Analysis of Laser Micro Welding of Copper-Aluminum Dissimilar Metals and Its Mechanism

Micro welding of dissimilar metals can meet many performance requirements for modern engineering structures. In this experiment, laser micro welding of copper-aluminum dissimilar metals was conducted with an HWLW-300A energy negative feedback Nd:YAG pulse laser. By using the overlap welding method with copper on aluminum, with the laser energy being distributed unevenly, good weld joints were obtained. In this paper, the welding mechanism was analyzed from aspects such as welding temperature and the specific heat capacity of the solid metal. Existing defects were identified, and a feasible improvement scheme was proposed.

Microstructures and properties analysis of dissimilar metal joint in the friction stir welded copper to aluminum alloy

This paper mainly concentrated on the feasibility of friction stir welding of dissimilar metal of aluminum alloy to copper （I2） and a preliminary analysis of welding parameters influencing on the microstructures and properties of joint was carried out. The results indicated that the thickness of workpiece played an important role in the welding parameters which could succeed in the friction stir welding of dissimilar metal of copper to aluminum alloy, and the parameters were proved to be a narrow choice. The interfacial region between copper and aluminum in the dissimilar joint was not uniformly mixed, constituted with part of incomplete mixing zone, complete mixing zone, dispersion zone and the most region＇ s boundary was obvious. Meantime a kind banded structure with inhomogeneous width was formed. The intermetallic compounds generated during friction stir welding in the interfacial region were mainly CugAl4, Al2Cu etc, and their hardness was higher than oihers.

Effect of process parameters on microstructure and properties of laser welded joints of aluminum/steel with Ni/Cu interlayer

The effects of laser parameters and interlayer material on the microstructure and properties of the welded joint between 6061 aluminum alloy and stainless steel were studied.The results show that the density and microstructure of the welded joint can be optimized by changing the laser power with 0.05 mm Cu foil and 0.1 mm Ni foil as interlayer.A large number of new Cu-Al binary phases were found near the aluminum alloy,which effectively inhibited the formation of the binary brittle phase of Fe-Al.The maximum shear force of 1350.96 N was obtained with laser power of 2200 W.The shear force of the welded joint increased to 1754.73 N when the thickness of the Cu foil thickness changed to 0.02 mm.

Effect of the Welding Parameters on the Structural and Mechanical Properties of Aluminium and Copper Sheet Joints by Electromagnetic Pulse Welding

Aluminium-copper hybrid parts, as a substitution to copper parts, result in weight and cost reduction, and are relevant in applications related to the electronic, heating and cooling sector. However, aluminium to copper joined by thermal welding processes presents challenges in terms of achieving good joint quality. This is attributed to their dissimilar mechanical and thermal properties which result in large stress gradients during heating. This study investigated joining of aluminium to copper sheets by electromagnetic pulse welding, which is a solid-state process that uses electromagnetic forces for joining of dissimilar materials. Hybrid sheet welds were obtained for all parameters conditions, selected according to a Taguchi L18 design. The structural and mechanical characteristics were examined and related to the welding parameters by means of a Pareto analysis and response graphs. The welded zone started with a wavy interface with interfacial layers and defects and evolved to a flat interface without interfacial layers. The maximum transferable force depended on the minimum specimen thickness and the strength of the hybrid sheet weld. In case of aluminium sheet thickness reduction, the maximum transferable force was linearly correlated with the aluminium sheet thickness. High quality joints were obtained for no aluminium sheet thickness reduction and for a sheet weld strength which was at least as high as that of the base material. The most effective way to increase the transferable force was to lower the initial gap and to increase the free length, which resulted in no aluminium sheet thickness reduction. Alternatively, the use of a rounded spacer decreased the effect of the aluminium sheet thickness on the transferable force. An increase in weld width was achieved for an increase in capacitor charging energy and gap, whereas an increase in weld length was obtained for a decrease in gap. An increase in weld width did not necessarily result in an increase in the transferable force. In the regarded cases, a hybrid sheet with narrow weld width could therefore have higher quality.

基于Ni/Zn中间层的6061铝合金/Q355钢电阻点焊接头组织与性能

【目的】采用预置Ni/Zn中间层的方法进行Q355钢/6061铝合金异种金属的电阻点焊研究。【方法】在不同焊接时间、焊接电流及电极压力下分别对6061铝合金与Q355钢的电阻点焊工艺进行对比分析并获得最优电阻点焊工艺参数,然后采用在铝合金板与钢板之间添加Ni/Zn箔片作为中间层的方法来研究Ni/Zn中间层对铝/钢电阻点焊接头组织与性能的影响,并利用光学显微镜、扫描电镜、能谱分析及拉伸试验机等方法对含Ni/Zn中间层的铝/钢电阻点焊接头微观组织、元素占比、第二相的变化及抗拉剪力进行了研究。【结果】结果表明,铝/钢点焊接头由铝一侧熔核,钢一侧熔核和结合界面处的金属间化合物组成,具有典型的双熔核特征。通过在6061铝合金与Q355钢的中间分别增加Ni与Zn箔片来阻碍脆硬的Al-Fe金属间化合物的生成量。添加Ni中间层的接头界面区生成了韧性较好的Al3Ni,从而阻碍了硬而脆的Al-Fe金属间化合物的形成。添加Zn中间层的接头界面区生成了一定量的Fe2Al5Zn0.4,使Al-Fe金属间化合物层的厚度减小至2.88μm,最大抗拉剪力达到4.69 kN。【结论】添加Ni/Zn中间层后,铝/钢电阻点焊接头的熔核直径与抗拉剪力均有所提升,同时Ni元素的添加会在铝/钢界面处生成韧性较好的Al3Ni相,从而阻碍了Al-Fe金属间化合物的生成。

铝/铜异种金属搅拌摩擦焊接研究进展

铝/铜异种金属复合构件能够充分发挥铝和铜各自的优势,降低产品成本和重量,提高经济效益,为产品的设计和制造提供更多选择空间,因此在电力电子、新能源汽车等领域应用越来越广泛。然而,铝/铜两者之间热性能差异较大,两者实现高质量焊接面临着诸多困难。搅拌摩擦焊(Friction stir welding,FSW)作为一种固相焊接方法,具有热输入低、接头质量高的优点,已成为铝/铜异种金属的优选焊接方法之一。本文综述了近年来国内外学者在铝/铜异种金属FSW工艺、接头组织与性能调控FSW工艺改型等方面的研究进展,讨论了下一步应重点关注的问题,旨在理清铝/铜异种金属FSW工艺机理、技术难点和解决思路,为铝/铜异种金属FSW工艺优化与调控提供坚实的理论依据,以进一步推动FSW工艺在铝/铜异种金属复合构件成形中的广泛应用。

钛/钢异种金属连接技术研究现状

钛材有着多种优异的性能,在多个领域得到了广泛应用。但由于钛与钢之间物理化学性能的差异,两种金属焊接时会出现大量脆性间隙相,导致焊接接头失效。为解决因金属间隙相导致的接头失效,需尽量避免钛与钢的熔焊,采用合理的中间层是避免生成金属间隙相的有效途径,适当的连接方式及工艺是提高接头使用性能的有效手段。文章从压力焊、高能密度焊、钎焊、塞焊等几个角度对钛/钢异种金属连接的研究现状进行探讨,并展望了未来钛/钢异种金属连接的研究和发展方向。

铝/钢异种金属搅拌摩擦焊性能改善方法及其研究现状

铝合金与钢的复合结构具有质量轻、强度高、成本低等特点,广泛应用于航空航天、船舶重工、汽车制造等领域。搅拌摩擦焊(Friction stir welding,FSW)作为一种新型固相连接技术,具有高效、节能、环保等优势,但利用传统搅拌摩擦焊获得的铝/钢异种接头仍然存在诸多缺陷。基于铝/钢异种金属搅拌摩擦焊的优化,本文对目前已经在铝/钢搅拌摩擦焊方面取得成果的辅助方式进行总结归纳,将其划分为机械结构式辅助FSW、中间过渡层辅助FSW、温度控制型外源辅助FSW和超声振动辅助FSW,并在此基础上进一步展望了铝/钢异种金属搅拌摩擦焊优化方法的发展方向。

钛与钢异种材料焊接技术的研究进展

钛与钢两种材料在石油化工领域有着广泛的应用。由于它们在物理性能和化学性能方面存在显著差异,焊接时难以获得优异的焊接接头,因此针对钛与钢焊接过程中存在的问题进行分析,从钎焊、熔焊和压力焊三方面对其研究现状进行探讨,并对钛与钢异种材料焊接的发展前景进行展望。

Microstructure and Mechanical Properties of Hybrid Laser-Friction Stir Welding between AA6061-T6 Al Alloy and AZ31 Mg Alloy

For the purpose of improving the strength of this dissimilarjoint, the present study was carried out to investigate the improvement in intermetallic layer by using a third material foil between the laying edges of the friction stir welded and hybrid welded AI6061-T6/AZ31 alloy plates. The difference in microstructural and mechanical characteristics of friction stir welded and hybrid welded AI6061-TO/AZ31 joint was compared. Hybrid butt- welding of aluminum alloy plate to a magnesium alloy plate was successfully achieved with Ni foil as filler material, while defect-free laser-friction stir welding （FSW） hybrid welding was achieved by using a laser power of 2 kW. Transverse tensile strength of the joint reached about 66% of the Mg base metal tensile strength in the case of hybrid welding with Ni foil and showed higher value than that of the friction stir welded joint with and without the third material foil. This may be due to the presence of less brittle Ni-based intermetallic phases instead of Al12Mg17.

铝/铜异种金属搅拌摩擦焊接头腐蚀行为研究

采用搅拌摩擦焊接技术实现了3 mm厚6061-T6铝合金与T2紫铜的焊接,研究了Al/Cu搅拌摩擦焊接头的宏观成形、电化学腐蚀以及浸泡腐蚀行为。结果表明,Al/Cu搅拌摩擦焊接接头成形良好,未见裂纹、孔洞等缺陷。Cu的腐蚀电位高于Al,导致Al/Cu之间形成宏观电偶。Al/Cu接头的腐蚀电位低于两种母材,腐蚀电流密度大于两种母材,接头中的宏观电偶效应加速了接头的腐蚀。在浸泡24 h内,接头的腐蚀主要发生在铝合金侧,其中铝侧热影响区的腐蚀最严重,形成的点蚀坑尺寸较大。铝侧焊核区和铝母材也发生了局部点蚀,腐蚀程度相对较轻。铝侧表面腐蚀产物为Al(OH)3/Al2O3。

Laser-MIG Arc Hybrid Brazing-Fusion Welding of Al Alloy to Galvanized Steel with Different Filler Metals

Aluminum alloy plates were joined to galvanized steel sheets with lap joint by laser-MIG arc hybrid brazingfusion welding with AlSiS, AlSi12, AlMg5 filler wires, respectively. The influences of Si and Mg on the microstructure and mechanical properties of the brazed-fusion welded joint were studied. The increase of Si element in the fusion weld can make the grain refined, and increase the microhardness of the fusion weld. Therefore, the microhardness in fusion weld made from AlSi12 and AlSi5 filler wires can be up to 98.4 HV0.01 and 96.8 HV0.01, which is higher than that from AlMg5 filler wire of 70.4 HV0.01. The highest tensile strength can reach 178.9 MPa made with AlMg5 filler wire. The tensile strength is 172.43 MPa made with AlSi5 filler wire. However, the lowest tensile strength is 144 MPa made with AlSi12 filler wire. The average thicknesses of the intermetallic compounds （IMCs） layer with AlSiS, AlSi12, AlMg5 filler wires are 1.49-2.64 #m. The IMCs layer made from AlSi5, AlSi12 filler wires are identified as FeAl2, Fe2Als, Fe4Al13 and Al0.sFesSio.5, that from AlMg5 filler wire are identified as FeAl2, Fe2Al5 and Fe4Al13.

焊接速度对铝合金/铜激光熔钎焊接头组织及性能的影响

采用激光熔钎焊在不同焊接速度(4,5,6,7,8 mm·s^(-1))下对5052铝合金和T2铜进行对接焊,研究了焊接速度对接头宏观形貌、显微组织、显微硬度、抗拉强度及拉伸断裂机理的影响。结果表明:随着焊接速度增加,激光熔钎焊接头的焊缝成形先变优后变差,当焊接速度为6 mm·s^(-1)时焊缝成形最佳;随着焊接速度增加,接头中树枝状Al-Cu共晶组织变少,Zn-Al共晶组织变多,当焊接速度为6 mm·s^(-1)时接头铜侧界面反应区出现Al_(4)Cu_(9)和Al_(2)Cu金属间化合物,熔焊区由α-Al固溶体、η-Zn固溶体、Al-Cu共晶组织和Zn-Al共晶组织组成;随着焊接速度增加,铝合金/铜激光熔钎焊接头熔焊区硬度变化不大,铜侧界面反应区硬度下降,接头抗拉强度先增大后减小,拉伸断裂模式按照解理断裂、准解理断裂、韧性断裂、准解理断裂顺序依次变化,当焊接速度为6 mm·s^(-1)时抗拉强度(212 MPa)最大,接头发生韧性断裂。

铜-镍中间层对钛/钢激光焊接头组织与性能的影响

文章采用添加铜-镍作为中间层的激光热导焊工艺制备钛/钢搭接焊接头,通过改变激光功率对焊接接头组织与性能的变化进行研究。研究表明,铜-镍中间层的加入改变了钛/钢激光焊接熔池的组织形貌以及元素分布情况,通过SEM、EDS、XRD等对熔池各区域检测分析,发现在靠近钛母材一侧形成了Ti-Ni、Ti-Cu等新相,有效抑制了Fe-Ti二元脆性相的产生,通过力学实验发现激光功率为2900W时,钛/钢焊接接头的力学性能最好,最大剪切力为1845.02N,说明铜-镍中间层的添加改善了钛/钢异种金属的焊接性。

纳米颗粒增强的铝铜异种金属等离子弧熔钎焊接头性能优化研究

铝铜异种金属连接技术因工程应用的需求而备受关注,但传统焊接方法难以满足日益增长的性能要求。纳米颗粒增强技术为优化铝铜异种金属焊接接头性能提供了新的可能。研究通过向铝铜异种金属等离子弧熔钎焊接头中添加不同种类和浓度的纳米颗粒,深入分析其对接头力学性能、微观组织和耐腐蚀性的影响。实验结果表明,适量和适当种类的纳米颗粒可以显著提高接头的力学性能、微观组织稳定性和耐腐蚀性,为铝铜异种金属等离子弧熔钎焊接头的性能优化提供了有效解决方案。

不锈钢与钛合金电子束熔覆增材焊接工艺分析

不锈钢与钛合金的双金属结构已在化工、航天、航空等领域得到了广泛的应用。基于对异种金属构件焊接技术的研究,分析了异种金属焊接在熔点、膨胀系数、热导率、比热容等方面的性能特点。基于电子束异种金属的焊接工艺及特点,进一步讨论了不锈钢-钛合金电子束熔覆增材焊接技术。采用电子束熔覆增材焊接技术对不锈钢和钛合金进行焊接时,需要考虑过渡层的设置、焊接的强度与耐腐蚀性工艺、气体环境保护等重要的环节。

铝与钢异种金属焊接的研究与发展概况

分析了铝与钢的焊接性,综述了国内外铝与钢异种金属焊接的研究与发展状况,重点介绍了目前应用于铝与钢连接的焊接方法,并对各种焊接方法的优缺点作了分析比较。

基于旁路耦合电弧的铝钢MIG熔钎焊研究

实现铝钢良好连接的关键是有效控制焊接热输入,尽量降低中间层铝铁金属间化合物的厚度,一般认为中间层金属间化合物厚度小于10μm时铝钢接头质量良好。提出旁路耦合电弧熔钎焊方法,通过调节旁路电弧电流的大小来控制焊接热输入。在优化控制系统和工艺参数的基础上采用脉冲旁路耦合电弧焊方法将铝镁合金ER5356堆焊到304不锈钢板上,获得结合良好的焊缝。对焊接接头进行扫描电镜(Scanning electron microscope,SEM)、能量色散光谱仪(Energy dispersive spectrometry,EDS)分析,结果表明:铝与不锈钢焊接接头中间层金属间化合物平均厚度约为8μm,小于10μm的临界厚度;脉冲旁路耦合电弧焊方法能够实现铝钢的连接,是一种新型低成本低热输入电弧焊方法。

钢/铝异种金属双熔池TIG熔钎焊接头的显微组织与力学性能

采用电弧加热镀锌钢板,通过热传导使铝合金熔化,形成两个互不接触的熔池,实现钢/铝异种金属搭接熔钎焊;利用扫描电镜(SEM)与能谱(EDS)对连接界面的微观组织进行观察与分析。结果表明:在连接界面形成两种金属间化合物,一种为接近铝合金母材呈针状或絮状的FeAl3,另一种为接近钢呈舌状或条状的Fe2Al5;反应层FeAl3的厚度在连接界面上的分布大致均匀;而反应层Fe2Al5的厚度从焊缝中心向两侧逐渐变薄;随着焊接线能量的升高,接头的承载能力呈先增大而后减小的趋势,最高承载能力可达177.2 N/mm,为铝合金母材强度的84%。

几种铝钢异种金属熔钎焊工艺的对比与分析

采用脉冲旁路耦合电弧MIG焊、CMT及激光焊方法实现铝/镀锌钢板搭接焊,对焊缝界面微观组织、形貌及元素成分进行了观察分析,并测试了其力学性能.结果表明,三种焊接方法均可以实现铝/镀锌钢板异种金属的优质连接,获得成形良好的焊缝,搭接接头的抗拉剪强度均可以达到铝合金母材的80%以上,拉伸试样断裂在焊缝铝合金母材热影响区.当母材热输入及工艺合适时,三种方法下搭接接头界面处均形成一主要成分为Fe2Al5和FeAl3,平均厚度约为8μm的金属间化合物,而且控制金属间化合物的生成是获得铝/钢焊接优质接头的关键.