工艺参数对Al2O3/TC4合金接头界面组织及力学性能的影响

采用Cu＋B钎料分别在钎焊温度890～970℃,保温时间为10min;钎焊温度为930℃,保温时间0～30min条件下,钎焊A120,陶瓷与TCA合金．利用SEM,EDS和压剪试验研究接头界面组织及力学性能．结果表明,随钎焊温度升高或保温时间的延长,Ti2（Cu,Al）2O层增厚,紧邻其侧生成连续并增厚的Ti2（Cu,Al）,Ti2（Cu,Al）含量增加;Ti＋Ti2（Cu,Al）含量增加,尺寸变大,分布范围逐渐变宽并向TC4合金侧迁移,TCA合金侧过共析组织区变宽．钎焊温度低于950℃时,TiB晶须主要分布在Ti2Cu晶界处的AlCu2Ti上;当钎焊温度高于950℃时,AlCu2Ti相逐渐消失,TiB晶须主要分布于Ti2Cu上．当保温时间为10min,钎焊温度为950℃时,接头最大强度为96MPa;而当钎焊温度为930℃,保温时间为20min时,接头最大强度为83MPa．关键词：Al2O3陶瓷;TC4合金;钎焊参数;界面组织;抗剪强度     

TiAl基合金与Ti合金的真空钎焊

采用Ag-Cu钎料与Ti-Zr-Ni-Cu钎料,对TiAl与Ti合金进行了真空钎焊试验,主要研究了采用两种钎料时的界面反应以及钎焊温度对界面组织及性能的影响.研究发现,采用Ag-Cu钎料时界面结构为:Ti/Ti(Cu,Al)2/TiCux Ag(s,s)/Ag(s,s)/Ti(Cu,Al)2/TiAl,当钎焊温度T=1 223 K,保温时间t=10 min时接头的剪切强度达到223.3 MPa;采用Ti-Zr-Ni-Cu钎料时在界面出现了Ti2Ni,Ti(Cu,Al)2等多种金属间化合物,当钎焊温度T=1 123 K,保温时间t=10 min时接头的剪切强度达到139.97 MPa.     

SiCP/Al复合材料的真空扩散钎焊

文中采用Al/Cu/Al复合箔扩散钎焊SiC_P/Al复合材料,采用SEM,EDS,XRD分析接头界面组织,研究了钎焊温度对接头界面组织及力学性能的影响,并结合Al-Cu二元相图分析接头形成机制.结果表明,固定连接压力为1 MPa,保温时间为10 min,当钎焊温度从590℃升至640℃,接头界面产物由Al₂Cu+αAl共晶组织转变为断续的Al₂Cu金属间化合物,Al-Cu液相向两侧母材扩散的距离增加,接头的抗剪强度呈现先增大后减小的变化趋势.当钎焊温度为620℃,保温时间为10 min,连接压力为1 MPa时,接头的抗剪强度达到最大值69 MPa.     

TiAl/Ni基合金反应钎焊接头的微观组织及剪切强度(英文)

以Ti为中间层,对TiAl基金属间化合物与Ni基高温合金进行反应钎焊连接,研究反应钎焊接头的界面微观结构及剪切强度。通过实验发现,熔融中间层与两侧母材反应剧烈,生成连续的界面反应层。典型的界面微观结构为GH99/(Ni,Cr)ss(γ)/TiNi(β2)+TiNi2Al(τ4)+Ti2Ni(δ)/δ+Ti3Al(α2)+Al3NiTi2(τ3)/α2+τ3/TiAl。当钎焊温度为1000°C,保温时间10min时,所得接头的剪切强度最高为258MPa。进一步升高钎焊温度或延长保温时间,会引起钎缝组织中组成相粗化和脆性金属间化合物层的生成,从而导致接头剪切强度的降低。     

以铜和Cu-Ti作为中间层的TiAl/GH3536扩散焊

采用铜箔和Cu-Ti合金作为中间层进行了TiAl和GH3536的扩散焊试验.以铜箔作为中间层在935℃/10 MPa/1 h参数下获得的焊缝组织以Ti（Cu,Al）2,AlCu2Ti和AlNi2Ti相为主,焊缝中存在裂纹.接头室温平均抗剪强度仅有31 MPa.以Cu-Ti合金作为中间层在935℃下采用三种不同参数进行了TiAl和GH3536的液相扩散焊试验.当加压3 MPa,保温10 min时,扩散焊缝中央还存在着宽度约5μm的残留相.保温时间延长至1 h,焊缝形成了较为均匀的分层组织,获得的接头室温抗剪强度最高,达180 MPa.增大压力至20 MPa,保温2 h获得的接头中出现AlNi2Ti相,接头平均室温抗剪强度下降至90 MPa.     

Brazing of Coated Al Foil Filler to AIN CeramicEI北大核心CSCD

The wettabilities of molten metals on ceramics are poor normally. In order to improve the wettability, all existing ceramic brazing methods introduce a compound transition layer formed by the reaction of active metal and ceramic. The transition layer between brazing seam and ceramic however creates negative effect on the properties of brazing joints. Although Al is the scarce metal which can wet some ceramics such as AIN and Al2O without reaction, the difficulty of removing oxide layer on surface prevents it being ceramic brazing filler. This work proposed a kind of coated Al foil filler able to remove its own Al2O3 film and an elevating temperature brazing process to enhance Al/AIN joint strength. Removing Al2O3. film effect of vapor deposited Ni/Al double layer film on Al foil and the effect of brazing temperature on improving joint strength were studied. The results showed that due to buried by Ni/Al double layer film, Al2O3 film on Al foil original surface broken and was swept in Al-1%Ni (atomic fraction) alloy liquid during heating and melting process. As a result, the direct brazing of Al to AIN without interface reaction transition layer was realized. The joint strength was significantly enhanced by elevating brazing temperature. When brazing at 680 degrees C, the joint fractured along the interface between Al seam and AIN and the sheer strength was 79 MPa because of Al liquid not wetting AIN. With the elevating of brazing temperature, the wettability and interface strength of Al/AIN improved. The fracture gradually transferred to brazing seam from interface. The joint strength increased and reached to the maximum value of 146 MPa at 840 degrees C.     

Infrared joining strength and interfacial microstructures of Ti–48Al–2Nb–2Cr intermetallics using Ti–15Cu–15Ni foil

Infrared joining of Ti–48Al–2Nb–2Cr using Ti–15Cu–15Ni (wt%) foil as brazing filler metal was investigated at the temperature range of 1100∼1200°C for 30∼60 s in a flowing argon environment. The compressive tests show three types of fracture morphologies in which type I fails at the joint interface, but types II and III are fractured in the base-metal with the crack direction parallel to and perpendicular to the loading axis, respectively. Most of joined specimens were fractured through the base metal indicating that the infrared joined interface has relatively good joint strength. The compressive strength of type I specimen is about 319–322 MPa. Experimental results show that the shorter the real holding time or the higher the joining temperature, the larger the strength variation will be. The observed interfacial microstructures of Ti–48Al–2Nb–2Cr joint interfaces indicate that seven characteristic zones can be distinguished in the joint interfaces and each characteristic structure corresponds to one or more stable phases at T_w temperature. The observed microstructures and their evolutions of each zone are explained in detail in this study. The major difference between joint interfaces of Ti–48Al–2Nb–2Cr and Ti₅₀Al₅₀ alloys takes place on the base-metal interface zone and the columnar two-phase zone. The existence of Nb and Cr atoms in Ti–48Al–2Nb–2Cr alloy also has some influences on the microstructural evolution of the columnar two-phase zone and the continuous α₂-layer.     

SiC陶瓷与TC4钛合金反应钎焊的研究

采用Ｃｕ箔对常压烧结的ＳｉＣ陶瓷与ＴＣ４钛合金进行了接触反应钎焊,并对接头的微观组织,形成机理和室温强度进行了研究。结果表明,利用Ｃｕ箔可以在低于其熔点的温度实现ＳｉＣ与ＴＣ４钛合金的连接。接头界面具有明显的层状结构,即由Ｔｉ－Ｃｕ－Ｓｉ合金层,Ｔｉ－Ｃｕ合金层和富Ｔｉ的Ｔｉ－Ｃｕ－Ａｌ合金层组成。在１２７３Ｋ的条件下连续５ｍｉｎ,接头室温关照切达到１８６ＭＰａ。     

Microstructure and strength of brazed joints of TiB2 cermet to TiAl-based alloys

In this study, TiB2 cermet and TiAl-based alloy are vacuum brazed successfully by using Ag-Cu-Ti filler metal.The microstructural analyses indicate that two reaction products, Ti ( Cu, Al ) 2 and Ag bused solid solution ( Ag ( s. s ) ) , are present in the brazing seam, and the iuterface structure of the brazed joint is TiB2/TiB2 Ag ( s. s ) /Ag ( s. s ) Ti ( Cu,Al)2/Ti( Cu, Al)2/TiAl. The experimental results show that the shear strength of the brazed TiB2/TiAl joints decreases us thebrazing time increases at a definite brazing temperature. When the joint is brazed at 1 223 K for 5 min, a joint strength up to 173 MPa is achieved.     

TiAl与Ni基合金接触反应钎焊接头界面组织及性能

以Ti为中间层实现了TiAl与Ni基合金的接触反应钎焊。采用扫描电镜和电子探针等手段对钎焊接头的界面结构及生成相进行分析,并对接头剪切强度进行测试。结果表明:当钎焊温度为960℃时,钎缝主要由Tiss和Ti2Ni组成;当钎焊温度从960℃升高到1000℃时,钎缝中生成Ti-Al及Al-Ni-Ti化合物,典型界面结构为:GH99/(Ni,Cr)ss/Ti2Ni+AlNi2Ti+TiNi/Ti3Al+Al3NiTi2/Ti3Al+Al3NiTi2/TiAl;钎焊温度继续升高,Ti3Al和Al3NiTi2变得粗大,导致接头性能下降。当钎焊温度为1000℃,保温10min时,接头剪切强度达到最大值233MPa。随钎焊温度的升高,钎缝厚度先增加后减小。     

Vacuum brazing Mo using Ti-Ni-Nb braze alloys

A novel approach of brazing Mo using three clad Ti-Ni-Nb foils, 40Ti-35Ni-25Nb, 50Ti-35Ni-15Nb and 60Ti-15Ni-25Nb in wt.%, has been performed in the experiment. Similar microstructural evolution of the joint is observed for three foils. The joint using 60Ti-25Ni-15Nb foil brazed at 1250 °C for 600 s demonstrates the highest bending strength of 526 MPa. The clad Ti-Ni-Nb foils show potential in brazing Mo for industrial application.     

活性金属部分瞬间液相连接氮化硅陶瓷的研究

采用Ti/Cu/Ti多层中间层在1273 K温度下进行氮化硅陶瓷部分瞬间液相连接,考察了保温时间对连接强度的影响,并对连接界面进行了SEM,EPMA和XRD分析.结果表明,通过Cu-Ti二元扩散促使液相与氮化硅发生界面反应,形成Si3N4/TiN/Ti5Si3+Ti5Si4+TiSi2/TiSi2+Cu3Ti2(Si)/Cu的梯度层.保温时间影响接头反应层厚度,从而影响接头的连接强度根据活性金属部分瞬间液相连接陶瓷的界面行为,建立了活性金属部分瞬间液相连接陶瓷的理论模型.该模型较好地解释了Ti/Cu/Ti和Ti/Ni/Ti连接氮化硅陶瓷的异同点和连接工艺参数的选择.     

钎焊工艺对Ni-14Cr-10P-x Ti钎料连接C/C复合材料组织和性能的影响

用真空熔炼、惰性气体雾化的方法制备Ni-14Cr-10P金属粉末,再加入Ti粉和高分子聚合物高速搅拌分散制备了Ni-14Cr-10P-x Ti膏状活性钎料。用制备的焊膏在真空钎焊炉中钎焊C/C复合材料,然后测试了钎焊接头的抗剪切强度,采用SEM、EDS、XRD等方法对接头微观组织进行了分析。结果表明,在钎焊温度1000℃,保温时间30min时,接头获得了最高的抗剪切强度,然后随着钎焊温度的上升、保温时间延长,钎焊接头强度下降;添加Ti元素加快了钎焊强度随温度和保温时间的增加而下降的速度,结合微观组织结构,对Ti元素加入后钎焊强度随温度和保温时间增加而下降更为迅速的原因进行了分析。     

SiO2-BN复相陶瓷润湿性及其接头微观组织

采用座滴法开展Ag-21Cu-4.5Ti合金钎料对SiO₂-BN复相陶瓷润湿与铺展行为研究. 利用SEM、XRD分析润湿界面微观组织以及形成机理. 通过调控SiO₂-BN复相陶瓷中BN含量,研究Ag-21Cu-4.5Ti/SiO₂-BN复相陶瓷润湿体系的润湿模型. 结果表明,Ag-21Cu-4.5Ti/SiO₂-BN复相陶瓷润湿体系的典型界面反应产物为TiN和TiB₂,随着体系BN含量的增加,润湿性逐渐变好. 对SiO₂-BN复相陶瓷与Nb进行钎焊试验,典型界面组织为SiO₂-BN复相陶瓷/TiN + TiB₂/Ti₂Cu + (Ag,Cu)/(βTi,Nb)/Nb. 接头抗剪强度随着钎焊时间升高先增大后减小,当钎焊温度为880 ℃,保温时间10 min时,钎焊接头抗剪强度最高,到达39 MPa.     

Ti600和Ni-25%Si合金钎焊接头性能及失效机理分析

采用Ti-Zr-Ni-Cu非晶钎料对高温钛合金Ti600和Ni-25%Si (原子分数,%)合金进行钎焊试验,重点研究了钎焊温度对镍硅与钛合金接头组织及性能的影响,结合接头组织特征及断口结构分析阐明了Ti600和Ni-25%Si合金钎焊接头的失效机理. 结果表明,钎缝内部包含多个区域,随着连接温度从900 ℃上升至980 ℃,包含(Ti,Zr)₂Si和Ti₂Ni相的区域逐渐消失,包含Ti₅Si₃和Ti₂Ni相的区域逐渐变厚,最终占据全部钎缝. 力学性能分析表明,随着钎焊温度的升高,接头抗剪强度先增大后降低. 当钎焊温度为960 ℃时,接头的抗剪强度能够达到峰值177 MPa. 在脆性Ti₂Ni相基体上弥散分布的Ti₅Si₃相颗粒破坏了Ti₂Ni相的连续性,阻碍了裂纹在钎缝内部的扩展是钎焊接头抗剪强度提升的根本原因.     

弥散强化铜基复合材料钎焊接头强度

从冶金方面就如何改善Al2O3P颗粒与钎缝的化学相容性及工艺参数对钎焊接头力学性能的影响进行了初步探讨。研究结果表明。当保温时间较短时，由于钎缝中含有较多的Al2O3P颗粒相，且有偏聚的趋势，钎焊接头强度较低；延长保温时间，钎料中活性组元Ti与Al2O3P颗粒反应，可以有效控制Al2O3P含量，从而减缓其不利影响，使钎焊接头强度大幅度提高。     

Ni—Ti焊料部分液相瞬间连接高纯Al2O3—Kovar工艺的研究

通过Ti-Ti活性焊粒部分液相瞬间连接工艺，实现了高纯Al2O3陶瓷和可伐合金（Kovar）的气密性连接。结果表明焊缝区呈现明显的“三明治”夹层结构，两侧主要为Ti2Ni金属间化合物层，中间为较厚的Ti固溶体层。接头强度最初随保温时间延长增加，但与焊接温度之间没有明显的单调关系。     

5005铝合金与1Cr18Ni9Ti的真空钎焊分析

采用Al-Si-Mg钎料成功实现了5005铝合金与1Cr18Ni9Ti不锈钢的真空钎焊,借助扫描电镜、能谱分析仪和X射线衍射仪对焊后接头界面组织进行分析,同时对接头抗剪强度进行测试.结果表明,焊后接头界面结构从1Cr18Ni9Ti不锈钢侧到5005铝合金侧的界面组织依次为FeAl,FeAl₃,Fe_mAl_n+αAl.随着钎焊温度的升高或保温时间的延长,接头抗剪强度均呈现先升高后降低的变化趋势.当钎焊温度为580℃,保温时间为15 min时,接头抗剪强度达到最大值49 MPa.接头断裂形式受钎焊温度的影响,当钎焊温度较低时,接头断裂于铝合金侧氧化膜层及Fe_mAl_n+αAl反应层;温度升高至580℃时,接头断裂于Fe_mAl_n+αAl反应层中,接头抗剪强度最高.     

填充泡沫Ti/AlSiMg的SiC陶瓷钎焊接头的组织与性能

为丰富SiC陶瓷钎焊所用钎料的设计思路,提出了一种泡沫Ti/AlSiMg新型复合钎料,通过Ti元素的溶入提高钎料与SiC陶瓷之间的界面结合力,利用泡沫Ti与Al基钎料之间的界面反应获得原位增强的钎缝,从而提升接头力学性能. 采用钎焊温度700 ℃、保温时间60 min和焊接压力10 MPa进行SiC陶瓷真空钎焊,利用光学显微镜、扫描电镜、能谱分析、X射线衍射、电子探针和万能试验机对接头组织、成分和性能进行分析,探索泡沫Ti/AlSiMg复合钎料在SiC陶瓷钎焊中的可用性. 结果表明,填充泡沫Ti/AlSiMg复合钎料所得接头结构为SiC/Al/Ti(Al,Si)₃/Ti(Al,Si)₃原位增强Ti基钎缝/ Ti(Al,Si)₃/Al/SiC,断裂发生在铝合金界面层和SiC陶瓷之间,Ti元素的溶入提高了铝合金界面层与SiC陶瓷之间的界面结合力,接头抗剪强度达111 MPa.     

TC4钛合金和YG8硬质合金的钎焊工艺

针对钛合金和YG8型硬质合金异种材料的真空钎焊工艺和接头可靠性问题展开研究,采用润湿性实验、金相显微镜、显微硬度计、万能拉伸试验机、扫描电子显微镜等实验及测试手段,对Ag94AlMn钎焊试样接头的微观组织结构、维氏硬度、接头剪切强度等进行试验分析。结果表明,银基钎料与钛合金、硬质合金界面冶金结合良好,焊缝表面组织均匀,无微裂纹。钎缝组织为Ag基固溶体,硬质合金母材Co、W元素和钛合金母材Ti、V元素向钎缝内扩散甚少,几乎不发生母材溶蚀;TC4与YG8真空钎焊异种金属真空钎焊,选择银基钎料以及钎焊温度920℃、保温时间10 min的工艺参数,接头剪切强度最高。