铝/铝钎焊用Al-Si-Zn系钎料的研究

采用Al-Si-Zn系钎料对铝-铝金属进行火焰钎焊和炉中钎焊试验,通过XRD,SEM和EDS对钎料和接头的微观组织进行分析,并检测接头的力学性能。此外,通过盐雾腐蚀试验和电化学腐蚀试验分别对接头和钎料的耐蚀性进行了分析。研究结果表明:Al-5.1Si-40.2Zn钎料配合CsF-AlF_3无腐蚀钎剂钎焊的铝-铝接头具有优良的抗腐蚀性能,接头经过30天盐雾腐蚀试验后,接头抗剪强度基本没有下降。     

铜铝钎焊接头腐蚀机理分析

通过感应钎焊获得了Zn-2Al,Zn-2Al-1.2Cu,Zn-13Al-5Ag三种不同的铜铝钎料接头,借助试验手段研究了不同钎料的电化学腐蚀行为以及腐蚀前后不同接头的力学性能. 结果表明,在3.5%NaCl溶液中,三种钎料的耐腐蚀性能从高到低依次是Zn-13Al-5Ag,Zn-2Al-1.2Cu和Zn-2Al钎料. 腐蚀后三种钎料接头的抗剪强度下降率分别为29.4%,24.5%和23.7%,这是由于钎料接头铜侧界面处金属间化合物为高电位阴极相,与钎缝中α-Al相形成高电位差,从而导致抗剪强度下降.Zn-13Al-5Ag钎料接头钎缝中AgZn3增强相不易发生阳极溶解进入溶液,该钎料中弥散分布的细微的α-Al相阳极溶解后在接头表面形成钝化膜,使反应不易进行,因此其抗腐蚀性能最好     

铜/铝钎焊用Zn-Al钎料的电化学腐蚀性能研究

采用铸锭冶金法,在高频感应炉中制备了铜/铝钎焊用Zn-22Al钎料,通过浸泡腐蚀试验、电化学腐蚀试验对添加Mg元素的钎料的耐蚀性能进行了评价分析,并探讨了其腐蚀机理.研究结果表明,添加Mg元素可显著提高钎料基体的电极电位,从而显著提高钎料本身的耐腐蚀性能,并不会显著降低铜/铝接头的强度.加入Mg元素的Zn-22Al钎料,配合CsF-AlF3无腐蚀中温钎剂,采用高频感应加热钎焊连接铜/铝管,通过浸泡腐蚀试验后,仍可获得高剪切强度的接头.     

铁基钎料成分对304不锈钢钎焊接头组织和性能的影响

通过加入B,Mo元素研制了四种新型铁基钎料,并在1050℃下进行了304不锈钢真空钎焊试验。对比了四种自制铁基钎料与商用F300钎料钎焊后接头的显微组织和耐腐蚀性能,以及抗剪强度和钎缝中心硬度等性能。结果表明:B元素有利于降低钎料合金的熔点,而Mo元素的加入使钎缝组织晶粒细化,提高了接头的抗剪强度和耐腐蚀性能。加入B,Mo元素后的钎料,钎缝组织中大部分的结晶区域晶粒均匀、细小,其中韧性的富FeCrNi相包围着硬脆的富FeCrNiP相,呈现鱼骨状的明暗交织区域。接头的最大抗剪强度达到了57.6MPa,在10%硫酸溶液中的耐腐蚀性能优于F300钎料。     

SiCp/Cu复合材料的真空钎焊

对冷压烧结结合热挤压工艺制备的SiC/Cu复合材料,选用Ti和AgCuTi为钎料,采用不同的工艺进行真空钎焊试验.用金相显微镜和扫描电镜对母材和钎焊接头的剪切断口形貌进行分析,利用电子万能试验机对钎焊接头进行抗剪强度测试,将接头抗剪强度与母材抗剪强度进行对比以评判钎缝质量.结果表明,用Ti为钎料连接SiCp/Cu复合材料的连接状况要优于AgCuTi钎料,且连接温度850℃,保温时间为20 min时,抗剪强度最大为70.5 MPa,与母材抗剪强度相当;随着铜基复合材料中SiCp含量不断增加,钎焊接头室温抗剪强度不断下降,当SiCp含量超过10%时,抗剪强度快速下降.     

铝铜钎焊用Zn-Al钎料的研究

研究了Al含量对铝铜异种金属钎焊用Zn-Al钎料的铺展性能和铝铜焊接接头强度的影响。结果表明。Al含量在15wt％以上时,钎料在铜上铺展性较好,含Al10wt％左右的钎料所焊铝铜接头的强度最好。采用含Al10wt％的Zn-Al钎料。配合CsF-AlF3无腐蚀中温钎剂,采用高频感应加热钎焊连接铜铝管,能获得高压下不漏气的理想接头。     

Al-Si-Cu-Zn急冷钎料钎焊铝及铝合金的界面结构及强度

采用Al70Si7.5Cu20Zn2.5和Al65Si10Cu20Zn5两种急冷钎料钎焊L2纯铝和6063铝合金,研究钎焊接头的界面微观结构和力学性能.结果表明,急冷钎料钎焊接头由母材、界面区和钎缝中心组成.界面区为αAl固溶体,钎缝中心组织为αAl固溶体 θ(Al2Cu)相 Si相.采用Al65Si10Cu20Zn5急冷钎料钎焊的接头抗剪强度均高于Al70Si-7.5Cu20Zn2.5急冷钎料钎焊的接头强度;匹配氯化物钎剂钎焊的接头强度均高于氟化物钎剂.在相同的工艺条件下,采用急冷钎料钎焊的L2纯铝接头,其抗剪强度都明显高于相应的常规钎料,其增加值在40%左右.     

1060铝钎缝耐腐蚀性分析

以1060纯铝作为母材,选取Zn-Al-Ag,Zn-Al,Sn-Zn,Zn-Cd-Ag等4种钎料,采用氧乙炔火焰钎焊工艺制备钎焊接头,采用盐浴浸泡方法加速腐蚀,分析了4种钎缝的耐腐蚀性. 通过宏观形貌观察、极化曲线测试、失重分析和显微组织观测,综合评价了钎缝的耐腐蚀性. 结果表明,在所分析的3个合金系中,Zn-Al系钎料钎缝耐腐蚀性能较好,Zn-Cd-Ag钎缝耐腐蚀性次之,Sn-Zn钎缝的耐腐蚀性最差. 对盐浴腐蚀而言,Zn82Al13Ag5比Zn98Al更耐腐蚀. 而对于电化学腐蚀而言,银的加入能够进一步提高Zn-Al系钎料钎缝的耐腐蚀性能.     

急冷型Sn-Ag-Cu系钎料钎焊接头力学性能与显微组织

采用单辊法制备了急冷型Sn-Ag-Cu系钎料合金,在对其进行熔化温度特性和XRD分析检测后,进行了钎焊工艺试验,并对所得接头的抗剪强度和显微组织进行了测试分析,研究了钎焊温度对接头组织性能的影响。结果表明:在不同的钎焊温度条件下,接头界面处金属间化合物的形成及分布是不同的,并由此导致了接头抗剪强度的变化。     

热处理工艺对截齿钎焊接头强度的影响

为获得采煤机用截齿钎焊接头的优良性能，作者研究了钎焊后热处理工艺参数对钎缝抗剪强度的影响。试验表明，高温区停留时间在保证钎焊时钎料充分熔化的前提下越短越好；冷却速度对接头的强度有较大影响，一般情况下，钎焊后由880℃冷却到200℃的时间应控制在5～20min之间；回火温度在350～450℃之间抗剪强度有低谷区。截齿钎焊采用HL105钎料，配以合适的钎剂能获得较理想的接头性能。     

Corrosion resistance of ultrasonic soldered aluminium joint using Zn-based solder alloy

In order to obtain high strength aluminium butt joints with high corrosion resistance, ultrasonic soldering of 1070 and 5056 rods was conducted using quasi-melting Zn–18Sn (mass%) alloy and Zn–38A1 alloy. Ultrasonic vibrations were applied at soldering temperature ranging 533–723 K through aluminium rods without using of a solder bath. To evaluate the corrosion resistance of solder joints, tensile tests were conducted after immersion in a 5% NaCl aqueous solution. Though joint strength decreased with an increase in immersion time in the NaCl aqueous solution because of corrosion in the joints, corrosion resistance of 5056 joints with Zn–38A1 alloy was higher than that of joints with Zn–18Sn alloy irrespective of aluminium base material. The strength of joints with Zn–18Sn alloy rapidly decreased by immersion in the NaCl aqueous solution. In these joints, corrosion occurred locally in the soldered interface. Corrosion potential of these joints was unusually lower than that of the solder alloy. In contrast, corrosion occurred slowly in the solder layer in 5056 joints with Zn–38A1 alloy. Corrosion potential of the joints was equivalent to that of the solder alloy.     

镍基、铁镍基耐蚀合金的焊接工艺及控制要点

镍基、铁镍基耐蚀合金常用于高温、高压、介质有热腐蚀作用等十分苛刻的工作条件下,对材料使用性能要求很高。其焊接过程中的主要问题是焊缝结晶裂纹、过热区晶粒粗大及焊接接头的等强性。实践表明,通过选用合适的焊接材料,制定合理的焊接工艺方案和工艺评定试验,并结合切实可行的工艺控制要点,能够满足产品的设计要求和实际的使用需要。     

等离子弧焊Q345B和430不锈钢异种接头的微观组织与性能

摘要： 采用等离子弧焊对3 mm厚的Q345低合金钢与430不锈钢进行异种钢焊接,并对接头微观组织、力学性能及耐腐蚀性能进行了研究。结果表明,当转弧电流为100 A时,等离子弧焊Q345B/430异种钢接头的焊缝组织为均匀分布的马氏体及针状铁素体,焊接接头综合性能优良。随着电流的增大,焊缝组织转变为粗大板条马氏体及铁素体。两侧热影响区组织均发生一定程度的粗化,且Q345B侧热影响区出现魏氏组织。焊接接头于焊缝处显微硬度最大,不同转弧电流条件下异种钢显微硬度分布趋势大致相同。不同转弧电流下,焊接接头抗拉强度均与430不锈钢相近,且均断裂在靠近焊缝的430母材侧,转弧电流为100 A时接头抗拉强度最大值427 MPa。焊接接头的耐腐蚀性能与焊接电流呈负相关趋势。 创新点： 试验结果为铁素体低合金钢与铁素体不锈钢异种钢接头的应用提供了工艺数据与支撑。     

Zur Schwingungsrißkorrosion feuerverzinkter Schweißverbindungen unter Dauertauch- und Wechseltauchbeanspruchung

Corrosion fatigue of hot dip galvanized welded joints with permanent and alternate immersion Zink-coatings as corrosion protection of fatigue loaded welded constructions are of increasing importance. As corresponding design concepts in general are not available, corrosion fatigue tests with constant and variable amplitudes at filled welded joints are carried out under permanent immersion in artificial seawater or under alternate immersion in 5%-NaCl-solution including a lot of material, geometrical and fabricating parameters. The analysis of the results yields reliable informations with respect to the influence of hot dip galvanizing on the corrosion fatigue of welded joints.     

高压干法X65管线钢GMAW焊接接头在模拟海水中的腐蚀行为

高压干法熔化极气体保护焊(简称GMAW)在海底油气管道等水下构件的组装和维修中有着非常广泛的应用,焊接接头在海水中的腐蚀行为对于海底输油管道的安全运行至关重要.通过模拟浸泡试验和极化曲线法研究不同环境压力下(常压,0.3 MPa,0.5 MPa) X65管线钢干法GMAW焊接接头在人工海水中的腐蚀行为及机理. 结果表明,与焊缝和母材相比,热影响区的耐蚀性最差,且环境压力对焊接接头的腐蚀性能影响不明显. X65管线钢干法GMAW焊接接头在人工海水中的腐蚀形式以点蚀为主,在浸泡后期出现严重的局部腐蚀;腐蚀产物由FeOOH,Fe₂O₃,Fe₃O₄组成,腐蚀产物层在浸泡初期起到减缓金属腐蚀的作用,但随着浸泡时间延长,腐蚀产物层的致密性降低,其下的金属接头容易遭受到Cl?的破坏,使局部腐蚀过程加剧.     

铝钢电磁脉冲焊接接头中性盐雾腐蚀行为

为了获得铝钢电磁脉冲焊接接头中性盐雾介质的腐蚀过程及机理,对5%NaCl腐蚀后的焊接接头进行拉剪试验,并采用带能谱的扫描电子显微镜进行断口微观形貌分析.结果表明,铝钢电磁脉冲焊接接头中性盐雾腐蚀3天后的抗剪强度由原态74 MPa降为33 MPa,为原态的44.6%,腐蚀周期7天时,焊缝完全失效;在焊缝外围,粒子流击碎铝板表面氧化物生成粒状腐蚀物NaAlO₂,焊缝上FeAl₃破碎,露出铝被快速腐蚀为Al(OH)₃;在铝板表面撞击产生凹坑和嵌入钢板表面片状铝的位置最先被腐蚀,NaCl液体堆积并在表层金属下流动腐蚀,且沿着腐蚀坑互连方向扩展,再向焊缝存在FeAl₃相的连接区延伸;当氧化膜或焊缝被NaCl介质腐蚀抬起且破碎后,向着铝基体深层腐蚀,形成多而深的沟壑或凹坑,这成为接头快速失效的主要腐蚀机理.     

Fabrication and performance evaluation of dissimilar magnesium–aluminium alloy multi-seam friction stir clad joints

This investigation is aimed to establish empirical relationships between continuous multi-seam friction stir cladding process parameters (i.e., rotational speed, welding speed and shoulder overlap ratio) and the quality characteristics (bond tensile strength, shear strength and corrosion) of dissimilar magnesium–aluminium alloy clad joints. The influence of considered process parameters on the clad properties was reported. Furthermore, multi-criterion optimization procedure was used to obtain ideal processing conditions, which can yield higher interface strength and lower corrosion rate of fabricated composite plate. Results indicate that, the aluminium-rich thin continuous layer, Mg-rich irregular shaped regions consists of Al₃Mg₂ and Al₁₂Mg₁₇ intermetallic compounds and nature of mechanical interlocking has great influence on the joint interface strength. On the other hand, the corrosion resistance of the clad joints is greatly affected by the amount of magnesium mixed with top aluminium sheet during friction stirring. Also, bend testing shows that, the cladded joints exhibit excellent ductility.     

Die-attach for power devices using the Ag sintering process: Interfacial microstructure and mechanical strength

The sintering reactions and mechanical reliability of Ag sinter paste with three different surface finishes, Cu, Ag, and electroless nickel-immersion gold, were evaluated during the sintering process. We compare the sintering reaction behaviors of the three sintered joints and identify the relationship between the sintering behavior and the sintered Ag/substrate compatibility. Inter-diffusion behaviors result in of good metallurgical bonding during the Ag sintering process in the three sintered joints. The shear strength increases on increasing the bonding pressure, irrespective of the surface finish. The surface finish material of the substrate strongly affects the shear strength of the Ag sintered joints. The Ag finished joint exhibits superior interfacial stability and shear strength compared to the Cu and Au finished joints.     

利用电化学方法研究纯镁在薄液膜下的腐蚀行为Ⅱ-薄液膜对纯镁腐蚀阳极过程的影响

利用电化学噪声研究了纯镁在不同厚度薄液膜下的腐蚀行为.结果表明:与本体溶液相比,薄液膜对纯镁腐蚀的阳极过程有使点蚀的孕育速度减缓作用的同时还有使点蚀生长的概率增加的作用;薄液膜下纯镁表面产生的亚稳态点蚀牛长成稳态点蚀的概率比本体溶液下的大.点蚀孕育速度比点蚀生长概率对阳极过程的影响更大;这导致r薄液膜下纯镁腐蚀的阳极过程减缓.     

考虑残余应力的激光搭接焊接头拉伸和疲劳试样宽度标准化

抗剪强度和疲劳强度是激光搭接焊接头性能的两个最重要指标。关于激光搭接焊接头的拉伸和疲劳试样的宽度选取,目前还没有相应的标准进行规定。以不锈钢薄板激光搭接焊接头为研究对象,通过残余应力数值与试样宽度变化关系的测定,确定了考虑和不考虑残余应力影响的拉伸和疲劳试样合理宽度,比较了有无残余应力试样抗剪强度的区别。结果表明,残余应力通过改变焊接接头受力状态和微观变形均匀性降低了薄板激光搭接焊接试样的抗剪强度。