共查询到20条相似文献,搜索用时 250 毫秒
1.
镁合金和铝合金由于其轻质高强的特性在航空航天领域中被广泛应用,然而铝/镁异种合金的焊接却是一个极具挑战性的任务,因为铝/镁物理化学性质存在显著差异,易形成的脆性Al–Mg金属间化合物严重影响接头强度。本文从焊接方法角度讨论了目前铝/镁异种合金焊接研究现状,包括激光焊、TIG焊、搅拌摩擦焊、超声波焊、磁脉冲焊和一些其他的焊接方法;归纳了国内外为提高铝/镁异种合金焊接的综合力学性能做出的各种努力,具体包括采用固态焊接、加中间层、优化焊接工艺参数和复合焊接等来抑制镁铝金属间化合物的生成与长大。最后对铝/镁焊接的研究趋势进行了总结和展望。 相似文献
2.
异种材料构件因其可实现不同材料的优异性能组合,极大提高设计和生产的灵活性,满足现代工程结构的功能和性能要求,具有更高的技术和经济价值,在各领域有广阔的应用前景。因此,异种材料的可靠连接尤为重要。然而,异种材料往往因物理及化学性能差异较大导致连接困难。本文综述了异种材料钎焊、激光焊、电子束焊、电弧焊以及搅拌摩擦焊的国内外研究进展和应用现状,总结了各焊接方法在异种材料连接过程中的研究焦点。在此基础之上,对异种材料连接进行了总结和展望,拟为未来异种材料连接的研究方向和技术突破提供参考。 相似文献
3.
4.
5.
采用无针搅拌摩擦搭接点焊对Ti6Al4V钛合金和2A12铝合金异种金属进行焊接,焊后低熔点铝合金受摩擦热影响发生熔化,而高熔点钛合金在焊接过程中始终保持固态,同时与处于液态的铝合金相互作用,最终Ti/Al界面形成熔钎焊接头且接头拉伸剪切力达19.20 kN。研究了Ti/Al熔钎焊接头钛合金和铝合金的组织变化以及连接界面的特征形貌。结果表明由于摩擦热及搅拌头下压的影响,焊点处钛合金和铝合金组织发生明显变化。钛侧主要形成热力影响区和母材区;铝侧形成熔核区、热影响区和母材区3个区域,热影响区和熔核区的晶粒尺寸相对母材区变粗大,其组织经历了受热长大、部分熔化到完全熔化3个过程。在搭接接头界面处形成均匀致密且微薄的金属间化合物层,主要成分为TiAl3;接头界面区组织变化明显,中间部位有均匀的TiAl3界面层,随着向接头两边延伸界面层逐渐消失且Cu元素聚集在边缘。相对其他Ti/Al搭接点焊的焊接方法,无针搅拌摩擦搭接点焊获得的接头抗拉伸剪切力得到了明显的提升。 相似文献
6.
通过搅拌摩擦焊实现了5 mm纯钛的可靠连接,并对焊接接头组织进行了细致研究。通过光学、扫描电子显微镜和透射电子显微镜对纯钛搅拌摩擦焊组织进行了精细表征,对焊接过程中的再结晶机制进行了研究。结果表明:采用搅拌摩擦焊可以得到成型良好,组织致密的焊缝;焊缝组织可以分为焊核区( NZ)、热机影响区( TMAZ)、热影响区( HAZ)和母材区( BM);根据各区组织形态和结构特点对纯钛搅拌摩擦焊动态再结晶过程进行了分析,揭示了纯钛搅拌摩擦焊焊缝细化机制;钛的层错能较大,搅拌摩擦产生的位错不能完全分解,遇到阻碍时,只能通过滑移和攀移继续运动,在多次搅拌摩擦作用下,位错缠结堆积,位错密度不断上升,产生新的晶界,从而形成细小晶粒,实现晶粒细化。 相似文献
7.
轻型快速舰船的搅拌摩擦焊 总被引:1,自引:0,他引:1
船舶市场的快速发展要求船舶制造业以比以往更低的成本和更快的交货期来满足市场需要 ,英国焊接研究所 (TWI)发明的搅拌摩擦焊技术为新世纪大型船舶壁板和成型件的批量工业化制造提供了有效途径。搅拌摩擦焊对于轻合金材料 (如铝、铜、镁、锌等 )的连接在焊接方法、机械性能和生产效率上具有其他焊接方法不可比拟的优越性。搅拌摩擦焊是一种固相连接方法 ,焊缝接头具有优良的机械性能和小的焊接变形 ,焊接过程中 ,不需要添加保护气和添丝 ,没有熔化、烟尘、飞溅、弧光 ,是一种环保型的新型连接技术。基于搅拌摩擦焊在焊接方法、机械性能… 相似文献
8.
随着结构轻量化概念的逐渐普及和发展,聚合物及其纤维增强材料在航空结构逐步得到了应用。聚合物及其纤维增强材料具有密度小、比强度高、耐腐蚀、耐热性好等优异性能,采用金属/聚合物复合结构既可以提高结构整体使用性能,又可以减轻重量、节约成本、实现轻量化的目标。从金属/聚合物连接的背景意义出发,对胶接、机械连接、激光焊等几种在金属/聚合物结构的连接中应用范围较广且工艺较为成熟的方法的优劣势进行了分析,并重点介绍了金属/聚合物基于摩擦连接技术研究现状,主要包括搅拌摩擦缝焊、搅拌摩擦点焊、摩擦铆接、摩擦注射铆接以及摩擦自铆接5种连接方法在金属/聚合物结构连接中的应用情况。最后,对金属/聚合物连接技术所涉及的连接机理及未来的研究方向进行了总结与展望。 相似文献
9.
吴会强%冯吉才%何鹏%石常亮 《宇航材料工艺》2004,34(5):10-14
综述了钛铝基金属间化合物(主要是Ti3Al,TiAl)熔焊连接技术的研究现状,主要涉及电子束焊、激光焊和氩弧焊等方法,指出钛铝基金属间化合物的焊接性不存在本质上不可焊的问题。无论采用何种熔焊方法连接此类合金,焊态下焊接接头的组织和性能一般不理想,焊缝和热影响区很容易脆化。控制冷速是成功连接此类材料的关键,同时受该类材料的物理冶金学特点限制,其组织转变动力机制、氢脆、间隙元素的引入对其焊接性的影响尚未引起注意。 相似文献
10.
11.
《中国航空学报》2021,34(4):375-386
Laser welding of dissimilar titanium/aluminum alloys has been employed at an increasing rate, particularly in the aerospace industry, owing to its advantages in terms of current design flexibility and fuel/cost savings. The major problem with dissimilar Ti/Al welds arises from the difference in the thermal expansion and contraction of the two metals, which leads to hot-cracking susceptibility and the mitigation of the mechanical property after welding. In the present study, pulsed Nd:YAG laser welding of Ti6Al4V and AA6060 has been addressed. Hot-cracking susceptibility in the heat affected zone and the shear fracture behavior of the lap joints were investigated through microstructural characterization and mechanical tests. The results indicate that the hot cracking tendency can be reduced by increasing the pulse peak power (7.5–8.5 kW) and the laser point diameter (0.8–1.0 mm) with specific pulse duration and overlap. An alternative control strategy for less hot cracks in the Ti/Al lap joint can be to increase the weld width and decrease the cooling rate during solidification. The shear fracture of the Ti/Al lap joint is likely to occur along the lower side path of the weld interface with decreasing weld surface collapsed amount and increasing aluminum base metal melt depth. 相似文献
12.
《中国航空学报》2020,33(3):792-804
SiCp/Al composites have excellent comprehensive properties and have been widely used in aerospace, automotive industry and other fields. Due to the huge difference in performance between SiC particles and matrix alloys, traditional fusion welding methods are difficult to meet the join requirements of SiCp/Al composites. Friction stir joining (friction stir welding), as a solid phase joining process, has been proved to be a new technology with fine prospect in joining SiCp/Al composites compared with fusion welding process. Although some progress has been made in recent years, there are still full of challenges. In this paper, the research status of friction stir joining of SiCp/Al composites in recent years is expatiated, including the weldability of SiCp/Al composites, the macrostructure and the microstructure of joints, mechanical properties of joints, and tool wear and monitoring. Furthermore, the existing challenges of friction stir joining of SiCp/Al composites are summarized and the future development directions are prospected. 相似文献
13.
焊接接头力学性能不均匀性的研究 总被引:2,自引:0,他引:2
研究1Cr18Ni9Ti材料氩弧对接焊接头的力学性能不均匀性,用金相分析和微形剪切试验得到焊接接头上不同组织区的力学性能分布特性。结果表明,在熔合区组织不均匀性与力学性能不均匀性最为严重,是焊接接头最薄弱的环节。焊接接头的疲劳试验表明,初始裂纹一般发生在熔合区,同时焊接接头力学性能不均匀性会导致焊接接头疲劳寿命降低40%~60% 相似文献
14.
《中国航空学报》2023,36(8):454-471
A novel friction stir double-riveting welding (FSDRW) technology was proposed in order to realize the high-quality joining of upper aluminum (Al) and lower copper (Cu) plates, and this technology employed a Cu column as a rivet and a specially designed welding tool with a large concave-angle shoulder. The formations, interfacial characteristics, mechanical properties and fracture features of Al/Cu FSDRW joints under different rotational velocities and dwell times were investigated. The results showed that the well-formed FSDRW joint was successfully obtained. The cylindrical Cu column was transformed into a double riveting heads structure with a Cu anchor at the top and an Al anchor at the bottom, thereby providing an excellent mechanical interlocking. The defect-free Cu/Cu interface was formed at the lap interface due to the sufficient metallurgical bonding between the Cu column and the Cu plate, thereby effectively inhibiting the propagation of crack from the intermetallic compound layer at the lap interface between the Al and Cu plates. The tensile shear load of joint was increased first and then decreased when the rotational velocity and dwell time of welding tool increased, and the maximum value was 5.52 kN. The FSDRW joint presented a mixed mode of ductile and brittle fractures. 相似文献
15.
《中国航空学报》2023,36(5):508-521
It is difficult to gain effective Ti-Al fusion welding joints due to their differences in thermal properties and the appearance of brittle Ti-Al Intermetallic Compounds (IMCs). The experiments of laser fusion welding for TC4 titanium and 7075 aluminum alloy were carried out, temperature field and ductility/brittleness, as well as chemical potential of elements, were calculated, and the effect of adding Nb foil on mechanical properties of the weld was also investigated. The results suggested that Nb atoms tend to diffuse toward Al side, which is conducive to the participation of Nb in the metallurgical reaction and contributes to forming the Ti-Nb-Al IMC layer at the interface. As the thickness of Nb foil increases, the tensile-shear force of joint climbs first but then declines, and reaches the highest value of 1663 N with 0.10 mm-thickness Nb foil, representing 58.38% enhancement compared with the non-added one. Adding Nb foil slows down the heat transfer as a blocker, and thus both the melting amount of Al and the mixing area of Ti and Al decrease. In addition, Nb alloying reduces the brittleness of the Ti-Al compound. Hence, the joint properties of titanium/aluminum are improved with the addition of Nb foil. 相似文献
16.
以0.5mm厚6061铝合金和2mm厚T2紫铜搭接接头为研究对象,开展了无倾角微搅拌摩擦焊接试验,通过对搅拌工具材料选择、焊缝成形、接头性能分析,研究了其焊接工艺特性。试验结果表明,相比热作模具钢,采用高速工具钢制成的搅拌工具有更长的使用寿命。对于铝/铜搭接接头,无倾角微搅拌摩擦焊接能获得成形良好的焊缝,并且其工艺窗口宽泛,接头的力学性能良好,其承载能力能够达到铝合金母材的95%以上,但是当焊接速度为200mm/min时,主轴转速一旦超过25000r/min,焊缝表面将会出现沟槽缺陷。 相似文献
17.
《中国航空学报》2021,34(5):39-46
Effects of welding parameters on the microstructure and mechanical properties of Ti/Cu/Ni joint welded by electron beam were investigated. High welding heat input increased the melting quantity of Ti60 titanium alloy and promoted the formation of Ti–Cu intermetallic compounds (IMC) such as Ti2Cu and Ti3Cu4, increasing the brittleness of the joints. Low welding heat input was not conducive to the complete melting of the copper interlayer, and the unmelted copper reduced the performance of the joints. Under the optimal welding parameters, Ti–Ni IMCs in the weld would be replaced by (Cu, Ni) solid solutions ((Cu, Ni)ss). However, Ti–Cu IMC layers cannot be eliminated entirely by changing the welding parameters. The maximum tensile strength of the joints was 201 MPa. The fracture of the joints occurred at the Ti–Cu IMC layer, which was a typical brittle fracture. 相似文献
18.
针对变截面结构产品,提出了一种变截面搭接结构搅拌摩擦焊接方法,通过加装辅助板将整条焊缝焊接方向上补偿为等厚度。焊接采用一次定位焊接+二次定位焊接+正式焊接的工艺方式,一次定位焊为预定位,二次定位焊保证辅助板与试片主体结构之间形成有效连接,正式焊保证形成完整的焊缝。焊缝表面成形良好,超声相控阵检测无超标缺陷。通过对力学性能的分析,变截面搭接结构处焊缝与非搭接处焊缝和常规对接焊缝的力学性能基本相同,平均抗拉强度均达到母材的70%以上,平均延伸率均在5.8%以上。变截面搭接焊缝焊核处晶粒形态为细小的等轴晶,靠近轴肩影响区部分的晶粒尺寸大于靠近焊缝根部的晶粒尺寸,受再结晶影响,焊缝两侧热机影响区处辅助板搭接界面消失。 相似文献
19.
20.
针对7050铝合金搅拌摩擦焊接头,给出各组织特征区的定义,并对各特征区的组织状态、晶粒大小、沉淀强化相分布等进行深入的分析。为同材质的铝合金搅拌摩擦焊接头的综合性能评估提供更好的依据。 相似文献