Study on interfacial structure and strength of Si3 N4/Ti/Cu/Ti/Si3 N4 PTLP bonding

Partial transient liquid-phase bonding (PTLP bonding) of Si3N4 ceramic with Ti/Cu/Ti multi-interlayer is performed with changing the thickness of Ti foil. The influence of Ti foil thickness on interface structure and joint strength was discussed. The joint interface structures are investigated by scanning electron microscope (SEM) and energy dispersion spectroscopy(EDS). The results show that the maximum joint strength of 210 MPa is obtained at room temperature in the experiments. When joining temperature and time are not changed and the process of isothermal solidification is sufficient,interface structure, reaction layer thickness and isothermal solidification thickness change with the thickness of Ti foil.     

Ti箔厚度对Si3N4/Ti/Cu/Ti/Si3N4部分瞬间液相连接界面结构及强度的影响

采用Ti／Cu／Ti中间层在l273K、180min的条件下，改变Ti箔厚度进行Si3N4陶瓷的部分瞬间液相(PTLP)连接，讨论Ti箔厚度对界面结构及连接接头强度的影响，用扫描电镜、电子探针对连接界面区域进行了分析。结果表明，在试验范围内，Ti箔厚度为10μm时Si3N4／Ti／Cu／Ti／Si3N4接头的室温强度最高，为210MPa。PTLP连接时，当连接温度和时间不变，且连接时间能保证等温凝固过程充分进行的条件下，Si3N4／Ti/Cu／Ti／Si3N4连接界面结构、反应层厚度、等温凝固层厚度随着Ti箔厚度改变而改变。     

Si_3N_4/Ti/Ni/Ti/Si_3N_4部分瞬间液相连接接头的强度与断裂

在温度为１２７３ ～１４２３ Ｋ、时间为０ ．９ ～７ ．２ ｋｓ 和０ ．１ ＭＰａ 压应力的条件下进行了Ｓｉ３Ｎ４／Ｔｉ／Ｎｉ／Ｔｉ／Ｓｉ３Ｎ４ 的部分瞬间液相连接, 结合ＳＥＭ, ＥＤＳ 和ＸＲＤ 测试结果, 分析了连接温度和时间对接头常温四点弯曲强度和断裂方式的影响。通过用反应层厚度来表征界面强度, 用σＲｅｓθｍａｘ 来评价近界面陶瓷断裂, 用σＲｅｓθ＝ ０ 来评价界面断裂, 建立了界面强度、陶瓷强度和残余应力与接头强度和三种断裂类型的关系模型。     

Interfacial reactions and diffusion path in partial transient liquid-phase bonding of Si_3N_4/Ti/Ni/Ti/Si_3N_4

1INTRODUCTIONPartialtransientliquid-phasebonding(PTLP),whichhastheadvantagesofbothbrazingandsolid-statediffusionbonding,isanewtechnologyusedforceramicjoining['~'].Recently,theauthorshavebeenstudyingthepartialtransientliquid-phasebondingofSi,N'/Ti/Ni/Ti/SisN'withtheemphasesonthemi-grationbehavi0roftheinterfaceandtheselectionofthebondingparameters[#1.Theinterfacialre-actionsbetweenmetalsandceramicsandthein-terfacestructuresareboththekeyfact0rswhichdeterminetheinterfacialstrength[','J.A…     

Si3N4/Ti/Cu/Ni/Cu/Ti/Si3N4二次部分瞬间液相连接强度

采用Ti/Cu／Ni中间层对Si3N4陶瓷进行二次部分瞬间液相(PTLP)连接，研究连接工艺参数对Si3N4／Ti/Cu／Ni连接强度的影响，同时研究了连接强度随试验温度的变化规律。结果表明，在该试验条件下，室温连接强度随着二次连接温度的提高和二次保温时间的延长而提高，改变连接工艺参数对Si3N4／Ti/Cu／Ni二次PTLP连接界面反应层厚度无明显影响；连接强度在试验温度400℃时达到最大，随后随试验温度升高，连接强度降低，但在800℃前，其高温强度具有很好的稳定性。     

Ti/Cu/Ti部分瞬间液相连接Si_3N_4的界面反应和连接强度

用Ti/Cu/Ti多层中间层在 12 73K进行氮化硅陶瓷部分瞬间液相连接 ,实验考察了保温时间对连接强度的影响。用SEM ,EPMA和XRD对连接界面进行微观分析 ,并用扩散路径理论 ,研究了界面反应产物的形成过程。结果表明 :在连接过程中 ,Cu与Ti相互扩散 ,形成Ti活度较高的液相 ,并与氮化硅发生反应 ,在界面形成Si3N4 /TiN/Ti5Si3 Ti5Si4 TiSi2 /TiSi2 Cu3Ti2 (Si) /Cu的梯度层。保温时间主要是通过影响接头反应层厚度和残余热应力大小而影响接头的连接强度     

Effect of bonding parameters on microstructure and properties of Si_3N_4/Si_3N_4 joint brazed by Cu-Zn-Ti filler alloy

1INTRODUCTION Si3N4ceramichashighthermalandwearingresistanceandisapromisingmaterialforhightem peratureapplications.However,itisdifficultto manufacturetheSi3N4ceramicworkpieceswithla gerdimensionsandcomplicatedshapesduetoitspoorworkabilityandlowductility.Inrecent20years,manystudieshavebeenfocusedonthetech niquesofceramicjoining,becausethejoiningtech niquescanbeusednotonlyforlow costandhigh reliabilitymanufacturingofceramicpartswith complicatedshapesbutalsoforrepairingofthece ramicpartsinw…     

Formation mechanism of the porous zone at the bonded Si3 N4/Ni interface

Diffusion bonding of Si3N4 ceramic to itself was performed using Ni interlayer. A flat Si3N4/Ni interface was found at a lower temperature （ 1 273 K）. Whereas at a higher temperature （ 1 473 K）, a porous zone located at the Si3N4/Ni interface and some petal-like Ni3 Si compounds precipitated in the Ni interlayer were observed. The formation mechanism of the porous zone was investigated based on a fracture analysis. An additional stress （O＇add ） generated at the Si3NJNi interface played an important role in the formation of the porous zone, which was resulted from the aggregation of nitrogen during the bonding process. A calculation equation of the O＇aaj was derived to analyze its effects. The results indicated that %~ was directly in dependent with diffusion bonding temperature and dwell time.     

V-4Cr-4Ti/Ti扩散连接接头的界面结构及力学性能研究

利用锻造加工进行了V-4Cr-4Ti/Ti两种材料的扩散连接,并通过OM,SEM,EDS,剪切实验等手段分析和研究了扩散接头的界面结构及其接合强度。微观结构分析表明,扩散接头的总宽度约为100 μm,并分为明显的Ⅰ、Ⅱ两部分：Ti基体侧的Ⅰ区较宽,由致密的针状组织组成;V-4Cr-4Ti合金一侧的Ⅱ区宽度约为Ⅰ区的一半,该区平滑无缺陷,未看到孔洞和裂纹等缺陷的存在。根据材料基体和扩散接头处的硬度分布规律,可以将它们进一步分为A-F六个区域,其中C区的硬度最高,其与钛基体交界区域的最大硬度高达332 HV,远高于基体材料的硬度（钛基体的平均硬度为190 HV,钒合金基体为258 HV）,而E区的硬度较低,最低仅为182 HV。剪切实验结果表明,扩散接头的剪切强度大于165.2 MPa,且断裂发生在靠近扩散接头的钛基边界区域,这很可能是因为金属钛在冷却过程中发生相变导致局部应力集中所造成的。     

热压TiC／Ti／Si／Al合成Ti3SiC2材料的研究

研究了向原料粉中掺加Al粉对合成高纯致密Ti3SiC2材料的影响。实验表明以2TiC／1Ti／1Si／0．2Al为起始原料组成，采用热压工艺在1200℃～1400℃的温度范围内，可以制备得到密度达到理论密度98％以上的高纯致密Ti3SiC2块体材料。由XRD数据计算得到的晶格参数与文献中的值接近。通过SEM和EPMA分析得知Ti3SiC2晶粒呈板状结晶形貌，且发育良好，晶粒在平面内的尺寸分别为3μm～8μm和4μm～10μm。     

用Al-Ti和Al-Zr合金在大气中连接Si3N4陶瓷

用Al-Ti和Al-Zr合金成功地在大气中连接了Si3N4陶瓷,结果表明,适当加压能防止Al-Ti和Al-Zr合金的氧化;连接时间、连接温度和合金中的Ti、Zr含量明显影响接头强度;用Al-Ti和Al-Zr合金连接Si3N4陶瓷时,Al和Ti或Al和Zr同时与Si3N4陶瓷反应形成界面反应层,强化了接头。     

Ti/Cu/Ti复合中间层扩散连接TiC-Al2O3/W18Cr4V接头组织分析

通过添加Ti/Cu/Ti复合中间层,控制加热温度1 130 ℃,保温1 h,连接压力15 MPa,实现陶瓷基复合材料TiC-Al2O3 与高速钢W18Cr4V的真空扩散连接,TiC-Al2O3/W18Cr4V接头抗剪强度达103 MPa.采用扫描电镜、X射线衍射、电子探针等测试方法分析了TiC-Al2O3/W18Cr4V扩散连接接头的微观组织结构和显微硬度分布.结果表明,Ti/Cu/Ti复合中间层与两侧基体TiC-Al2O3和W18Cr4V发生扩散结合,形成均匀致密、宽度为90 μm的扩散过渡区,过渡区显微硬度从3 400 HM逐渐降低到1 000 HM,形成的相结构主要有Ti3Al, CuTi2, Cu和TiC.     

Microstructure of Si3N4/Si3N4 joint brazed using Cu-Pd-Ti alloy filler

Microstructure of the Si3 N4/Si3 N4 joint brazed using an active filler of Cu-Pd-Ti alloy was analyzed by means of EPMA and XRD. The results indicate that a perfect Si3 N4/Si3 N4 joint is obtained by using an active filler of Cu76.5Pd8.5Ti15 alloy with brazing temperature, pressure and holding time of 1 373 - 1 473 K, 2× 10-3 MPa and 1.8 ks, respectively. The filler alloy in the joint is a Cu-Pd solution containing reactant of TiN, PdTiSi and Pd2Si.The interface between the filler alloy and Si3 N4 ceramic is composed of TiN reactant.     

Ti2Ni3Si/NiTi金属间化合物合金在H2SO4溶液中的腐蚀行为

利用激光熔炼材料制备技术,制得了由三元金属硅化物Ti2Ni3Si初生枝晶和枝晶间Ti2Ni3Si/Ti共晶组成的金属间化合物耐磨耐蚀合金;采用极化曲线、塔菲尔图(Tafel Plot)和交流阻抗(EIS)等技术,研究了合金在1 mol/L H2SO4溶液中的电化学腐蚀行为以及Ti含量对合金组织与耐蚀性的影响.结果表明:由于表面形成的稳定钝化膜及Ti2Ni3Si和NiTi的高化学稳定性,使合金在1 mol/L H2SO4溶液中具有优异的耐蚀性,且随着Ti含量的升高,合金的耐蚀性略有提高.     

钛/铝/钛层状复合材料的爆炸复合制备及后续热压处理研究

本文以纯钛板与纯铝板为原料,通过爆炸复合法制备钛/铝/钛层状复合材料,之后采用热处理以及热压工艺对钛/铝/钛层状复合材料进行进一步处理。研究结果表明：复合板界面主要由波状界面和平直状界面构成,铝元素与钛元素在界面上发生了互扩散,界面结合性能优良,可以承受后续较大的二次塑性变形;热处理后的复合板界面发生明显扩散,在热处理25 h后热压2.5 h后铝层完全反应,扩散反应层主要由TiAl₃相以及Ti₂Al₅相构成。     

DIFFUSION BONDING OF TiAl TO Ti AND TC4 ALLOY

1.~nonInrecentyears,considerableinteresthasdevelopedinTiAlbasealloysbecauseOfuniqUepropertiesasattractivematerialsforhigh--temperaturestmcturalaPPlication.TheeffectiveutilizationofTiAlalloysneedstodevelopreliablejoiningtechniqUes,especiallyjoiningtechniquesofTiAltoothermaterials.TheweldabilitiesofTialbasealloyusingfusionweldinghavebeeninvestigatedandweldcrackinghasbeenobserved.ThatsuggeststhatfusionweldingseemstobedifficultforweldingPOorductilematerialsliketitedumaldrini...[IJ.Dissidril…     

Dynamic study in partial transient liquid phase bonding of Si3 N4

Dynamics in partial transient liquid phase bonding ( PTLP bonding) of Si3N4 ceramic with Ti/Cu/Ti multiinterlayer was systematically studied through micro-analysis of joint interfaces. The results show that growth of reaction layer and isothermal solidification procession do at the same time. Growth of reaction layer and moving of isothermal solidification interface obey the parabolic law governed by the diffusion of participating elements during the PTLP bonding. Coordination of the above two dynamics process is done through time and temperature. When reaction layer thickness is suitable and isothermalsol idification process is finished, the high bonding strength at room temperature and high temperature are obtained.     

Boron Solubility in Silicide Ti5Si3

Alloys of the Ti-Si-B system in the Ti₅Si₃ vicinity melted in an arc furnace from pure components were studied after annealing at 1850 °C for 3 h by means of XRD analysis, scanning electron microscopy with electron probe microanalysis (SEM/WDS), and ¹¹B solid state nuclear magnetic resonance (NMR). The phase based on Ti₅Si₃ (D8₈ crystal structure of the Mn₅Si₃ or Hf₅CuSn₃ type), Ti₅Si₄ silicide (Sm₅Ge₄ crystal structure type) and TiB₂ diboride were identified in the alloys. The NMR spectra contained two well-separated narrow peaks (at δ = 9 and δ = 274 ppm; Δν = 18 and Δν = 14 kHz) related to the B atoms located in the crystal lattices of TiB₂ and solid solution based on Ti₅Si₃ respectively, which stand out against a broad peak (δ = 150 ppm, Δν = 120 kHz) from B atoms which lack for a long-range order environment. The ¹¹B spectra were used to determine boron contents in the constituents. The B content of the Ti₅Si₃-based phase determined from the integral intensity of proper narrow peaks is in agreement with SEM/WDS data (both about 5 at.%).     

Zr5Si3及Zr3Ti2Si3弹性性质与热学性质

应用基于密度泛函理论的平面波赝势方法计算16H金属硅化物Zr5Si3及Zr3Ti2Si3的基态晶格参数,得出弹性常数、体弹性模量、弹性模量、剪切模量及泊松比等弹性性质.利用弹性常数计算德拜温度、格林奈森常数,并在德拜-格林奈森模型基础上计算这两种金属硅化物的各向异性热膨胀系数,由此得出Zr5Si3的a、c方向各向异性热膨胀系数(高温时)分别为8×10-6和15×10-6,对Zr3Ti2Si3(高温时)分别为11×10-6和13×10-6,与实验基本相符.根据方向体弹性模量、方向弹性模量及重叠布居数讨论两种材料各向异性热膨胀不同的原因.