Ni-Al超声楔焊键合分离界面的结构特性及演变规律

设计了一系列的粗铝线楔焊键合试验，用扫描电镜测试分离的楔焊界面，通过采集驱动电信号分析了压电陶瓷输入功率特性。结果表明，Ni—Al超声键合的界面模式形如脊皱圆环，中心和外边是未结合的摩擦痕，脊皱构成强度，相同参数条件下，一焊脊皱峰和转化的超声能大于二焊；其它参数不变的条件下，随压力的增加，键合面尺寸增大，圆环的短轴延伸为长轴，随时间的增加，脊皱扩展为完整的圆环，脊皱尺寸向中央扩大，随功率的增加，摩擦痕和脊皱加剧，且这些参数存在一个最佳范围。     

Characterization of diffusion-bonded joint between Al and Mg using a Ni interlayer

Aluminum and magnesium were joined through diffusion bonding using Ni interlayer. The microstructure and mechanical performance of the Al/Ni/Mg joints at different temperatures was investigated by means of scanning electron microscope(SEM), electro-probe microanalyzer(EPMA), X-ray diffraction(XRD), Vickers hardness testing, and shear testing. The results show that the addition of Ni interlayer eliminates the formation of Mg–Al intermetallic compounds and improves the bonding strength of the Al/Mg joints. The Al/Ni/Mg joints are formed by the diffusion of Al, Ni and Mg, Ni. The microstructure at the joint interface from Al side to Mg side is Al substrate/Al–Ni reaction layer/Ni interlayer/Mg–Ni reaction layer/Mg substrate multilayer structure. The microhardness of the Mg–Ni reaction layer has the largest value of HV 255.0 owing to the existence of Mg_2Ni phase.With the increase of bonding temperature, the shear strength of the joints increases firstly and then decreases.The Al/Ni/Mg joint bonds at 713 K for 90 min, exhibiting the maximum shear strength of 20.5 MPa, which is greater than that of bonding joint bonded directly or with Ag interlayer. The fracture of the joints takes place at the Mg–Ni interface rather than the Al–Ni interface, and the fracture way of the joints is brittle fracture.     

镍作中间层脉冲加压扩散连接钛合金与不锈钢

采用纳米Ni粉、纳米Ni镀层、Ni箔作中间过渡层,对TA17近。型钛合金与0Cr18Ni9Ti不锈钢进行了脉冲加压扩散连接,接头抗拉强度分别达到了175,212,334MPa。在金相显微镜下,对拉伸断口形貌进行了观察和分析;利用扫描电镜（SEM）、能谱仪（EDS）、X射线衍射分析（XRD）测定了连接接头各区域内的微区成分和物相。结果表明,纳米Ni粉致密度不够高,纳米Ni镀层质量不够高,在很大程度上限制了接头强度的提高;Ni箔中间层的存在成功地阻止了Fe与Ti之间的互扩散,避免了形成脆而硬的Fe—Ti系金属间化合物。     

Solid-State Diffusion Bonding of Nb_(SS)/Nb_5Si_3 Composite Using Ni/Al and Ti/Al Nanolayers

Diffusion bonding of refractory Nb–Si-based alloy was performed with Ni/Al and Ti/Al nanolayers under the condition of 1473 K/30 MPa/60 min. The Nb_(SS)/Nb_5Si_3 in situ composite with the nominal composition of Nb–22 Ti–16 Si–3 Cr–3 Al–2 Hf was used as the parent material. The joint microstructures were examined by using a scanning electron microscope equipped with an X-ray energy dispersive spectrometer. Shear test was conducted for the bonded joints at room temperature.Within the joint bonded with Ni/Al multilayer, element diffusion occurred between the base metal and the nanolayer, with the reaction products of AlNb_2 + Ni_3 Al, NiAl and AlNi_2 Ti phases. The average shear strength was 182 MPa. While using Ti/Al multilayer, the interface mainly consisted of TiAl,(Ti,Nb)Al and(Ti,Nb)_2 Al phases, and the corresponding joints exhibited an increased strength of 228 MPa. In this case, the fracture mainly took place in the TiAl phase and presented a typical brittle characteristic.     

Characterization of the interfacial-microstructure evolution and void shrinkage of Ti-22Al-25Nb orthorhombic alloy with different surface roughness during diffusion bonding

Ti-22Al-25Nb alloy specimens with different surface roughness were joined, through diffusion bonding at 975 °C at 12.5 MPa. The interfacial-microstructure evolution during this process was characterized via scanning electron microscopy combined with electron probe microanalysis and electron backscatter diffraction analysis. Further, the interfacial void-shrinkage mechanism and the quality of the bonded joints were determined through atomic force microscopy, which revealed the three-dimensional morphologies of the surfaces, and shear strength testing of the joints. The results revealed that fine equiaxed α₂ grains are precipitated in the bonding interface of specimens with ground surfaces. These interfacial α₂ grains were formed via phase transformation and recrystallization processes, which were triggered by asperity deformation at the contact plane and unavoidable oxygen contamination. Two types of fracture occurred during the shear strength tests, where the bonds generated from (i) polished surfaces failed predominantly along the bond line, and (ii) ground surfaces failed predominantly in the base material away from the bond line. This indicated that the mechanism controlling the void-shrinkage process associated with the contact between two rough surfaces during diffusion bonding varied with the surface roughness: the void-shrinkage process of specimens with (i) polished surfaces is controlled by diffusion, and (ii) ground surfaces was controlled by both diffusion and plastic deformation.     

AZ31B/TA2爆炸焊接复合板界面结合机制及力学性能的研究

镁合金AZ31B和纯钛TA2通过爆炸焊接成功的方法成功实现了连接。采用光学显微镜(OM)、扫描电镜(SEM)、以及电子能谱(EDS)等测试手段对结合界面的微区结构、元素分布进行了分析。研究了在不同温度热处理后AZ31B和TA2界面之间元素的扩散情况。同时结合显微硬度实验、冲击试验、拉伸试验研究了复合板的力学性能。并对复合板的结合机制进行了一定的探讨。研究结果表明：平直和波浪状结合形貌并存于结合界面。在热处理温度为450?C和490?C、保温时间为4h和8h时,界面元素扩散明显。由于两侧金属发生塑性变形导致界面硬度升高。复合板的各种力学性能均较基板AZ31B镁合金得到了一定程度的提高。     

焊接能量对Mg/Ti超声波焊接接头微观组织与力学性能的影响

采用超声波焊接技术对Mg/Ti异种金属进行了焊接,研究了不同焊接能量对接头界面峰值温度、界面形貌、界面原子扩散程度以及力学性能的影响规律。研究发现:Mg/Ti超声波焊接接头整体界面较平直,局部界面有较小起伏,未发现裂纹、未熔合等缺陷,也未看到明显的反应层;随着焊接能量的增大,界面峰值温度升高,原子扩散层厚度增大,连接区面积逐渐增大,接头力学性能得到提高,而能量达到2000J时镁侧母材出现裂纹;接头断裂模式分为界面断裂和纽扣断裂,界面断裂时断裂发生在镁侧扩散层区域和镁侧非扩散层区域。扫描电子显微镜和X射线衍射仪分析表明,Mg/Ti连接界面区域无明显的金属间化合物生成。     

Al2O3弥散铜/纯铜扩散焊工艺

采用真空扩散连接工艺,对Al2O3弥散强化铜/纯铜的连接进行了试验研究.用扫描电镜分析了Al2O3弥散强化铜/纯铜扩散界面组织结构,研究了工艺参数对界面结合状态和组织结构的影响.通过正交试验得出各因素对接头抗拉强度的影响大小依次为:扩散温度＞压力＞保温时间.正交试验结果表明:焊接温度为550℃,保温时间为3h,压力为25 MPa时,可获得组织均匀致密、界面连续的Al2弥散铜/纯铜扩散焊接头,且接头抗拉强度高达116.9 MPa.     

钨铜/铍青铜异质钎焊界面组织与性能

采用BAg56CuZnSn,BAg50ZnCdCuNi和BAg49ZnCuMnNi银钎料实施了钨铜合金/铍青铜异质材料接头的感应钎焊连接,研究了其钎焊界面组织与力学性能.结果表明,3种银钎料均能获得完好界面钎焊接头,钎料与钨铜和铍青铜形成较好冶金结合.钎料与铍青铜界面冶金结合充分,形成明显互扩散区.钎料与钨铜钎焊界面清晰,且钎料向钨铜近界面区域形成明显扩散渗入现象.强度测试表明,BAg49ZnCuMnNi钎焊接头强度最高,达到250 MPa,接头断裂均发生在钨铜侧钎焊界面.分析表明,钎料向钨铜渗入明显促进界面结合,钎料中添加镍,由于镍与钨的扩散互溶进一步提高界面冶金结合,Mn元素添加明显细化钎缝晶粒,接头强度显著提升.     

加热时间对钛合金热自压连接及接头组织性能影响

对不同加热时间下获得的钛合金刚性拘束热自压连接接头进行了连接界面光学显微镜观察,背散射电子衍射组织分析和接头拉伸力学性能测试,分析了加热时间对连接接头界面缺陷、组织和力学性能的影响。同时,利用热弹塑性有限元模型分析了连接中热应力应变演变过程,阐明了加热时间对连接接头界面焊合质量、组织和力学性能影响的原因。结果表明：加热峰值温度相当的情况下,加热时间增加,界面金属高温存在时间和受压应力作用时间以及横向压缩塑性变形增加,促进界面两侧原子扩散,界面未焊合缺陷减少,接头综合力学性能提高。加热时间至300s以上时,可以获得界面焊合质量好,组织均匀,综合力学性能优异的固相连接接头。     

氢对多孔Ti6Al4V合金扩散连接质量的影响

文章通过采用Gleeble1500热模拟机进行真空扩散连接试验,研究了氢对多孔Ti6Al4V合金扩散连接质量的影响,并应用光学显微镜、扫描电镜(Scanning electron microscope,SEM)及电子万能试验机对界面孔洞弥合率、界面组织形貌、抗弯强度和断口形貌进行分析。结果表明,真空扩散连接后的孔洞弥合率随着原始氢含量的增加而升高,但升高的趋势逐渐平缓;扩散连接后,原始氢含量较低的试样室温组织为α+片状(α+β),原始氢含量高的试样室温组织为条状α+等轴状(α+β);室温下,在一定的氢含量范围内,氢元素在多孔合金中以间隙固溶和氢化物状态存在,均起到了强化作用,使扩散连接后材料抗弯强度增加;随着剩余氢含量的增加,断口由韧性沿晶断裂逐渐转变为脆性沿晶断裂和解理型穿晶断裂两种断裂方式的混合,并且随着氢含量增加,穿晶解理断裂特征增多。     

轧制压下率对Cu/Al层状复合材料界面扩散层生长的影响

采用金相显微镜、SEM及EDS等分析手段对Cu/Al冷轧复合界面结合机理进行研究,建立扩散退火阶段不同轧制压下率时的扩散层生长动力学方程,并探讨了不同压下率对界面扩散层生长的影响。结果表明,轧制复合阶段界面形成激活中心数量随压下率的升高而增加,当压下率为75%时达到峰值。另外,压下率在退火温度较高时对扩散层生长影响显著。     

压力对FGH96/GH4169高温合金惯性摩擦焊接头性能的影响

在惯性摩擦焊机上对FGH96/GH4169高温合金进行了焊接,焊后利用光学显微镜、扫描电镜以及拉伸试验机等设备分析了接头的微观组织形貌、显微硬度、拉伸性能及断口形貌. 结果表明,摩擦焊近界面处最高温度接近1 100 ℃,界面处温度超过强化相固溶温度. 焊缝区组织为细小的等轴晶粒,晶粒尺寸远小于母材,热力影响区发生了拉伸变形. 焊后接头热力影响区处的强化相部分重溶,接头界面细晶区的强化相完全重溶. 随压力增大,Co原子的扩散距离增加,接头室温抗拉强度和高温抗拉强度有所升高,断裂位置位于GH4169侧热力影响区,断裂形式为韧性断裂.     

铝/钢无匙孔搅拌摩擦点焊焊接性分析

采用自行设计的无匙孔搅拌摩擦点焊方法对6061铝合金和DP600镀锌钢进行点焊(钢上铝下),利用扫描电镜、能谱仪及拉伸试验对接头的微观组织和力学性能进行研究.结果表明,搅拌头旋转频率为1200 r/min、预热时间为6 s和搅拌针长度为3.2 mm时,接头抗剪载荷可达11.2 kN.接头表面平整美观无匙孔;接头由搅拌区和扩散区组成,搅拌区内钢以弯钩状分布嵌入铝基体,形成牢固的机械连接;扩散区内铝和钢依靠界面上的金属间化合物连接,连接方式为冶金结合.接头断裂位置为扩散区化合物层与铝基体界面处,断口呈河流状的解理台阶,属于脆性断裂.     

AZ31B/Q235激光诱导电弧填丝焊连接界面分析

利用激光诱导TIG电弧复合热源,通过添加AZ61镁合金焊丝,开展了1.6 mm厚AZ31B镁合金和1.0 mm厚Q235低碳钢板材对接焊研究.分别采用扫描电镜、电子探针、万能拉伸试验机、金相显微镜等仪器进行分析测试.结果表明,采用激光诱导电弧双面填丝焊接工艺,能够获得成形美观、连续的焊缝,焊接接头平均抗拉载荷为3.13 kN.连接界面包括两部分:镁与钢的对接界面为熔化焊接,主要以界面元素扩散为主;远离对接面的接头上下界面为镁合金在钢基体的润湿铺展连接.焊接接头断裂路径表明,连接界面发生的元素扩散是实现镁合金与钢高性能连接的关键.     

Impulse pressuring diffusion bonding of titanium to 304 stainless steel using pure Ni interlayer

In the present study,impulse pressuring diffusion bonding technology(IPDB)was utilized between commercially pure titanium and 304 stainless steel(SS)using pure nickel(Ni)as interlayer metal.The interfacial microstructures of the bonded joints were investigated by scanning electron microscopy(SEM)and energy dispersive spectroscope(EDS)analyses.It is found that with the aid of the Ni interlayer,the interdiffusion and reaction between Ti and SS can be effectively restricted and robust joints can be obtained.Intermetallic compounds(IMCs)including Ti_2Ni,Ti Ni,and TiNi_3 are detected at the Ti/Ni interface;however,only Ni–Fe solid solution is found at the Ni/SS interface.The maximum tensile strength of 358 MPa is obtained by IPDB for 90 s and the fracture takes place along the Ti_2Ni and Ti Ni phase upon tensile loading.The existence of cleavage pattern on the fracture surface indicates the brittle nature of the joints.     

钛箔/钢爆炸焊接的界面结合性能

为减小钛/钢爆炸焊接钛层的使用量,以低爆速乳化炸药作为焊接炸药,食盐作为传压层,成功实现厚度200 μm TA1钛箔与Q235钢的爆炸焊接.通过金相显微镜、扫描电镜和能谱仪对界面微观形貌进行分析,利用万能试验机对复合板试件进行拉伸、弯曲试验检测其结合性能. 结果表明,钛箔/钢界面呈规则的波形,主要以熔化层结合,具有良好的结合质量.靠近界面金属产生强烈的塑性变形,钢侧晶粒呈流线状.波后的旋涡内包含熔化块,未观测到孔洞、裂隙等缺陷.根据Ti和Fe元素原子比例,熔化块成分主要为FeTi,Fe₂Ti等金属间化合物.三点弯曲和拉伸试件的界面均未出现分离,复合板材界面具有良好的塑性变形能力和结合性能.拉伸试件断口两侧的钛层与钢层存在大小不一的韧窝,主要呈塑性断裂.     

Phase constitution near the interface zone of diffusion bonding for Fe3Al/Q235 dissimilar materials

The characteristics of phase constitution near the interface of Fe₃Al/Q235 diffusion bonding are researched by means of scanning electron microscope, X-ray diffraction and transmission electron microscope, etc. The test results indicated that an obvious diffusion transition zone forms near the Fe₃Al/Q235 interface as a result of vacuum diffusion bonding (heating temperature 1050–1080 °C, holding time 60 min and pressure 9.8 MPa). The maximum value of the Al content in the transition zone was 16.6 wt.% (about 28.5 at.%). The micro-hardness in the diffusion transition zone was HM 200–400. The transition zone consists of Fe₃Al and α-Fe(Al) solid solution. There was no brittle phase of high hardness near the diffusion interface. This is favorable to the enhancing of the toughness of Fe₃Al/Q235 diffusion joint.     

Diffusion bonding of Ti—6Al—4V titanium alloy powder and solid by hot isostatic pressing

The Ti—6Al—4V (TC4) alloy powder and forged solid were diffusion bonded by hot isostatic pressing (HIP) to fabricate a powder—solid part. The microstructure of the powder—solid part was observed by scanning electron microscope (SEM). The microhardness and tensile tests were conducted to investigate the mechanical properties. The results showed that the powder compact was near-fully dense, and the powder/solid interface was tight and complete. The microhardness of the interface was higher than that of the powder compact and solid. The fractures of all powder—solid tensile specimens were on the solid side rather than at the interface, which indicated that a good interfacial strength was obtained. The tensile strength and elongation of the powder compact were higher than those of the solid. It is concluded that the HIP process can successfully fabricate high-quality Ti—6Al—4V powder—solid parts, which provides a novel near net shape technology for titanium alloys.     

氧化铝基复合陶瓷-金属钎焊界面的热应力

用Ag-Cu-Ti钎料钎焊SiCw／Al2O3复合陶瓷和金属时，陶瓷与钎料发生化学反应，在陶瓷表面形成由TiO、TiC等物相组成的反应层。采用有限元法，对SiCw／Al2O3复合陶瓷／反应层界面的热应力进行了计算。结果表明，复合陶瓷／反应层界面的残余应力变化急剧，最大拉应力位于晶须、基体和反应层交界处；晶须内部及其表面存在较高的双向压应力，Al2O3基体主要承受垂直于界面的拉应力；SiC晶须／反应层界面及其附近的反应产物TiC内具有较高的平行于界面的拉应力，当连接界面承受剪力作用时，SiC晶须／反应层界面和TiC处极易破坏。借助TEM和SEM观察了复合陶瓷／反应层界面区的精细结构和剪切断口形貌，并利用计算结果对观察到的现象进行了分析。