QT500-7铸铁火焰钎焊方法及其对接头性能的影响

以B-Ag40CuZnCdNi合金为钎料,采用火焰钎焊方法实现了QT500-7铸铁的连接。研究了"三明治"法和毛细法两种钎料放置方式及不同加热时间对钎焊接头抗剪强度的影响,并对连接界面的微观组织进行了分析。结果表明:用"三明治"法放置钎料时,接头容易产生焊接缺陷,接头的承载能力低于母材;用毛细法放置钎料时,在足够长的加热时间条件下,液态钎料的填缝过程同时具有清洁钎缝间隙的作用,有利于得到钎缝细小平直且缺陷少的接头,因此抗剪强度得到提高,加热时间大于5min时,接头承载能力高于母材,但加热时间不足时反而不如"三明治"法的施焊效果。     

快冷钎料焊后“残余层”及元素扩散行为研究

使用A l-Cu共晶合金快冷钎料,以纯铝棒料为基体进行了真空钎焊.采用大间隙对接接头,使熔化后的钎料在毛细和重力作用下产生堆积,清楚地观察到了"钎料残余层"的存在.使用SEM和EDS对Cu元素的扩散现象进行了观察,初步研究和讨论了Cu元素在液相和固相扩散区域的不同扩散行为.实验结果表明:钎料熔化初期Cu元素在浓度梯度的驱使下向基体扩散,低熔点组分流向基体而高熔点组分逐渐堆积形成"钎料残余层".在基体深度方向上,Cu元素主要沿基体晶界扩散,且随扩散深度的增加呈明显的线性分布状态.     

真空技术及应用系列讲座 第十四讲:真空工程用焊接技术

(上接2006年第2期第64页)②对于不同的钎料与基材组合,其获得接头最高强度值的最佳间隙值范围各不相同,这与钎料和基材各自的物理化学性能以及在钎焊过程中的相互作用特性有密切关系。一般来说,钎料对基材的润湿性越好,这一间隙值就越小;钎料与基材相互作用强烈,间隙必须增大,因为填缝时基材的溶入会使钎料熔点提高、流动性下降。例如用铝基钎料钎焊铝合金时,基材向钎料中的溶解很强烈,为了保证填满钎缝,要求较大的间隙;相反,用银基或铜基钎料钎焊钢时,钎料与基材相互作用很弱,采用较小的间隙有助于加强钎料的毛细填缝。表12中所推荐的不同…     

CoFe基和Fe基高温钎料钎焊TiAl合金接头微观组织

为避免高温钎焊条件下钎料与TiAl母材发生过度反应,设计了CoFe基和Fe基两种高温钎料。在1100℃/10min和1200℃/10min条件下进行了钎料对TiAl合金的润湿性实验,在1180℃/5min条件下进行TiAl合金的真空钎焊实验。结果表明,1200℃/10min条件下两种钎料在TiAl合金上润湿角约为30°。与Ni基钎料相比,两种钎料与TiAl的界面反应程度得到缓解。CoFe基钎料对应接头界面主要形成Ti3Al,TiAl,硅化物和(Ti,Cr)-B,而在宽度较窄的(约10μm)钎缝中心形成了富Cr固溶体。Fe基钎料接头组织基本与CoFe基钎料接头类似,区别在于钎缝中心为残余钎料区,宽度约40μm,主要为Fe基固溶体。残余钎料区附近生成TiB和TiB2两种硼化物,与CoFe基钎料接头中硼化物相比,数量明显增多。     

Ag颗粒增强复合钎料钎焊接头蠕变断裂及强化机理研究

测定了不同应力和温度下Ag颗粒增强复合钎料及基体钎料63Sn37Pb钎焊接头蠕变寿命,分析了Ag颗粒增强复合钎料及基体钎料钎焊接头蠕变断裂机理.表明:Ag颗粒增强复合钎料钎焊接头蠕变寿命优于基体钎料;Ag颗粒表面Ag-Sn金属间化合物形成及Ag颗粒对富Pb层阻碍作用是复合钎料钎焊接头蠕变性能提高的主要因素;钎焊接头Cu基板上一薄层富Pb相区形成是蠕变裂纹主要原因.     

应力对Ag颗粒增强SnCu基复合钎料蠕变性能的影响

使用搭接面积为1mm2的单搭接钎焊接头,研究了恒定温度下应力对Ag颗粒增强SnCu基复合钎料钎焊接头蠕变寿命的影响,结果表明:Ag颗粒增强SnCu基复合钎料的蠕变抗力优于99.3Sn0.7Cu基体钎料;随着应力的增大,复合钎料及其基体钎料钎焊接头的蠕变寿命均呈下降趋势,且应力对复合钎料钎焊接头蠕变寿命的影响比基体钎料明显.     

Ni－Cr－Co－B钎料钎焊K3合金接头组织研究

采用金相分析、电子探针及Ｘ射线衍射等试验手段确定了Ｎｉ－Ｃｒ－Ｃｏ－Ｂ钎料及其钎焊的Ｋ３合金接头的相组成，研究了钎焊工艺参数和焊后扩散热处理对这类接头组织的影响，并与ＢＮｉ－ｌａ钎料钎焊的Ｋ３合金接头进行了对比。对采用Ｎｉ－Ｃｒ－Ｃｏ－Ｂ钎料和ＢＮｉ－ｌａ钎料钎焊的Ｋ３合金接头室温冲击韧性进行了对比评定。     

铟银软钎料的制备与钎焊性研究

实验利用高频感应熔炼方法制备了一系列不同Ag含量的InAg软钎料。利用手持式合金分析仪、XRD对钎料的成分和物相进行了分析。利用示差扫描量热仪（DSC）测试了不同成分钎料的熔点。测试了不同成分钎料的润湿性及接头剪切强度。结果表明：铟银软钎料由In与InAg2两相组成;通过控制加入Ag的量可以得到一定熔点的钎料;加入Ag降低了钎料的润湿性;加入Ag提高了接头剪切强度。     

温度对Cu颗粒增强复合钎料蠕变性能的影响

蠕变性能是影响钎焊接头可靠性的重要指标之一.采用搭接面积为1 mm2的单搭接钎焊接头,在恒定载荷下,测定了Cu颗粒增强锡铅基复合钎料钎焊接头的蠕变寿命,分析并讨论了温度对该复合钎料蠕变寿命的影响.结果表明:Cu颗粒增强的锡铅基复合钎料的蠕变抗力优于传统63Sn37Pb共晶钎料;钎焊接头蠕变寿命随温度的升高而降低,并且温度对复合钎料钎焊接头蠕变寿命的影响较传统63Sn37Pb钎料明显.     

TiC陶瓷/NiCrSiB/铸铁钎焊连接的界面组织和强度分析

采用NiCrSiB钎料对TiC陶瓷与铸铁进行钎焊连接,分析了接头的界面组织和剪切强度.结果表明:当连接规范一定时,在钎料内部、钎料与母材的界面处有TiC从TiC陶瓷侧扩散过来,同时在钎料内部和界面处有[Ni,Fe]和Ni基固溶体生成.当连接温度为1373K,连接时间为20 min时,接头的剪切强度最高可达78.6 MPa.     

铝合金超声波钎焊过程中液态钎料的填缝及界面润湿行为

研究了超声波振动作用下6061Al和2024Al合金焊缝中液态钎料的填缝过程,并分析了加热温度、焊缝预留间隙值对该过程的影响。结果表明,超声波振动作用下液态钎料的填缝行为与传统毛细填缝行为有很大差别,该条件下液态钎料在不润湿母材的基础上就迅速发生填缝过程,钎料初始液-气界面为凸状;随着填缝进行,填缝速度有所下降,填缝前沿钎料/母材界面润湿程度提高,钎料液-气界面形状转变为凹状。加热温度对超声波作用下液态钎料的填缝过程无明显影响,焊缝预留间隙值增加,钎料填缝长度减小,液-气界面形态发生变化。     

Ni-Cr-P焊膏钎焊C/C复合材料的组织和性能

用真空熔炼、惰性气体雾化法制备Ni-Cr-P金属粉末,再加入有机黏结剂高速搅拌,制备Ni14Cr10P膏状活性钎料。用制备好的焊膏真空钎焊C/C复合材料,测试钎焊接头的剪切强度,通过OM,SEM,EDS,XRD等对钎焊接头界面组织结构进行分析。结果表明:在钎焊温度1000℃、保温时间0.5 h条件下,获得的接头剪切强度达到28.6 MPa,然后随着钎焊温度上升或保温时间延长,钎焊接头强度下降;通过界面组织结构分析发现焊膏可以增加钎料层与C/C复合材料表面的接触面积,有利于堵塞C/C复合材料表面的孔隙。焊后在界面处形成了交错分布的Cr碳化物相缓冲层,使得界面呈现热膨胀系数梯度增加的结构,有助于缓解热失配,提高C/C复合材料钎焊接头强度。     

High strength electron beam welded titanium–stainless steel joint with V/Cu based composite filler metals

Composite V/Cu based filler metals for electron beam welding of titanium–stainless steel joint were designed, based on the element metallurgical compatibility. Powder metallurgy method was used to manufacture the filler metal. To determine the feasibility of these filler metals, microstructures were analyzed by optical microscopy, scanning electron microscopy and X-ray diffraction. Mechanical properties of the joints were evaluated by tensile strength tests. The feasibility of the Cu/V filler metal was poor for the differences in physical properties between copper and vanadium, vanadium and titanium. A non-fusion defect was produced in the joint under low heat input, and cracking occurred in the joint under higher heat input due to the continuously distributed brittle TiCu, TiFe and τ₂ compounds. However, such defects were eliminated using a powder metallurgical V/Cu–V filler metal. A joint with a tensile strength of 395 MPa, 72% of that of the stainless steel was obtained. And almost no intermetallics were detected in Ti/V/Cu–V/Fe joint.     

Study on filler metal (Ni-Fe-C) during GTAW of WC-30Co to 45″ carbon steel

In this study, WC-30Co cemented carbide is welded to carbon steel by the gas tungsten arc welding (GTAW) using Ni-Fe filler metal and Ni-Fe-C filler metal. The butt joints manifest more embrittling η-phase carbides with Ni-Fe filler metal, while less even no η-phase carbides with Ni-Fe-C filler metal. The η-phase carbides morphology and formative factors were further discussed using Backscattered Electron Imaging (BEI) method; Electronic probe microanalysis (EPMA) is used to determine the distribution of elements Ni, Fe, C, W and Co across the HAZ (Heat Affected Zone) near WC-30Co/welded-seam interface. The hardness profile is determined using micro-hardness measurements and bend strength value of butt joint with different filler metal is tested by four-point bend strength test. The hardness profile and bend strength value agree with the information obtained from microstructure analysis, BEI analysis and X-rays phase analysis very well. The results show: (1) butt joint of WC-30Co/carbon steel can be obtained using GTA with Ni-Fe-C filler metal; (2) the addition of carbon content to Ni-Fe filler metal leads to less even none η-phase multi-carbides strongly, and mechanical property of butt joint can be improved.     

钛基非晶钎料真空钎焊TA15钛合金的研究

针对TA15薄壁及蜂窝等复杂结构件设计和焊装的需求,本文采用急冷技术成功制备Ti-Zr28-Cu15-Ni15(1#),Ti-Zr21-Cu20-Ni15(2#)非晶箔带钎料.通过SEM,EDS和XRD等分析测试手段,分析了钎料及钎焊工艺对TA15钛合金钎焊接头界面组织和力学性能的影响.研究结果表明:两种钛基非晶钎料成带性能良好,与相同成分晶态钎料相比,液相线温度降低,熔化温度区间减小.钎料对母材有明显润湿作用,并且2#钎料共晶成分的提高使得其润湿性和非晶形成能力较1#钎料优异.1#钎料对接接头室温拉伸强度在970℃/30min工艺下达到最高325MPa,2#钎料在950℃/30min工艺下接头强度达到最高359MPa,并且其接头力学性能的稳定性较1#钎料要高.对比相同工艺下不同钎料焊缝组织,钎缝均为α+β层片状组织,2#钎料界面处Ti-Cu和Ti-Ni金属间化合物含量较少.     

The effect of interlayer metals on the strength of alumina ceramic and 1Cr18Ni9Ti stainless steel bonding

The effects of interlayers of molybdenum and copper on the strength of alumina ceramic and 1Cr18Ni9Ti stainless steel bonding with Ag₅₇Cu₃₈Ti₅ filler metal were investigated. The interfacial morphologies were observed and analysed by scanning electron microscopy and energy dispersive X-ray (EDX) analysis, respectively. The joint strength was examined by shear tests. When using a molybdenum interlayer, the joint strength could be greatly improved because molybdenum not only reduced the interfacial residual stress, but also did not affect the interfacial reaction between the ceramic and the filler metal, and the maximum value was obtained when it was about 0.1 mm thick. When using copper as an interlayer, the joint strength was not increased but decreased, because copper reduced the activity of titanium in the filler metal, resulting in an insufficient interfacial reaction between the ceramic and the filler metal and the formation of poor interfacial adhesion. Therefore, in selecting an interlayer metal to reduce or avoid interfacial residual stress in joining ceramics to metals, in which the interfacial reaction of ceramic and filler metal is important to the joints, the interaction of interlayer metal and filler metal must be considered.     

BCu50ZnMnNiSi多元铜基钎料的研究

提出了一种含Ｎｉ、Ｓｉ的适合钎焊合金白口铸铁的Ｃｕ基ＣｕＺｎＭｎ多元钎料,并对ＢＣｕ５０ＺｎＭｎＮｉＳｉ钎料的熔化特性、钎焊工艺性能、钎料组织以及力学性能进行了研究。研究结果表明,与普通ＣｕＺｎ合金钎料比较,ＢＣｕ５０ＺｎＭｎＮｉＳｉ钎料钎焊冶金特性优异,界面冶金结合致密,尽管钎料中含有多元合金元素,钎焊后钎缝仍有较好的塑必     

Carbide precipitates and mechanical properties of medium Mn steel joint with metal inert gas welding

Medium Mn steel was metal inert gas(MIG)welded with NiCrMo-3 and 307Si filler wires.The effect of filler wires on the microstructure and mechanical properties of joint was investigated,and the carbide precipitates were contrastively discussed.The results revealed that the microstructure of weld metal,heat-affected zone and base metal are austenite.Obvious grain coarsening occurred in the heat-affected zone(HAZ),and the maximum grain size grew up to 160 pm.In HAZ,C and Cr segregated at grain boundaries,the carbides was identified as Cr7C3.The dispersive(Nb,Mo)C phase was also found in weld metal with NiCrMo-3 filler wire.All the welded joints failed in HAZ during tensile tests.The tensile strength of welded joint with NiCrMo-3 filler wire was 675 MPa,which is much higher than that with 307Si filler wire.In comparison to base metal,higher microhardness and lower impact toughness were obtained in HAZ for these two welded joints,which was attributed to the precipitation of Cr7C3 phase and grain coarsening.The impact toughness around the fusion line is the worst for these two welded joints.     

Evaluation of transient liquid phase bonding between nickel-based superalloys

Induction brazing of Inconel 718 to Inconel X-750 using Ni-7Cr-3Fe-3.2B-4.5Si (wt.-%) foil as brazing filler metal was investigated in this paper. Brazing was conducted at the temperature range 1373–1473 K for 0–300 s in a flow argon environment. Both interfacial microstructures and mechanical properties of brazed joints were investigated to evaluate joint quality. The optical and scanning electron microscopic results indicate that good wetting existed between the brazing alloy and both Inconel 718 and Inconel X-750. Microstructures at joint interfaces of all samples show distinct multilayered structures that were mainly formed by isothermal solidification and following solid-state interdiffusion during joining. The diffusion of boron and silicon from brazing filler metal into base metal at the brazing temperature is the main controlling factor pertaining to the microstructural evolution of the joint interface. The element area distribution of Cr, Fe, Si, Ni and Ti was examined by energy dispersive X-ray analysis. It was found that silicon and chromium remain in the center of brazed region and form brittle eutectic phases; boron distribution is uniform across joint area as it readily diffuses from brazing filler metal into base metal. The influence of heating cycle on the microstructures of base material and holding time on the mechanical properties of brazed joint were also investigated.