Microstructure characteristics and corrosion behavior of metal inert gas welded dissimilar joints of 6005A modified by Sc and 5083 alloys

The corrosion behavior and microstructure characteristics of metal inert gas(MIG)welded dissimilar joints of the 6005A alloy modified with Sc(designated as 6005A+Sc)and the 5083 alloy were investigated using corrosion tests and microscopy techniques.Results show that the dissimilar joints exhibit strong stress corrosion cracking(SCC)resistance,maintaining substantial strength during slow strain rate tensile tests.Notably,the heat-affected zone(HAZ)and base metal(BM)on the 6005A+Sc side show superior performance in terms of inter-granular corrosion(IGC)and exfoliation corrosion(EXCO)compared to the corresponding zones on the 5083 side.The lower corrosion resistance of the 5083-BM and the 5083-HAZ can be attributed to the presence of numerous Al_(2)Mg_(3)phases and micro-scaled Al_(6)(Mn,Fe)intermetallics,mainly distributed along the rolling direction.Conversely,the enhanced corrosion resistance of the 6005A+Sc-BM and the 6005A+Sc-HAZ can be attributed to the discontinuously distributed grain boundary precipitates(β-Mg_(2)Si),the smaller grain size,and the reduced corrosive current density.

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.

Microstructure and mechanical properties of dissimilar Al-Cu joints by friction stir welding

Dissimilar friction stir welding between 1060 aluminum alloy and annealed pure copper sheet with a thickness of 3 mm was investigated. Sound weld was obtained at a rotational speed of 1050 r/min and a welding speed of 30 mm/min. Intercalation structure formed at the crown and Cu/weld nugget （WN） area promotes interracial diffusion and metallurgical bonding of aluminum and copper. However, corrosion morphology reveals the weak bonding mechanism of internal interface, which causes the joint failing across the interface with a brittle-ductile mixed fracture mode. The tensile strength of the joint is 148 MPa, which is higher than that of the aluminum matrix. Crystal defects and grain refinement by severely plastic deformation during friction stir welding facilitate short circuit diffusion and thus accelerate the formation of A14Cu9 and A12Cu intermetallic compounds （IMCs）. XRD results show that A14Cu9 is mainly in Cu/WN transition zone. The high dislocation density and formation of dislocation loops are the major reasons of hardness increase in the WN.

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.

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.

Friction plug−riveting spot welding of AA 7075-T6 aluminum alloy and low carbon steel using 1045 steel rivet

7075-T6 aluminum alloy/low carbon steel joint was carried out via a novel friction plug−riveting spot welding process.This process utilized uniquely designed steel rivets with a tip and groove shape.The macro-morphology formation,microstructure,microhardness and lap shear performance of joints were investigated.As the spindle down distance increased,the rivet tip was friction welded with the lower steel sheet,resulting in the formation of a solid phase welding zone exhibiting metallurgical bonding.Additionally,a hook was formed in the joint,providing the mechanical locking.The results showed that under optimal parameters of spindle down distance of 3.4 mm,rotation speed of 4000 r/min,and spindle down speed of 2.4 mm/s,the lap shear load of the joints reached a maximum of 14.36 kN.Failure occurred at the aluminum alloy base metal.

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.

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.

Cu对铝/钢CMT熔钎焊接头界面区组织的影响研究

采用冷金属过渡方法,以AlSi5焊丝为填充金属,在5052铝合金和镀锌钢板之间添加铜箔片进行搭接熔钎焊,使用扫描电子显微镜结合能谱分析和拉伸试验机对接头的界面区组织与性能进行研究。结果表明,未加入铜箔时,界面区组织主要由FeAl_(3)金属间化合物组成;铜箔的加入使得界面区组织中新生成了CuAl_(2)金属间化合物,同时改善了Zn在界面区的分布。Zn固溶于Al中,一定程度上抑制了Fe-Al金属间化合物产生。加入铜箔后的试样断裂位置发生改变,接头的承载能力与未加入铜箔的相近。

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。

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。

1050A纯铝/TA15钛合金异种金属冷焊接头组织与性能

【目的】该文旨在研究1050A纯铝/TA15钛合金异种金属冷焊接头的组织与性能。【方法】采用JH-2000冷焊机对1050A纯铝/TA15钛合金异种金属进行了对接焊试验,通过优化焊接工艺参数实现了冷焊技术对铝/钛异种金属的连接。由于冷焊具有高频放电、瞬间高温的特点,焊接热输入低,接头界面金属间化合物层厚度较小,冷焊能得到成形质量良好、内部近无缺陷的优质接头。【结果】结果表明,在脉冲时间30 ms、脉冲电流30 A的焊接工艺参数下,接头界面金属间化合物最少,接头平均抗拉强度达到120.3 MPa,抗拉强度超过纯铝母材的88%。断裂类型为韧性-脆性混合断裂,接头界面铝侧焊缝区为异种接头的力学性能的薄弱区。【结论】显微组织热量输入对钛/铝异种接头界面显微组织金属间化合物层的成形和数量具有较大影响。金属间化合物的数量对铝/钛异种金属焊接接头的力学性能显著影响。

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。

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。

铜中间层对不锈钢-铝合金激光搭接焊质量的影响

探讨了不同厚度铜中间层对301L不锈钢和6082-T6铝合金激光焊接接头组织和力学性能的影响。试验采用10 kW光纤激光器,机器人自动化焊接,并设定了不同的焊接功率和速度。结果表明,添加铜中间层后,在焊接速度为31 mm/s、激光功率3.1~3.5 kW时均能获得外观质量良好的焊缝;随着焊接热输入量的增加,焊缝形貌由V形向钉子形转变,而当铜中间层厚度为0.1 mm时,焊缝出现明显的缩颈;添加铜中间层后,焊缝边缘硬度降低,韧性和力学性能提高,裂纹减少;拉剪强度随焊接参数增加先升后降,当铜中间层厚度为0.05 mm、激光功率3.1 kW、焊接速度31 mm/s时,焊缝拉剪强度最高;不同厚度铜中间层的最佳焊接参数不同;铜中间层能有效改善不锈钢和铝合金激光焊缝的质量,提高接头力学性能,但需选择适宜的铜中间层厚度和焊接参数。

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。

铜与不锈钢焊接技术与工艺研究现状

铜与不锈钢的合金结构件广泛应用于石油化学、空调冷凝、航空航天和汽车零部件等中高端工业领域,存在着广阔地展现出极高的实用价值和应用潜力。由于铜与不锈钢物理化学性质差异较大,使得两者之间的焊接相当困难,文章通过分析铜与不锈钢的焊接性,综述了各种焊接方法及其原理,分析了各种焊接缺陷以及解决办法,并指出当前领域内的研究热点与难点。同时,文章还将展望铜与不锈钢异种金属焊接技术的未来发展趋势,以期推动该领域的持续进步。

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。