中间层对Ni-Cr-W高温合金扩散连接界面组织的影响

为研究新型Ni-Cr-W合金的扩散连接界面组织特征,采用Cu、Ni、Cu/Ni/Cu箔作中间层,在950℃、30 MPa、45 min条件下利用真空扩散连接技术对此合金进行了焊接,并与直接扩散连接形成对比,分析了不同中间层材料对新型Ni基合金扩散连接界面显微组织及元素扩散浓度分布的影响.结果表明:直接扩散连接接头处存在明显的孔洞及二次碳化物M23C6,阻碍了元素的充分扩散,连接界面质量较差;采用Cu箔中间层时,界面连接良好且形成了厚度为1.3μm的反应层;以Ni箔作中间层时,扩散界面连接良好但无明显反应层存在;而以Cu/Ni/Cu作中间层时,Ni-Cr-W/Cu界面上有较薄反应层生成,Cu/Ni界面则形成厚度达9μm的无限固溶体层,对比分析表明,高温合金晶界处M23C6的大量析出严重阻碍了Cu原子的扩散.     

Ni中间层对QBe2.5/钢激光点焊接头力学性能的影响

流量阀的执行机构常应用铍青铜/钢复合元件,本文采用0.05 mm纯Ni作为中间层对QBe2.5铍青铜薄片与20#钢异种金属激光点焊搭接接头力学性能进行优化.通过光学显微镜、拉剪试验、显微硬度计和能谱测试仪对比分析添加Ni与不添加Ni层时焊接接头的成形、力学性能以及元素分布.研究表明:与未加镍层接头相比,加镍中间层的焊缝熔深较小,且基本不出现下塌现象,加镍中间层比未加中间层的接头抗拉剪力提高了61.5%;加入镍中间层后的焊缝中Fe元素含量增加,而Cu元素含量降低,接头韧性提高;加镍中间层的接头焊缝硬度值沿焊点深度方向逐渐增大,而未加镍层的基本不变,且加镍层比未加镍层的接头界面显微硬度值低.镍中间层材料可以显著改善铍青铜/钢异种金属接头焊缝熔合比,提高接头的抗拉剪强度、塑性和韧性     

添加Ni箔中间层的Mg-Al扩散焊接接头界面结构和力学性能

采用扩散焊接工艺,通过添加Ni箔中间层对镁铝异种金属进行焊接。利用无损检测、电子探针、扫描电镜、万能材料试验机研究了Mg/Ni/Al焊接接头界面的组织结构和力学性能。结果表明:Ni箔中间层可以有效阻止界面处Mg,Al元素的相互扩散,接头界面处没有生成Mg-Al金属间化合物。在焊接温度440℃,保温时间90min时,接头抗剪强度达到最大值20.5MPa。Mg/Ni/Al接头由Al,Ni和Mg,Ni的相互扩散形成,接头界面形成Al-Ni过渡区和Mg-Ni过渡区,界面主要物相分别为Al3Ni2,Al3Ni和Mg2Ni,过渡区厚度随焊接温度升高而增加。     

等温时效对SnAgCu/Cu焊接接头显微组织及强度的影响

研究了SnAgCu焊料与铜基的接头在150℃等温时效后,接头界面金属间化合物的形成与转变.用扫描电镜观察在时效过程中焊接接头的显微组织演变.用X射线能谱仪测定了化合物的成分.结果表明,回流焊接时,在焊料和铜基板之间形成了Cu6Sn5化合物层,随着时效时间的增加,Cu6Sn5的晶粒大小逐渐增加,并且形态逐渐从扇贝状依次转变为针状和杆状,最后转变为颗粒状.与此同时,在焊料及Cu6Sn5金属间化合物层之间形成了杆状的Ag3Sn.焊接接头的抗拉强度的测量表明,抗拉强度随着时效时间的增加开始略有增加而后逐渐下降.断口观察发现,随着时效时间的增加,断裂源从焊料内部向Cu6Sn5界面移动.在化合物层界面发生的断裂是由于化合物晶粒粗化和Cu6Sn5化合物层厚度的增加造成的.     

6061铝合金/DP600钢电阻点焊接头特征及力学性能

目的 提升6061-T6铝合金/DP600双相钢电阻点焊接头的力学性能,以满足该焊接结构在汽车工业中的应用。方法 对6061-T6铝合金与DP600双相钢分别进行了直接电阻点焊试验及添加Ni中间层的电阻点焊试验,采用光学显微镜、扫描电子显微镜及能谱仪分析了接头界面宏微观组织、化学成分、元素分布等,此外还采用接头拉剪试验进行了2种接头的力学性能测试,并对接头的断口形貌及断裂模式进行了分析。结果 直接点焊接头熔核界面形成了厚度约为2.5μm的金属间化合物层,主要金属间化合物为靠近铝合金侧的Fe₂Al₅及靠近高强钢侧的Fe₄Al₁₃。直接点焊接头的拉剪载荷为3.1 kN,失效形式为界面断裂,断口呈以脆性为主的混合断裂特征。添加Ni中间层的点焊接头界面形成了Ni₄Al₁₃、Ni₂Al₅金属间化合物,抑制了焊接过程中Al-Fe互扩散并降低了Al-Fe金属间化合物的形成以及硬脆性Al-Fe金属间化合物对接头力学性能的影响,使...     

Ti(C,N)/Ni扩散焊接界面的组织和性能

以铜和铌作为中间夹层,真空扩散焊接Ti(C,N)/Ni,研究温度和时间等主要工艺参数对Ti(C,N)/Ni界面微观组织和性能的影响.结果表明,当扩散焊接的温度低于1273 K时,界面的夹层材料基本保持不变,界面的微观组织为Cu/Nb层状物,铜在镍中有少量扩散;而当扩散焊接的温度为1523K时,界面微观组织在初期为Ni8Nb的金属问化合物 离散析出的CuNi固溶体,到后期变为靠近Ti(C,N)侧为(Ti,Nb)(C,N) NbT(Ni,Ti,Cu)6 NbNia层,靠近Ni侧为NiCu NbNis层.这表明,液态Cu为过渡液相,通过Ni的溶解而形成CuNi过渡液相,加速了Nb在CuNi过渡液相中的溶解.由此产生的NiNbCu过渡液相能浸润Ti(C,N),并在界面处形成少量的(Ti,Nb)(C,N)固溶体合金,从而提高了界面的结合性能,界面剪切强度可达到140 MPa.     

NiCuNbCr焊料Ti_3Al/GH4169合金氩弧焊接头的组织及性能

采用钨极氩弧焊方法,使用自行设计制备的NiCuNbCr合金作为焊料,实现Ti3Al基合金与GH4169高温合金异种材料之间的焊接。采用扫描电镜(SEM)及能谱分析(XEDS)等方法对接头横截面的微观组织进行分析。结果表明:GH4169/焊缝界面以及焊缝均主要由Ni元素的固溶体组成,其中固溶了Cu,Fe,Cr,Nb几种元素;而焊缝/Ti3Al界面分为3层组织,其相组成从Ti3Al母材到焊缝方向依次为:固溶了Ni和Cu元素的Ti2AlNb相、Al(Ni,Cu)2Ti金属间化合物及(Nb,Ti,Mo)固溶体;(Ni,Nb,Cr)及Ni(Cu,Ti)固溶体;Ni的固溶体,固溶元素为Cu,Nb和Cr。接头的平均室温抗拉强度为140.7MPa。拉伸试样断裂于被焊Ti3Al母材表面的扩散反应层,它主要由固溶了Ni和Cu元素的Ti2AlNb相与Al(Ni,Cu)2Ti金属间化合物组成,该界面是Ti3Al/GH4169接头的薄弱环节。     

基于添加铜过渡层的钛钢异种金属真空扩散焊研究

研究了添加铜箔过渡层进行扩散焊接的纯钛TA2和14MnMoVN钢焊接接头的组织和性能。采用OM、扫描电镜、能谱分析和X射线衍射分析对扩散焊接界面的微观组织、元素扩散和组织结构进行分析观察,通过拉伸试验对接头力学性能进行测试。结果表明:通过添加铜过渡层进行扩散焊接可以获得有效连接的钛/钢异种金属复合接头。结合良好的界面可以划分为接头元素扩散过渡区和铜钛结合区。其中钛向铜扩散,少量铁向铜扩散,这是三种元素的综合扩散过渡区。铜钛结合区是铜向钛扩散的区域,主要产生大量的铜钛金属间化合物。接头拉伸强度可以达到299 MPa,断裂位置位于铜钢结合区。     

Ti-61Ni真空钎焊TZM合金接头界面组织与力学性能

目的 研究不同钎焊温度下获得TZM/Ti-61Ni/TZM接头的微观组织演化及力学性能的变化,为获得可靠钎焊接头提供指导.方法 采用电弧熔炼方法制备Ti-61Ni,将以TZM/Ti-61Ni/TZM"三明治"结构装配的试样放入真空炉中进行不同温度(1200～1280℃)下的钎焊连接,利用SEM和EDS等手段分析钎料与母材之间的相互作用,测试接头的力学性能并分析接头断裂行为,研究温度对接头界面组织演化和力学性能的影响.结果 钎缝主要为TiNi相和TiNi3相,钎料中Ti元素向母材扩散形成Mo(s,s)扩散层;钎焊温度升高,钎缝宽度减小,TiNi相减少,钎料对TZM母材的溶蚀加剧;接头的抗剪强度先升高后下降,接头在TZM母材处断裂.结论 采用Ti-61Ni高温钎料实现了TZM合金的可靠连接,接头典型界面组织为TZM/扩散层(Mo(s,s))/TiNi+TiNi3/扩散层(Mo(s,s))/TZM;当钎焊温度为1240℃时,接头的抗剪强度达到最大值,为121 MPa.     

水下搅拌摩擦焊对铝/铜接头组织与性能的影响

目的 采用搅拌摩擦焊,对比分析大气环境和水下环境下铝/铜接头的组织与性能,以期获得力学性能更优异的铝/铜焊接接头。方法 利用搅拌摩擦焊,在焊接速度为40 mm/min、旋转速度为1 000 r/min的条件下,分别在大气环境和水下环境下对厚度为9 mm的6061铝合金板和T2纯铜板进行焊接。然后,对铝/铜界面、焊核区进行扫描电镜及能谱分析,并对铝/铜界面及焊核区进行物相分析,确定产物相组成。最后,对铝/铜试样进行拉伸及硬度检测。结果 铝/铜接头均无裂纹、气孔等缺陷。铜颗粒弥散分布在焊核区,铝/铜界面形成金属间化合物层。水下搅拌摩擦焊下界面元素扩散距离明显变短,且金属间化合物厚度更薄。铝/铜接头的金属间化合物为AlCu和Al4Cu9。大气环境焊接下接头的抗拉强度为130.6 MPa,断裂方式为脆性断裂;水下焊接下接头的抗拉强度为199.5 MPa,断裂方式为韧性断裂。水下环境下的接头硬度值更高,其中热影响区的硬度最低值约为65HV。结论 水下搅拌摩擦焊铝/铜接头无裂纹、气孔等缺陷。组织上,水下搅拌摩擦焊的铝/铜接头界面元素扩散距离更短,硬脆的金属间化合物更少;性能上,水下搅拌摩擦焊的铝/铜接头强度更高,抗拉强度达到199.5 MPa,达到母材的74.4%。     

Effect of Ni interlayer on strength and microstructure of diffusion-bonded Mo/Cu joints

Mo and Cu were bonded successfully by means of diffusion bonding using a Ni interlayer. The tensile strength of the joint increases firstly and then decreases with the bonding temperature or holding time increases. Compared with 79 MPa which was the maximum value of Mo/Cu joint, the maximum tensile strength of joint with Ni interlayer was 97 MPa. The interfacial structure of the joints was studied by SEM, EPMA, EDS and XRD, the results showed that the different atoms diffused to each other in the bonding process and no intermetallic compound appeared. MoNi and NiCu solid solutions formed in the joint. The fracture of the joint had taken place in the Mo/Ni interface rather than in the Ni/Cu interface and the fracture way of the joints was brittle fracture.     

三价铈离子掺杂氯化钾的光致发光性能

采用水热蒸发法制备了KCl∶Ce3+荧光粉。测量并分析了材料在室温下的真空紫外激发光谱及相应的发射光谱。结果表明激发谱显示6个峰,峰位分别为149、194、206、219、233和251nm。其中149nm的激发峰是基质吸收引起的;194、206、219、233和251nm是Ce3+离子的4f→5d跃迁引起的。发射峰显示双峰结构,峰位分别是311和326nm。此峰对应于Ce3+离子的5d→4f(2F5/2,2F7/2)跃迁。     

Reverse polarity effect and cross-solder interaction in Cu/Sn–9Zn/Ni interconnect during liquid–solid electromigration

The diffusion behavior of Zn atoms and Cu–Ni cross-solder interaction in Cu/Sn–9Zn/Ni interconnects during liquid–solid electromigration were investigated under a current density of 5.0 × 10³ A/cm² at 230 °C. Under the combined effect of chemical potential gradient and electron wind, Zn atoms with positive effective charge number would directionally diffuse toward the Cu interface under both flowing directions of electrons. When electrons flowed from Cu substrate to Ni substrate, EM significantly enhanced the diffusion of Cu atoms to the opposite Ni interface, resulting in the formation of interfacial Cu₅Zn₈; while no Ni atoms diffused to the opposite Cu interface. When electrons flowed from Ni substrate to Cu substrate, only a small amount of Cu atoms diffused to the opposite Ni interface, resulting in the formation of a thin interfacial (NiCu)₃(SnZn)₄ (containing 3 wt% Cu); EM significantly accelerated the diffusion of Ni atoms to the Cu interface, resulting in the formation of a large amount of (NiCu)₃(SnZn)₄ at the Cu interface. Even under downwind diffusion, no apparent consumption of Cu substrate was observed due to the formation of a thick and dense Cu₅Zn₈ layer at the Cu interface. It is more damaging with electrons flowing from Ni to Cu than that from Cu to Ni.     

Study on cold metal transfer welding–brazing of titanium to copper

3 mm Pure titanium TA2 was joined to 3 mm pure copper T2 by Cold Metal Transfer (CMT) welding–brazing process in the form of butt joint with a 1.2 mm diameter ERCuNiAl copper wire. The welding–brazing joint between Ti and Cu base metals is composed of Cu–Cu welding joint and Cu–Ti brazing joint. Cu–Cu welding joint can be formed between the Cu weld metal and the Cu groove surface, and the Cu–Ti brazing interface can be formed between Cu weld metal and Ti groove surface. The microstructure and the intermetallic compounds distribution were observed and analyzed in details. Interfacial reaction layers of brazing joint were composed of Ti₂Cu, TiCu and AlCu₂Ti. Furthermore, crystallization behavior of welding joint and bonding mechanism of brazing interfacial reaction were also discussed. The effects of wire feed speed and groove angle on the joint features and mechanical properties of the joints were investigated. Three different fracture modes were observed: at the Cu interface, the Ti interface, and the Cu heat affected zone (HAZ). The joints fractured at the Cu HAZ had higher tensile load than the others. The lower tensile load fractured at the Cu interface or Ti interface was attributed to the weaker bonding degree at the Cu interface or Ti interface.     

Ultrasonic Welding of Ni and Cu Sheets

Ultrasonic metal welding is widely used in various fields due to its ability to weld a variety of materials such as new materials and sheet structures. In this study, a special horn with four-point tips was developed for the ultrasonic welding of Ni and Cu sheets used as electrode materials of the secondary cell. The effects of welding parameters (welding time, clamping pressure, and vibrational amplitude) on weldability were investigated using the developed horn. The weldability of Ni/Cu sheet was assessed via the tensile test, scanning electron microscope observation, and EDX-ray analysis of the weld zone. Experimental results showed that the optimal welding parameters were a welding time of 0.25 s, pressure of 0.20 MPa, and vibrational amplitude of 80%, with a welding strength of 87.45 N under these conditions. It was also confirmed that solid-state diffusion by vibrational and frictional heat was clearly generated at the welding interface under good welding conditions.     

Interface analysis of embedded chip resistor device package and its effect on drop shock reliability

In this study, the drop reliability of an embedded passive package is investigated under JESD22-B111 condition. Chip resistors were buried in a PCB board, and it was electrically interconnected by electroless and electrolytic copper plating on a tin pad of a chip resistor without intermetallic phase. However tin, nickel, and copper formed a complex intermetallic phase, such as (Cu, Ni)6Sn5, (Cu, Ni)3Sn, and (Ni, Cu)3Sn2, at the via interface and via wall after reflow and aging. Since the amount of the tin layer was small compared with the solder joint, excessive intermetallic layer growth was not observed during thermal aging. Drop failures are always initiated at the IMC interface, and as aging time increases Cu-Sn-Ni IMC phases are transformed continuously due to Cu diffusion. We studied the intermetallic formation of the Cu via interface and simulated the stress distribution of drop shock by using material properties and board structure of embedded passive boards. The drop simulation was conducted according to the JEDEC standard. It was revealed that the crack starting point related to failure fracture changed due to intermetallic phase transformation along the via interface, and the position where failure occurs experimentally agrees well with our simulation results.     

Wetting Behavior and Interfacial Reactions in (Sn-9Zn)-2Cu/Ni Joints during Soldering and Isothermal Aging

The wetting property of (Sn-9Zn)-2Cu (wt pct) on Ni substrate and the evolution of interfacial microstructure in (Sn-9Zn)-2Cu/Ni joints during soldering as well as isothermal aging were studied.The wetting ability of eutectic Sn-9Zn solder on Ni substrate was markedly improved by adding 2 wt pct Cu into this solder alloy.Plate-like Cu5Zn8 intermetallic compounds (IMCs) were detected in (Sn-9Zn)-2Cu solder matrix.A continuous Ni5Zn21 IMC layer was formed at (Sn-9Zn)-2Cu/Ni interface after soldering.This IMC layer kept its type and integrality even after aging at 170℃ for up to 1000 h.At the early aging stage (before 500 h), the IMC layer grew fast and its thickness followed a linear relationship with the square root of aging time.Thereafter,however, the thickness increased very slowly with longer aging time.When the joints were aged for 1000 h,a new IMC phase, (Cu,Ni)5Zn8, was found in the matrix near the interface.The formation of (Cu,Ni)5Zn8phase can be attributed to the diffusion of Ni atoms into the solder matrix from the substrate.     

Al-Cu双金属复合结构的扩散连接试验研究

应用扩散连方法进行了Al-Cu双金属复合结构的试验研究，比较了不同的焊接工艺，材料组合以及母材状态情况Al合金与Cu的连接性，观察了接头区域的微观组织结构，研究表明，固相扩散连接是一种适用于异种材料连接的有效方法，通过在连接区域形成Al-Cu金属间化合物，达到Al和Cu的有效连接，材料组合，母材原始状态以及连接工艺参数对Al合金与Cu的扩散连接存在着明显的影响。表面镀Ni工艺不但能够有效阻止Al和Cu之间形成脆性相，而且Al和Ni之间形成了良好的扩散连接，改善了接头性能。