Mg/Al异种金属焊接的研究现状

Mg/Al异种金属焊接的主要问题在于母材本身极易氧化,热传导系数大,易产生热裂纹和气孔等缺陷,尤其是极易形成金属间化合物,都严重影响了焊接接头的性能。本文在对常规熔焊如TIG焊、电子束焊、激光焊等方法进行了总结的基础上,归纳了抑制金属间化合物产生的方法,包括加入第三种元素、采用复合热源以及固相焊如扩散焊、搅拌摩擦焊等。从控制金属间化合物的角度来看,固相焊的研究仍将是Mg/Al异种金属连接的主要发展方向。     

异种金属和镀层金属的焊接

镁铝异种材料T1G焊接接头扩散行为分析；镁-铝异种金属激光-T1G复合热源焊焊接性分析；16MnR低合金钢与BFe30-1-1异种材料的焊接；待焊表面组织对异种钢超塑性焊接的影响。     

激光-TIG复合热源焊接参数对镁/钢异种材料焊接接头的影响

采用激光-TIG复合热源的焊接方法对镁和钢异种材料进行焊接,探讨了焊接工艺参数包括激光功率、激光离焦量、焊接速度以及TIG焊接电流对焊缝抗拉强度的影响.结果表明,在焊接过程中,随着激光功率的增大、焊接速度的减小,焊缝抗拉强度随之增大;随着激光离焦量的增加,焊缝抗拉强度呈现先增大后减小的特点;而TIG电流的变化对焊缝抗拉强度影响不大.试验证明,在合适的工艺参数下,能够得到成形良好、力学性能优良的镁/钢异种材料的焊接接头,并且在焊接过程中,激光对镁和钢的连接起主要作用.     

镁-铝异种金属冷金属过渡连接焊接性分析

通过CMT(Cold Metal Transfer)冷金属过渡焊接的工艺对镁(AZ31B)-铝(6061)异种金属焊接性进行了研究,试验中选用AZ61,4043焊丝、采用热镀锌钢板HDG60作为过渡金属,分别用于镁-钢、铝-钢侧焊接,选取合适的焊接工艺参数,使其间接实现了镁-铝异种金属连接的目的。研究得出:使用这种方法可以形成镁-钢熔钎焊焊接接头,铝-钢熔钎焊焊接接头组成的复合接头;同时冷金属过渡焊接可以通过保持较低焊接热输入从而降低界面反应层的厚度;而且镀锌钢板中间过渡层的使用也避免了镁-铝直接焊接时形成的脆性金属间化合物,如Al_3Mg_2,Mg_(17)Al_(12)等。采用该方法连接的镁-铝异种金属焊接接头的抗拉强度超过180 MPa,并且有较好的断后伸长率,相比铝镁异种金属CMT直接焊接,性能得到很大的改善,因此使用镀锌钢板中间过渡层的使用实现铝镁异种金属之间的连接是一种行之有效的方法。     

其它焊接方法

5A02／Q235钢Nd：YAG激光·脉冲MIG复合热源熔-钎连接；激光-TIG复合热源焊接参数对镁／钢异种材料焊接接头的影响；激光-电弧复合焊接咬边缺陷分析及抑制方法； 激光＋GMAW复合热源焊焊缝成形的数值模拟——Ⅱ．组合式体积热源的作用模型     

镁铝异种金属焊接研究现状与进展

综述了近年来国内外镁铝异种金属焊接的可行性和焊接方法的研究现状,对镁铝焊接的方法、特点、应用及组织演化特征进行了分析,认为镁铝异种材料焊接时,有效控制接头金属间化合物的组成、大小、形貌及分布状态是获得优质焊接接头的关键。对未来镁铝焊接的研究趋势进行了预测,认为镁铝的熔化焊接是一种高效且实用的焊接方法,具有广泛的应用前景,该方法的连接机理及失效分析还要需进一步研究和探讨。     

其它焊接方法

5A02／Q235钢Nd：YAG激光·脉冲MIG复合热源熔-钎连接；激光-TIG复合热源焊接参数对镁／钢异种材料焊接接头的影响；激光-电弧复合焊接咬边缺陷分析及抑制方法； 激光＋GMAW复合热源焊焊缝成形的数值模拟——Ⅱ．组合式体积热源的作用模型     

钛/铝异种合金激光焊接研究

钛、铝异种金属物化性能差异较大,焊接过程中易生成脆性金属间化合物,弱化接头性能,激光热输入量的控制是钛/铝异种合金焊接的关键。采用1 000 W光纤激光器对1 mm厚的LD2铝板和TC4钛板进行对接焊试验。试验重点研究焊接速度和激光偏置距离对热输入量的控制和分配,通过金相显微镜、SEM、EDS方法对焊缝微观组织和结构进行分析,利用拉伸试验机进行力学性能测试。研究结果表明,当激光作用在钛侧0.24 mm处,焊接速度为80 mm/s时,形成的金属间化合物仅2μm左右,获得了质量良好的焊接接头,断后伸长率为5.42%,抗拉强度可达242 MPa。     

镁合金-钢异种材料熔化焊研究现状

镁合金-钢异种金属复合结构具有巨大的使用价值,特别是在船舶、汽车、航空航天等领域.由于镁与钢熔沸点差异巨大,Mg在Fe中不固溶,无法形成固溶体和金属间化合物等,因此,镁合金-钢异种金属熔化焊还存在较多问题.本文从镁合金-钢的焊接性与实现焊接的总体要求这两个角度出发,对镁合金-钢异种金属熔化焊的研究现状进行了讨论.重点分析了电弧、激光、电弧-激光复合焊在焊接镁合金与钢时的优点与不足,并针对不足提出了工艺改进方法.从目前镁合金-钢异种金属焊接中存在的问题和未来发展的趋势出发,总结出了今后镁合金-钢熔化焊的重点内容.     

钢/铝异种金属连接工艺的研究现状

近年来采用钢与铝异种金属连接结构的产品越来越多,采用钢铝异种金属焊接可以减轻结构部件的重量,实现轻量化。但钢铝焊接时易出现裂纹、金属间化合物等,严重影响了焊接接头质量。笔者阐述了近年来国内外钢铝异种金属之间各种焊接工艺（压焊、钎焊、熔焊、搅拌摩擦焊）的研究现状,认为激光熔-钎焊方法既易于控制焊接热输入,又能较好的控制钢铝金属间脆性物质层,是一种实现钢与铝异种金属连接的具有前景的工艺。     

Improvement of TIG lap weldability of dissimilar metals of Al and Mg

Abstract

The technique of tinning on magnesium has been used to improve the tungsten inert gas (TIG) lap weldability of dissimilar alloys of dissimilar metal Al 6061 to Mg AZ31B. The composition at the interface of the samples welded both directly and after tinning on magnesium was mapped by electron probe microstructure analysis (EPMA). Results revealed that tinning on the magnesium plate could eliminate the factors which affect the wet ability at the interface of the samples TIG welded directly. Tinning did not prevent the interaction between Mg and Al to form intermetallic compounds completely, but reduced the intermetallic compounds to some degree.     

镁/铝异种金属焊接的研究现状与展望

镁合金和铝合金（Mg合金和Al合金）都具有很多优良的特性,在现代工业中占有越来越重要的地位,实现Mg/Al异种金属的可靠焊接对于轻量化的发展具有重要意义。然而,在Mg/Al异种金属焊接过程中存在一些亟待解决的问题,例如Mg合金和Al合金易氧化、易形成气孔和连续分布的金属间化合物（IMCs）等严重影响接头性能。本文分析了Mg/Al异种金属的焊接性,回顾了Mg/Al异种金属焊接技术的研究进展,阐述了Mg-Al IMCs的改善和消除,并对Mg/Al异种金属焊接提出了展望。     

Novel hybrid method： pulse CO2 laser-TIG hybrid welding by coordinated control

0IntroductionRecently,laser-arc hybrid welding,as a rising spe-cial manufacture technology,has attracted more and moreinterest and attentions of some researchers and weldingcompanies.But,concerning laser-TIG hybrid welding,most of the research in this area mainly focused on contin-uous wave laser-TIG arc hybrid welding[1-3].In previousworks,because of the absorption and defocusing of laserenergy by hybrid arc plasma,the energy loss of laser wasvery serious when laser traversed arc in continu…     

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.     

Effect of relative location of laser beam and TIG arc in different hybrid welding modes

Abstract

The laser leading hybrid welding mode [laser tungsten inert gas (laser-TIG)] and TIG leading hybrid welding mode (TIG-laser) were utilised in the magnesium alloy welding process. The effects of TIG arc current and the distance between laser beam and TIG electrode (Dla) on penetration depth and melting efficiency in different hybrid welding modes were investigated. Results reveal that there is a decided difference in variation trend of penetration depth with Dla in different welding modes. The penetration depth increases first and then decreases with the Dla increasing from 1 to 7 mm in TIG-laser hybrid welding mode while the penetration depth decreases monotonously with Dla in laser-TIG hybrid welding mode. The increase percentage of melting efficiency remains at ～20% in laser-TIG hybrid welding mode while the increase percentage fluctuates acutely and achieves the maximal value (～53·14%) at the arc current of 120 A in TIG-laser hybrid welding mode.     

Laser-TIG hybrid welding of ultra-fine grained steel

For improving the weldability of ultra-fine grained (UFG) steel, detailed experiments of laser-tungsten inert gas (TIG) hybrid welding were carried out on this material to investigate the effects of welding parameters on weld shape, microstructure, grain growth in heat-affected zone (HAZ) and mechanical performance. For the hybrid welds, increasing energy ratio of laser to arc (ER_LA) can narrow weld width, reduce the tendency of grain growth and ferrite grain coarsening in HAZ and also make the microstructure of fusion zone gradually change from coarse pearlite to fine martensite and bainite. The hybrid weld with low ER_LA has obvious softening zone in HAZ; while that with high ER_LA has no softening zone because of the low line energy. Compared to laser weld, under appropriate welding parameters hybrid weld with high ER_LA can obtain higher welding speed, better weld shape and more sound mechanical performance including similar tensile strength and higher toughness. These results demonstrated that laser-TIG hybrid welding is an effective process for UFG steel.     

电场提高激光-TIG复合焊熔深的机制

通过对比电场对单激光和单TIG焊接电弧在镁合金板材上堆焊熔深的影响,分析了外加电场对激光-TIG复合焊熔深的影响机制.同时通过研究在不同激光功率、不同TIG电流强度下电场的作用效果,对该机制进行了验证.结果表明,外加电场对激光-TIG复合焊熔深的作用是通过对激光小孔内等离子中带电粒子运动的控制来实现的.外加电场使小孔内电子向小孔底部运动时,可以增加焊接熔深;激光功率越大,外加电场增加熔深效果越明显;增大TIG焊接电流,削弱外加电场对熔深的增加作用.     

激光-TIG复合热源焊接钛合金T形结构焊缝成形特点及影响因素分析

采用激光-TIG弧复合焊接工艺对钛合金T形结构单面焊背面双侧一次成形焊接新技术进行了研究,通过综合试验、对比分析等方法,研究了多种试验条件下T形结构焊缝成形特点及影响因素,给出了采用激光-TIG复合焊接工艺实现钛合金T形结构单面焊背面双侧一次成形焊接的最佳工艺方案.结果表明,采用激光-TIG复合焊接工艺焊接钛合金T形结构与钨极氩弧熔透焊工艺相比在焊缝组织、焊接效率、焊缝成形、间隙适应性等方面有明显的优势.     

钛合金激光-TIG复合焊接保护状态对焊缝成形及性能影响

用激光-TIG复合热源对2.5 mm厚TA15钛合金进行对接焊试验.利用万能力学拉伸机、红外热成像仪、电子探针（EPMA）、扫描电镜（SEM）等分析手段对焊接接头进行测试分析，并与单TIG焊进行对比.分析焊接工艺参数和接头保护时间对焊接接头形貌和性能的影响.结果表明，实现2.5 mm厚钛合金全熔透焊接时，激光-TIG复合焊比单TIG焊速度更快、热输入更低，焊缝和热影响区更窄，晶粒更细；相同保护条件下，激光-TIG复合焊接头比单TIG焊接头具有更高的强度、塑性和更好的疲劳性能；激光-TIG复合焊缝冷却速率高于单TIG焊，获得良好的保护状态时所需保护时间更短.     

Joining Dissimilar Mg/Al Alloys by Solid-State Friction Spot Welding

JOM - To reduce intermetallic compounds (IMCs), dissimilar Mg/Al alloys were joined by solid-state friction spot welding. No incomplete refilling was observed when Al sheet served as the upper...