Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with copper interlayer sheet

Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with a copper sheet as interlayer was carried out.Microstructures of the joint were studied by optical microscopy(OM),scanning electron microscopy(SEM) and X-ray diffractometry(XRD).In addition,the mechanical properties of the joint were evaluated by tensile test and the microhardness was measured.These two alloys were successfully welded by adding copper transition layer into the weld.Solid solution with a certain thickness was located at the interfaces between weld and base metal in both sides.Regions inside the weld and near the stainless steel were characterized by solid solution of copper with TiFe2 intermetallics dispersedly distributed in it.While weld near titanium alloy contained Ti-Cu and Ti-Fe-Cu intermetallics layer,in which the hardness of weld came to the highest value.Brittle fracture occurred in the intermetallics layer when the joint was stretched.     

采用不同结构Cu/V填充层的钛合金/不锈钢电子束焊接试验

对采用不同结构Cu/V填充层的钛合金与不锈钢电子束焊接头横截面形貌、微观组织及力学性能进行了分析.结果表明,采用片层结构的Cu/V填充层进行焊接时,焊缝组织由钒基固溶体、铜基固溶体及铁基固溶体组成,但由于焊缝底部有钢层未熔,形成未熔合缺陷,接头强度为288 MPa.采用楔形结构的Cu/V填充层,在保持接头固溶体过渡组织结构特征的同时,消除了未熔合缺陷,接头抗拉强度达到385 MPa.未熔钒层为接头力学性能薄弱区域,不同结构填充层的焊接接头断裂均发生于未熔钒层处.     

镍铝青铜过渡层对钛合金/不锈钢异种材料激光焊接头组织与力学性能的影响

对3?mm厚TC4钛合金/15-5PH不锈钢异种材料进行了添加镍铝青铜(nickel?aluminum?bronze,NAB)过渡层的激光填充材料焊接,研究了NAB过渡层对接头成形、微观组织与力学性能的影响.?结果表明,添加NAB过渡层的TC4钛合金/15-5PH不锈钢异种材料激光焊接获得了良好成形的全熔透接头,接头抗...     

填充金属对钛合金与不锈钢电子束焊接的影响(英文)

采用Ni、V、Cu等填充材料进行钛合金与不锈钢的电子束焊接实验。采用光学显微镜、扫描电镜及X射线衍射对接头的微观组织进行分析。通过抗拉强度和显微硬度评价接头的力学性能,分析讨论填充材料对钛/钢电子束焊接接头微观组织和力学性能的影响。结果表明:填充材料有助于抑制Ti-Fe金属间化合物的产生。所有接头均由固溶体和界面化合物组成。对于不同的填充材料,固溶体和界面化合物种类取决于填充材料与母材之间的冶金反应。对于Ni、V及Cu填充材料,界面化合物分别为Fe2Ti+Ni3Ti+NiTi2,TiFe和Cu2Ti+CuTi+CuTi2。接头抗拉强度主要取决于金属间化合物的脆性。采用Cu填充金属的接头抗拉强度最高,约为234 MPa。     

电镀阻隔层对钛/钢电子束焊接接头性能的影响

采用电子束熔化焊、电子束阻隔焊和电子束阻隔熔-钎焊方法来实现钛合金与不锈钢异种金属之间的连接。研究发现钛合金与不锈钢连接界面处产生的脆性金属间化合物是影响接头性能的关键因素。采用电子束直接熔化焊和阻隔熔化焊钛合金和不锈钢时,接头界面会产生贯穿性裂纹导致焊缝直接断裂。电子束阻隔熔-钎焊中利用熔化的不锈钢润湿未熔化的钛合金母材,并采用Ag、Cu作为中间层添加元素,在结合界面处形成了很好的阻隔屏障,减少了Ti/Fe界面的金属间化合物的产生,减缓了应力,实现了钛合金与不锈钢的冶金结合,接头抗拉强度约为100 MPa。电子束阻隔熔-钎焊得到的钛合金/不锈钢异种金属焊接接头焊缝正反面成形良好,X射线探伤未发现裂纹和气孔缺陷。     

添加QCr0.8阻隔层的钛/钢电子束焊接接头组织与性能

采用1.5 mm厚QCr0.8铬青铜作为阻隔层进行了TA15钛合金与304不锈钢的电子束焊接,重点分析了焊接接头的横截面形貌、微观组织和力学性能。结果表明,焊缝中存在约0.5 mm宽的未熔QCr0.8阻隔层,实现了Ti元素与Fe元素的物理隔离,避免了Ti-Fe化合物的形成。铜/钢侧焊缝由铜基固溶体与铁基固溶体组成。而钛/铜侧焊缝中V元素的加入很好地抑制了Ti-Cu界面化合物的大量生成,焊缝组织由铜基固溶体、(Ti,V)基固溶体及少量Ti-Cu化合物组成,提高了该区域的强度和塑性。未熔铜阻隔层在热作用下发生软化,接头拉伸断裂发生在未熔的QCr0.8上,接头抗拉强度为293 MPa,为塑性断裂模式。     

钛合金/不锈钢冷金属过渡焊接头组织及性能

采用铜基填充金属对TC4钛合金、304不锈钢进行冷金属过渡焊接,分析了钛合金/不锈钢接头的界面组织、力学性能及腐蚀性能. 结果表明,采用冷金属过渡连接方法实现了TC4钛合金和304不锈钢的焊接. 钛合金/不锈钢接头主要由焊缝金属、不锈钢-铜焊缝界面和钛合金-铜焊缝界面组成. 钛合金/不锈钢接头的拉剪强度为306 MPa. 由于钛合金-铜焊缝界面中Ti-Cu,Ti-Fe金属间化合物的生成,接头沿钛合金-铜焊缝界面反应层发生脆性断裂. 钛合金/不锈钢接头在人工海水溶液中发生了电偶腐蚀,其腐蚀机理为阴极区发生氧的还原反应和析氢反应,阳极发生焊缝金属的氧化,钛合金母材表面TiO₂氧化膜的形成,不锈钢母材发生点蚀.     

Contact Reactive Joining of TA15 and 304 Stainless Steel Via a Copper Interlayer Heated by Electron Beam with a Beam Deflection

TA15 titanium alloy and 304 stainless steel were joined via a copper interlayer heated by electron beam with a beam deflection towards the stainless steel. Microstructures of the joints were analyzed by optical microscopy, scanning electron microscopy, and X-ray diffraction. The tensile strengths of the joints and the ultramicrohardness of the intermetallic compounds were also measured. The results showed that the joint was formed by three kinds of metallurgical processes. Copper interlayer and TA15 were joined by contact reaction with the reaction products of CuTi, Cu₄Ti₃, and Cu₂Ti. While copper interlayer and 304 stainless steel were joined by fusion and solid state diffusion process. Tensile strength of the joint can reach to 300?MPa, equivalent to 55% of that of 304 stainless steel. Furthermore, the tensile strength was mostly dependent on the volume of the unmelted copper sheet, although the intermetallics layer was the weakest location in the joint.     

TiNi形状记忆合金与不锈钢激光焊接头裂纹分析及防止措施

采用激光焊对TiNi形状记忆合金与不锈钢异种材料进行焊接,用扫描电镜和激光共聚焦显微镜研究了TiNi合金/不锈钢接头裂纹及断口特征,分析了焊缝裂纹的形成机理,并提出了防止裂纹的措施.结果表明,裂纹多以微裂纹的形式出现于焊缝中心和TiNi合金侧熔合区.焊缝中存在大量的脆性化合物是产生裂纹的内在原因,接头受到拉伸应力是产生裂纹的必要条件,焊缝裂纹是二者共同作用的结果.通过焊接区加镍和钴中间层材料、改变激光光斑位置、焊接区施加轴向力及优化激光焊接参数的方法均能在一定程度上改善焊缝金属的裂纹敏感性,其中加金属中间层效果更为明显,加镍和钴中间层后,接头抗拉强度分别达到372和347 MPa,比未加中间层的接头的抗拉强度分别提高98.9%和85.6%.     

Effect of laser offset on microstructure and mechanical properties of laser welding of pure molybdenum to stainless steel

Direct welding of Mo and stainless steel is exceptionally difficult due to intrinsic brittleness of Mo and the formation of brittle Fe-Mo phases. To explore the feasibility of welding of Mo and stainless steel, the laser offset method was used in this study. Experimental results show that the offset of the laser beam toward stainless steel has a positive effect for the quality of Mo/Fe dissimilar joint. As the laser beam shifts from the Mo side to the stainless steel side, the formation of welding defects and Fe-Mo intermetallic compounds (IMCs) are effectively restricted because of the decrease amount of molten Mo. The decrease of Fe-Mo IMCs contributes to the reduction of hardness in the joints. With an increase of laser offset, the thickness of Fe-Mo IMCs layer decreased, consequently the tensile strength of joints increased first and then decreased in the laser offset range of 0.2–0.5 mm. The highest tensile strength of the joints is 290 MPa at the laser offset of 0.3 mm. All joints failed in the Fe-Mo IMCs layer with brittle fracture mode during tensile tests, indicating the weakest zone of the joint was Fe-Mo IMCs layer. A sound weld of Mo and stainless steel can be obtained if an appropriate thickness of Fe-Mo IMCs layer is produced by adjusting the laser offset.     

30CrMnSi/Cu/V/TC4电子束焊接试验研究

使用Cu/V中间层实现了30CrMnSi合金钢与TC4钛合金的电子束焊接,探究了接头组织和性能特征。结果表明,通过添加Cu/V过渡层金属可以避免Ti-Fe元素的直接混合反应生成脆硬的金属间化合物。焊缝不同区域分布着不同组分及性能的特征相,靠近钢侧焊缝为偏聚形成的富Fe相与富Cu相,靠近钛侧焊缝在形成Ti-V固溶体的同时也形成了少量Ti-Cu金属间化合物。接头的抗拉强度最高为418 MPa,接头失效于焊缝与30CrMnSi母材界面处的熔合线位置。     

添加铜填充层的Ti-15-3钛合金与304不锈钢电子束焊接过程中的温度与应力场(英文)

采用铜填充金属对Ti-15-3钛合金与304不锈钢进行电子束焊接,对Ti/Fe和Ti/Cu/Fe接头在焊接过程中的温度场和应力场进行数值模拟和试验测量。结果表明,高斯旋转体热源适用于电子束焊接过程的模拟。温度场对于焊缝中心呈非对称分布,钛侧的温度高于不锈钢侧的。热应力同样呈非对称分布,残余拉应力主要存在于不锈钢侧。铜填充金属的加入,降低了焊接过程中的峰值温度、温度梯度以及残余应力,纵向和横向残余拉应力分别降低了66MPa和31MPa。从温度场和应力场的角度可以看出,铜合金是一种较好的Ti-15-3钛合金与304不锈钢电子束焊接的填充金属材料。     

钛合金板与不锈钢丝网异质接头焊接

采用不同的滚焊和真空扩散焊工艺研究了TC4钛合金板与00Cr18Ni13不锈钢丝网的异质接头的焊接问题.焊缝显微分析显示,无论是滚焊或真空扩散焊,无论焊接参数大小,都无法避免异质接头直接扩散焊时产生内应力和脆性的金属间化合物相,并形成裂纹.滚焊和较小的焊接参数只能减少焊接缺陷的产生,较大的焊接参数的扩散焊直接导致未熔合和开裂.采用中间过渡层并产生微观机械咬合的焊接接头性能较好.     

钒/镍复合中间层扩散焊接钨与钢的界面结构及力学性能

通过添加钒/镍复合中间层,在1 050℃/10 MPa/1 h的工艺条件下,对钨/钢异种材料进行真空扩散焊接.采用扫描电镜(SEM)、能谱仪(EDS)、电子探针(EPMA)、纳米压痕、X射线衍射对接头的微观组织、元素分布及显微硬度进行分析和测试;对焊接接头的拉伸性能进行测试,并对拉伸断口的形貌特征,元素分布及物相组成进行分析.结果表明,采用钒/镍复合层可实现钨与钢的可靠焊接;钨/钢焊接接头界面区由钨-钒固溶体层、未反应的钒层、钒-镍界面层、未反应的镍层、镍-铁固溶体层五部分组成,其中钒-镍界面层结构为碳化钒层/钒-镍金属间化合物和碳化钒混合层/钒-镍金属间化合物层;钒/镍界面由于硬脆碳化物与金属间化合物的产生,具有最高的显微硬度,硬度高达9.7 GPa;接头强度达164 MPa,断裂点位于含脆性相碳化钒及钒-镍金属间化合物的钒/镍界面.     

束流偏移对钒合金与不锈钢电子束阻隔熔化焊接头性能的影响

以金作为中间层采用电子束阻隔熔化焊方法来实现V-5Cr-5Ti钒合金与HR-2不锈钢之间的连接,研究电子束流的偏移对接头性能的影响.结果表明,不偏移电子束流(偏移距离d=0)焊接得到的钒合金与不锈钢接头界面将产生贯穿性裂纹,直接导致焊接失败.通过电子束流的偏移(偏移距离d等于束斑半径)一定程度降低了结合界面金属间化合物的产生,实现了钒合金与不锈钢的冶金结合.金作为中间层添加元素,很好地抑制了V/Fe界面的金属间化合物的产生,显著提高了接头性能,接头抗拉强度超过380 MPa.钒合金/不锈钢异种金属焊接接头焊缝正反面成形良好,X射线探伤未发现裂纹和气孔缺陷.     

Microstructures and Mechanical Properties of Electron Beam-Welded Titanium-Steel Joints with Vanadium,Nickel, Copper and Silver Filler Metals

Electron beam welding experiments of titanium alloy to stainless steel with V, Ni, Cu and Ag filler metals were carried out. The interfacial microstructures of the joints were examined by optical microscopy, scanning electron microscopy, and x-ray diffraction analysis. Mechanical properties of the joints were evaluated according to tensile strength and microhardness. The results showed that all the filler metals were helpful to restrain the Ti-Fe intermetallics formed in the Ti/Fe joint. The welds with different filler metals were all characterized by solid solution and interfacial intermetallics. And the type of solid solution and interfacial intermetallics were depended on the metallurgical reactions between the filler metals and base metals. The interfacial intermetallics were Fe₂Ti + Ni₃Ti + NiTi₂, TiFe, Ti₂Ag, and Cu₂Ti + CuTi + CuTi₂ in the joints welded with Ni, V, Ag, and Cu filler metals, respectively. The tensile strengths of the joints were primarily determined by the hardness of the interfacial intermetallics. The highest tensile strength was obtained in the joint welded with silver filler metal, which is about 310 MPa.     

钢侧偏束电子束焊接纯铝/Q235异种金属接头试验

采用钢侧偏束电子束焊接方法对铝/钢异种金属接头进行了连接,对接头组织和相组成进行了分析,并对接头抗拉强度进行了了测试.结果表明,钢侧结合良好,焊缝组织均匀,铝侧熔合区存在过渡层,其内有金属间化合物层存在.适当的钢侧偏束量能够提高接头强度,在文中试验范围内,在偏束量为0.5 mm时获得了相对最高的抗拉强度69 MPa.金属间化合层的存在弱化了接头强度,断裂呈脆性特征.     

TA15钛合金与304不锈钢的电子束焊接

对TA15钛合金和304不锈钢的电子束焊接进行了研究,对接头显微组织、相组成和显微硬度进行了分析.结果表明,TA15与304不锈钢电子束焊接性较差,在较小的热应力下即在焊缝内产生大量裂纹.焊缝内生成连续分布的化合相,主要包括TiFe2,TiFe,Cr2Ti等,脆性化合物的产生是裂纹形成的根本原因.焊缝区内显微硬度明显高于母材,且TiFe2的硬度高于TiFe相,贯穿裂纹在TiFe2相富集的区域产生.二者的直接电子束焊接难以实现,需要添加中间层以改善焊缝的冶金条件,改变化合物的种类和分布,从而实现可靠连接.     

旁路分流电弧钎焊钛/钢异种金属接头特性分析

以旁路分流电弧焊方法为技术手段,以S211铜合金为填充钎料,进行钛/钢异种金属电弧钎焊工艺试验. 利用光学显微镜、扫描电镜、万能拉伸试验机等,对钎焊接头的宏观及微观组织、元素分布、抗拉强度进行分析,并利用显微硬度仪分析钎焊接头硬度的变化趋势. 结果表明,采用该方法可获得成形良好的钛/钢异种金属钎焊接头,未见明显的焊接缺陷;硬度测试发现钛/铜界面处的硬度明显升高,这与钛/铜区域易形成Ti-Cu金属间化合物有关;钎焊接头的断裂发生在铜/钛侧,断裂方式属于韧-脆混合断裂,抗拉强度为291.55 MPa,约为铜钎料强度的88%.     

Cu46Zr46Al8非晶合金电子束焊接特性分析

对Cu₄₆Zr₄₆Al₈非晶合金进行了电子束焊接,并分析了接头微观组织转变、显微硬度分布及拉伸性能.结果表明,Cu₄₆Zr₄₆Al₈非晶合金电子束焊接接头熔化区组织大部分仍为非晶态,过冷液相区内发生晶化形成Cu-Zr金属间化合物.焊接接头熔化区与母材硬度相当,过冷液相区硬度值显著降低.接头抗拉强度及韧性相比母材都明显降低,拉伸断裂于过冷液相区内的脆性化合物层,呈现典型的沿晶脆性断裂特征.