型的搅拌头,主轴转速为300 r·min^-1,焊接速率为120 mm·min^-1;在该工艺条件下接头表面成形良好,抗拉强度可达到母材的94.5%。     

铝/钢异种金属的超声振动强化搅拌摩擦焊接工艺

采用新型超声振动强化搅拌摩擦焊接工艺实现了6061-T6铝合金以及QP980高强钢的搭接焊,对比分析了有无超声作用下,接头的宏观形貌、微观组织和拉伸剪切性能,同时研究了超声振动对焊接载荷的影响。结果表明:焊接前对母材施加超声振动,可以起到软化母材的作用,促进了材料的塑性流动,扩大了铝/钢界面区和焊核区,使更多的钢颗粒随搅拌针旋转进入铝合金侧,在界面区边缘形成钩状结构,进而提高了接头的失效载荷;超声改变了FSW接头断裂位置和断口形貌,提高了接头力学性能,在本实验工艺参数范围内,接头最大的平均失效载荷为4.99 kN;当焊接速度为90 mm/min,下压量为0.1 mm时,施加超声振动使接头的平均失效载荷提高了0.98 kN,拉剪性能提升28.24%;施加超声振动后轴向力F_z、搅拌头扭矩M_t和主轴输出功率分别下降2.46%,6.44%和4.59%。     

Dissimilar friction stir welding between magnesium and aluminum alloys

Dissimilar friction stir welding between magnesium and aluminum alloy plates with thicknesses of 2 mm was performed. The tool for welding was rotated at speeds ranging from 800 to 1600 rpm under a constant traverse speed of 300 mm/min. For tool rotation speeds of 1000, 1200, and 1400 rpm, defect-free welds were successfully obtained and the surface morphology of the welds became smoother as the tool rotation speed was increased. The relatively simple bonded interface was clearly evident and had a zigzag pattern. A mixed microstructure of magnesium and aluminum alloys was formed near the bonded interface. The maximum tensile strength of about 132 MPa was obtained at the tool rotation speed of 1000 rpm. However, there were not noteworthy changes in the tensile strength as a function of the tool rotation speed. The elongation was 2% or less, regardless of the tool rotation speed.     

铝合金搅拌摩擦焊超声检测研究进展EI北大核心CSCD

铝合金搅拌摩擦焊(friction stir welding, FSW)焊接参数选择不当将会产生隧道孔、未焊透(lack of penetration, LOP)和吻接等取向复杂、细微紧贴的缺陷。首先,本文简述了FSW焊缝与典型缺陷特征,总结了超声检测时面临纵向分辨力低、缺陷表征不完整、材料与缺陷声阻抗接近和灵敏度不足等难点。随后,从常规超声、超声衍射时差法(time-of-flight diffraction, TOFD)、相控阵超声检测技术和其他超声检测技术等方面综述了现有的铝合金FSW超声检测研究工作。最后,结合超声信号处理方法和机器学习方法对研究前景进行展望:可以通过分析和提取信号特征,进一步提升超声检测分辨力和信噪比,并实现取向复杂缺陷和细微紧贴缺陷的精准辨识与定量。     

Dissimilar metals TIG welding-brazing of aluminum alloy to galvanized steel

Dissimilar metals TIG welding-brazing of aluminum alloy to galvanized steel was investigated, and the wettability and spreadability of aluminum filler metal on the steel surface were analyzed. The resultant joint was characterized in order to determine the brittle intermetallic compound (IMC) in the interfacial layer, and the mechanical property of the joint was tested. The results show that the zinc coated layer can improve the wettability and spreadability of liquid aluminum filler metal on the surface of the steel, and the wetting angle can reach less than 20°. The lap joint has a dual characteristic and can be divided into a welding part on the aluminum side and a brazing part on the steel side. The interfacial IMC layer in the steel side is about 9.0 μm in thickness, which transfers from (α-Al + FeAl₃) in the welded seam side to (Fe₂Al₅+ FeAl₂) and (FeAl₂+ FeAl) in the steel side. The crystal grain of the welded seam is obviously larger in size in the aluminum side. The local incomplete brazing is found at the root of the lap joint, which weakens the property of the joint. The fracture of the joint occurs at the root and the average tensile strength reaches 90 MPa.     

几何参数对2219铝合金拉拔式摩擦塞补焊接头微观组织及力学性能的影响EI北大核心CSCD

拉拔式摩擦塞补焊是火箭贮箱制造过程的重要技术之一。研究8 mm厚2219-T87铝合金拉拔式摩擦塞补焊接头的几何形状及其对接头微观组织和力学性能的影响。结果表明:塞孔及成形环几何形状对接头界面结合质量有重要影响。当焊接工艺参数为7000 r·min^(-1)主轴转速,35 kN轴向拉力以及16 mm轴向进给量时,使用锥直孔塞孔可有效防止塞棒在焊接过程中发生颈缩,从而消除接头未焊合缺陷;使用阶梯孔形成形环可以改善接头界面受力状态,防止弱结合缺陷产生。微观组织分析表明,毗邻结合界面的母材侧组织发生动态再结晶,热机械影响区组织发生明显塑性变形。接头附近组织受焊接热循环和塞棒旋转挤压作用发生明显软化,硬度最低值出现在热机械影响区,约为90HV。当接头存在焊接缺陷时,接头抗拉强度及伸长率较母材大幅降低,而无缺陷焊接接头的抗拉强度及伸长率分别为360.1 MPa和6.45%,接头系数为0.828,断裂方式为韧性断裂。     

Fatigue behavior of dissimilar friction stir welds between cast and wrought aluminum alloys

Cast aluminum alloy, AC4CH-T6, and wrought aluminum alloy, A6061-T6, were joined by means of friction stir welding (FSW) technique. The effect of microstructure and post heat treatment on fatigue behavior of the dissimilar joints was investigated. Near the weld centre, Vickers hardness was lower than in the parent metals and the hardness minima were observed along the trace route of FSW tool’s shoulder edge. Tensile fracture took place on A6061 side where the hardness was minimal, resulting in the lower static strength of the dissimilar joints than AC4CH or A6061. Fatigue fracture occurred on AC4CH side due to casting defects and the fatigue strength of the dissimilar joints was similar to that of AC4CH, but lower than that of A6061. Friction stir process (FSP) and post heat treatment successfully improved the fatigue strength of the dissimilar joints up to that of the parent metal, A6061. __________ Translated from Problemy Prochnosti, No. 1, pp. 150–154, January–February, 2008.     

Microstructure and enhanced atomic diffusion of friction stir welding aluminium/steel joints

Lap joints of friction stir welding between aluminium and stainless steel sheets were conducted using a welding tool with a cutting pin. The atomic diffusion of Fe–Al system during the severe plastic deformation was investigated. The interfacial microstructure and metallurgical reaction was analysed. The metallurgical reaction layers were identified as a compounds containing a phase of Al₃Fe, partial solid solution of Fe and Al, and amorphous with a thickness of 0.9–3.3?μm which depending on the process parameters. The interdiffusion coefficient between Al and Fe atoms is about 4 orders of magnitude compared with that under thermal equilibrium state. The nanocrystalline and partial amorphous were formed near the interface which may caused by the enhanced atomic diffusion.     

2060搅拌摩擦焊对接接头显微组织与析出相分析

本文选用Al-Li-Cu-Mg系铝锂合金2060,开展搅拌摩擦焊对接接头显微组织与析出相演变规律研究.搅拌摩擦焊对接接头,呈现典型的母材、热影响区、热机影响区和焊核区四区分布特点.母材为双向板条组织,在α板条中有大量三角形AlCu2Mn化合物析出,但在其它相区,当受到热影响时,该相消失;热影响区组织粗大,热机影响区晶粒受到机械力作用,前进侧拉长,后退侧破碎;焊核区为等轴晶组织,出现了高温析出相AlxCuxMn,均布于整个焊核区域.接头显微硬度在母材区最高,热影响区最低,焊核区低于母材,稳定在115 HV.     

Defects and tensile properties of 6013 aluminum alloy T-joints by friction stir welding

In this paper, 6013-T4 T-joints were successfully fabricated with different welding parameters by friction stir welding in two different combination modes of skins and stringers. The distribution features and formation mechanisms of defects in T-joints were observed and analyzed. The effect of defects and welding parameters on tensile properties of T-joints was investigated. The result shows that the T-joint without tunnel defect only can be obtained with the traverse speed of 100 mm/min in this experiment, and the welding parameters influence the features and sizes of kissing bond defects. The fracture of T-joints along the shin is attributed to the kissing bond defect and the tunnel defect is the main factor affecting the tensile properties along the stringer.     

基于热力耦合模型铝合金搅拌摩擦焊接顺序优化仿真分析

基于所建立的搅拌摩擦焊接过程热输入模型和热力耦合有限元分析模型,对带圆孔铝合金板的搅拌摩擦焊接顺序进行了有限元研究,并得到了焊接过程中不同焊接方案下的温度、瞬态应力变化曲线以及焊后残余变形。通过综合比较可以看出,从两边向中间焊的方案2优于从中间向两边焊的方案1和从左向右的顺序焊接的方案3。此外,有限元模型求解结果和实验测量数据具有相当好的吻合。