Ti-Si共晶钎料的制备及其对SiC陶瓷可焊性

采用海绵钛和单晶硅为原料,通过非自耗电弧熔融技术制备91.5Ti-8.5Si(wt%)和22Ti-78Si(wt%)共晶钎料.在真空中1400℃×10min条件下,研究了共晶钎料对SiC陶瓷的润湿性能和界面反应.结果表明:两种共晶钎料对SiC陶瓷均具有良好的润湿性能,润湿角分别约为10°和25°.在润湿实验后,91.5Ti-8.5Si(wt%)钎料和SiC陶瓷分离,22Ti-78Si (wt%)钎料和SiC陶瓷之间结合紧密.在润湿实验的温度制度下,用22Ti-78Si (wt%)钎料(厚度为0.2mm)对SiC陶瓷进行了初步连接,接头的抗弯强度为72MPa.采用SEM、EDS、XRD等检测手段对钎料的形貌和物相组成、钎料和SiC陶瓷的界面结合情况进行了表征,揭示了钎料对SiC陶瓷润湿性和界面反应的机理.     

SiC陶瓷真空钎焊接头显微组织和性能

在高真空条件下采用Ti-35Zr-35Ni-15Cu(质量分数/%)钎料对SiC陶瓷进行了钎焊连接,研究了接头界面组织的形成过程以及工艺参数对接头性能的影响。结果表明:钎料与SiC陶瓷发生了复杂的界面反应,生成了多种界面产物。当钎焊温度为960℃,保温时间为10min时,SiC陶瓷侧形成了连续的TiC和Ti5Si3+Zr2Si层,同时Ti5Si3+Zr2Si向钎缝中心生长呈长条状。SiC陶瓷到接头钎缝中心的显微组织依次为:SiC/TiC/Ti5Si3+Zr2Si/Zr(s,s)/Ti(s,s)+Ti2(Cu,Ni)/(Ti,Zr)(Ni,Cu)。钎焊温度为960℃,保温时间为30min时,长条状的Ti5Si3+Zr2Si贯穿了整个接头。钎焊接头强度随着钎焊温度的升高和钎焊时间的延长都呈现先增大后减小的趋势。当钎焊温度为960℃,保温时间为10min时,接头的剪切强度最高,达到了110MPa。     

SiC陶瓷与316L不锈钢真空活性钎焊北大核心CSCD

采用Ag-Cu-Ti活性钎料,通过真空钎焊方法进行了SiC陶瓷与316L不锈钢的连接,研究了接头的界面组织、特征点成分和物相,并探讨了钎焊温度(800～930℃)、保温时间(0～30 min)对接头界面组织和连接强度的影响。结果表明,SiC陶瓷与316L不锈钢钎焊抗剪断口均发生在SiC陶瓷与钎料连接界面处,由于活性元素Ti的作用,在陶瓷与钎料的界面处形成了连续的反应层,反应生成了Ti C和Ti5Si3;在316L不锈钢与钎料的界面处,生成了Fe-Ti化合物和Cu-Ti化合物。随着钎焊温度升高及保温时间延长,接头强度均呈现出一个峰值,在温度为900℃,保温20 min的工艺条件下可获得最大接头抗剪强度。     

SiC陶瓷与316L不锈钢真空活性钎焊

采用Ag-Cu-Ti活性钎料,通过真空钎焊方法进行了SiC陶瓷与316L不锈钢的连接,研究了接头的界面组织、特征点成分和物相,并探讨了钎焊温度(800～930℃)、保温时间(0～30 min)对接头界面组织和连接强度的影响。结果表明,SiC陶瓷与316L不锈钢钎焊抗剪断口均发生在SiC陶瓷与钎料连接界面处,由于活性元素Ti的作用,在陶瓷与钎料的界面处形成了连续的反应层,反应生成了Ti C和Ti5Si3;在316L不锈钢与钎料的界面处,生成了Fe-Ti化合物和Cu-Ti化合物。随着钎焊温度升高及保温时间延长,接头强度均呈现出一个峰值,在温度为900℃,保温20 min的工艺条件下可获得最大接头抗剪强度。     

Al-Ti合金钎焊SiC陶瓷接头界面微观结构与力学性能

SiC陶瓷具有优异的综合性能, 通过钎焊获得高强度接头是其获得广泛应用的重要前提。研究采用Al-(10, 20, 30, 40)Ti(Ti的名义原子含量10%、20%、30%、40%)系列合金, 在1550 ℃条件下, 对SiC陶瓷进行钎焊30 min。当中间层厚度为~50 μm时, SiC钎焊接头的平均剪切强度处于100~260 MPa范围内。当采用Al-20Ti合金作为钎料时, 随着中间层厚度从~100 μm减小至25 μm, 钎焊接头的平均强度逐渐提高, 且最大强度~315 MPa。同时, 钎焊中间层中(Al)相逐渐减少直至消失, 只留下Al₄C₃、TiC和(Al,Si)₃Ti相。SiC/Al-20Ti/SiC钎焊接头的断裂主要发生在靠近中间层/陶瓷界面位置的陶瓷基体内。     

用Ti50Cu＋W钎料连接Si／SiC复相陶瓷与殷钢的研究

采用真空钎焊方法,以Ti50Cu W钎料连接Si/SiC复相陶瓷与殷钢.观察分析了获得接头显微组织结构,测定了接头的力学性能,研究了工艺参数和增强相W含量对接头组织结构和力学性能的影响.研究结果表明:采用Ti50Cu W钎料连接Si/SiC复相陶瓷与殷钢,可获得连接良好、组织致密的接头,W含量30%(体积分数),钎焊温度970℃,保温时间5rain时,接头室温剪切强度达到最大值106MPa.     

Cu-Ni-Ti系合金钎料对Si_3N_4陶瓷自身及其与金属的连接研究

系统研究了Cu-Ni-Ti系合金钎料对Si3 N4陶瓷的润湿性 ,并使用不同形式的钎料进行了Si3 N4/Si3 N4的连接 .使用真空熔炼合金作为钎料 ,获得的Si3 N4/Si3 N4接头强度值并不理想 ,分析其原因 ,采用膏状钎料改善钎料成分的均匀性 ,并重新设计了四种成分的钎料 ,其中钎料Cu -Ni5～ 2 5 -Ti1 6～ 2 8-Br(B) / %对应的Si3 N4/Si3 N4接头强度最高 ,在 1 3 5 3K ,1 0min的真空钎焊条件下三点弯曲强度达 3 3 8.8MPa.制备了上述合金的急冷态钎料 ,使连接强度进一步提高至 40 2MPa,接头呈现较稳定的高温性能 .使用这种急冷态钎料还获得了室温及高温强度均较理想的Si3 N4/ 1 .2 5Cr-0 .5Mo钢接头 .     

SiC陶瓷真空钎焊接头的组织及性能分析

采用BNi-5钎料对SiC陶瓷进行真空钎焊,获得了力学性能良好的SiC钎焊接头,并对焊缝的微观结构和形成过程进行了分析。研究结果表明,Ni基钎料与SiC母材发生反应生成层状界面反应层结构,所形成的SiC钎焊接头钎缝微观形貌可以表述为:SiC母材/石墨+Ni_2Si/Ni_2Si/石墨+Ni_2Si/Cr_3Ni_2SiC/Ni+Cr_3Ni_5Si_2/Cr_3Ni_2SiC/石墨+Ni_2Si/Ni_2Si/石墨+Ni_2Si/SiC母材。所得SiC钎焊接头常温力学性能较好,平均钎焊接头剪切强度可达到124 MPa。Ni基钎料钎焊SiC陶瓷接头的断裂位置位于钎料与陶瓷基体间的界面反应层,主要原因是界面反应层中Ni_2Si和Cr_3Ni_2SiC等脆性化合物在钎焊接头拉伸变形过程中会产生应力集中,在残余钎焊应力的共同作用下钎焊接头发生断裂。     

高体积比SiCp/6063Al复合材料的铝基钎料制备及钎焊工艺研究

采用快速甩带技术制备了(Al-10Si-20Cu-0.05Ce)-1Ti(质量分数/％)急冷箔状钎料,并对60％体积分数的SiCp/6063Al复合材料进行真空钎焊实验,然后对钎料及接头的显微组织与性能进行测定和分析.结果表明,急冷钎料的微观组织细小、成分均匀,厚80～90μm,主要包含Al、CuAl2、Si和Al2Ti等相.当升高钎焊温度(T/℃)或延长保温时间(t/min),SiCp/钎料界面的润湿性改善,6063Al基体/钎料间互扩散和溶解作用增强,接头连接质量逐渐提高.当T=590℃、t=30 min时,接头抗剪强度达到112.6MPa;当T=590℃、t=50 min时,少量小尺寸SiCp因液态钎料排挤而分散于钎缝,因加工硬化而使接头强度递增7.3％.然而,当T≥595℃、t≥60 min时,SiCp偏聚于钎缝,导致接头组织恶化,且剪切断裂以脆性断裂为主.综合考虑钎焊成本与接头强度使用要求,确定最佳钎焊工艺为590℃、30 min.     

采用Ag-Cu-Ti钎料真空钎焊SiO2f/SiO2复合陶瓷与C/C复合材料

分别在880℃/10min和880℃/60min规范下,采用Ag-Cu-Ti活性钎料实现了SiO2f/SiO2复合陶瓷与C/C复合材料的真空钎焊连接,通过电子探针(EPMA)、能谱仪(XEDS)和X射线衍射仪(XRD)分析了接头微观组织,室温下测试了接头的抗剪强度。结果表明:两种规范下所得接头界面结合良好,接头中靠近两侧母材均形成了一层扩散反应层,钎缝基体主要由均匀的共晶组织组成。880℃/10min规范下钎焊接头界面产物依次为:SiO2f/SiO2→Ti4O7→Ti5Si4+Cu(s,s)+Ag-Cu共晶合金→TiC→C/C;对于880℃/60min规范下的接头,界面组织结构与保温10min的接头基本类似,但是不存在Cu(s,s),并且接头反应层明显增厚。880℃/60min条件下所得钎焊接头剪切强度平均值为16.6MPa。     

Joining of C/C composite to TC4 using SiC particle-reinforced brazing alloy

Silicon carbide particles were used as reinforcement in the Ag-26.7Cu-4.6Ti (wt.%) brazing alloy for joining C/C composite to TC4 (Ti-6Al-4V, wt.%). The mechanical properties of the brazed joints were measured by shear strength testing. The effects of the volume percentage of SiC particles on the microstructures of the brazed joints were investigated. It is shown that the maximum shear strength of the joints is 29 MPa using 15 vol.% SiC in the brazing alloy which is greater than that with Ag-26.7Cu-4.6Ti brazing alloy alone (22 MPa). Ti is reacted with SiC particles, forming Ti–Si–C compound in the particle-reinforced brazing alloy. Due to this, more SiC particles in the brazing alloy, the thickness of TiC/TiCu reaction layer near C/C composite decreases. Moreover, SiC particles added to the brazing alloy can reduce the CTE of the brazing alloy which results in lower residual stress in the C/C composite-to-metal joint. Both of the above reasons lead to the increasing of the shear strength of the brazed joints. But excessive SiC particles added to the brazing alloy lead to pores which results in poor strength of the brazed joint.     

Cu-P-Sn-Ni钎料真空钎焊MGH956合金的研究

为扩展Cu-P基钎料在连接MGH956合金中的应用,采用新型Cu-P-Sn-Ni钎料对MGH956合金在800~890℃进行了真空钎焊,研究了不同钎焊温度和保温时间对焊缝组织及力学性能的影响.结果表明:在所研究的钎焊温度范围内保温5 min均可获得成形效果良好的钎焊接头,其主要由钎缝中心区和界面反应层组成,其中,钎缝中心区由α(Cu)固溶体基体和化合物Cu_3P+(Fe,Ni)_3P+FeCr组成,反应层由α(Fe)固溶体、Fe_3P和Cu_3P组成;随着钎焊温度的升高,反应层厚度逐渐增加,钎缝中心区中的化合物Cu_3P+(Fe,Ni)_3P+FeCr的形态也随之发生明显改变;各钎焊温度下获得的钎焊接头经室温拉伸,断裂均发生在钎缝中心区,断口形貌呈现韧性和脆性的混合断裂特征.830℃钎焊5 min的接头抗拉强度最大,为510.3 MPa,达到了母材抗拉强度的70.9%.     

SiC/SiC-哈氏合金异质连接机制及其氟熔盐腐蚀特性分析

以Cu-2.67Ni钎料, 采用钎焊工艺获得了SiC/SiC复合材料-哈氏合金异质接头, 并研究了其在800 ℃的FLiNaK熔盐中的腐蚀行为。利用不同手段表征了接头微观结构和氟熔盐腐蚀行为。结果表明, Ni、Cr、Mo等合金元素以及SiC中的Si元素发生互扩散。Cr元素替代Ni元素, 在焊料-复合材料界面富集并形成不连续碳化物层。高温钎焊加速Ni扩散并侵蚀SiC, 低温钎焊导致焊料熔融不充分。钎焊过程中的元素扩散改变了哈氏合金的组成,导致其耐腐蚀性能恶化。Cr与Si的选择性溶出导致钎焊接头及合金的腐蚀损伤, 这与热力学计算结果一致。     

采用BNi-7的Ti（C，N）基金属陶瓷与17-4PH沉淀硬化不锈钢的真空钎焊研究

采用镍基共晶钎料BNi-7对Ti（C,N）基金属陶瓷与17—4PH沉淀硬化不锈钢行了真空钎焊连接。研究了钎焊温度和焊缝厚度对焊接接头力学性能和微观结构的影响。结果表明,BNi-7对金属陶瓷粘结相具有较强的溶解能力,这是熔降元素（磷）能够在金属陶瓷侧大范围分布、钎焊接头获得良好界面结合的主要原因。随钎焊温度升高,磷在金属...     

Brazing of SiC to a wrought nickel-based superalloy using CoFeNi(Si, B)CrTi filler metal

Newly-developed CoFeNi(Si, B)CrTi brazing filler metal was used for joining of SiC to a wrought nickel-based superalloy (GH3044). The brazing alloy was fabricated into brazing foils by a rapid solidifying technique, and the brazing temperature was fixed at 1150 °C. The SiC/GH3044 joints using single interlayer Ni or triple interlayers of Ni/W/Ni showed very low strength, and this was because the Ni severely interfered with the normal reactions between the SiC and the brazing alloy. When using triple interlayers of Kovar/W/Ni for the SiC/GH3044 joining, the joint strength was remarkably elevated to 62.5-64.6 MPa. Kovar has a low coefficient of thermal expansion. Moreover, when Kovar was used as an interlayer neighboured to the brazed SiC, it basically ensured the normal interfacial reactions between the brazed SiC and the used brazing alloy. These two factors should account for the improvement of the joint strength.     

High-resolution electron microscopy of a SiC/SiC joint brazed by a Ag-Cu-Ti alloy

A high-resolution electron microscope observation (HREM) was performed on the joined portion of a brazed polycrystalline or single crystal SiC to itself with (Ag-28wt% Cu) + 2wt% Ti alloy foil. The brazing was done under vacuum at temperatures of 800° C to 950° C with a holding period of up to 30 min. Reaction products formed at the joined interface were found to be mainly TiC. In the specimen brazed at 800° C with the holding time of 0 min, reaction product TiC formed itself into small crystallites with a diameter of less than 20 nm, and an amorphous like layer was found between SiC and TiC. On the other hand, TiC was formed as a layer along the joined interface for the specimen brazed at 950° C for the holding time of 30 min. Lattice matching of SiC to TiC crystals appeared to be good so the high bonding strength of the joint was attributed to the formation of this epitaxial interface between SiC and TiC.     

Zr-Cu-Ni非晶钎料真空钎焊TiAl合金/316L不锈钢接头的界面组织与剪切性能

采用自主设计制备的Zr-42.9Cu-21.4Ni非晶钎料对TiAl合金和316L不锈钢进行真空钎焊,研究钎焊温度和钎焊时间对TiAl合金/316L不锈钢异种金属接头微观组织和剪切性能的影响。结果表明：钎缝界面可以划分为6个不同的反应层。1040 ℃/10 min下制备的钎焊接头从TiAl合金到316L不锈钢侧界面组织依次为γ(TiAl)+AlCuTi/α₂(Ti₃Al)+AlCuTi/AlCu+ZrCuNi+FeZr/Cu₈Zr₃+ZrCuNi+TiFe+Fe₂Zr/FeZr+Fe₂Zr+TiFe₂+ZrCu/α-(Fe, Cr)。随着钎焊温度的升高,接头的抗剪强度先升高后降低。当钎焊温度为1040 ℃和钎焊时间25 min时,接头抗剪强度达到最大值162 MPa。断口分析表明,接头在FeZr+Fe₂Zr+TiFe₂+ZrCu界面处萌生,沿着Cu₈Zr₃+ZrCuNi+TiFe+Fe₂Zr和α-(Fe, Cr)扩展,呈解理断裂。     

活性钎焊法连接碳化硅陶瓷的连接强度和微观结构

采用三元Ag-Cu-Ti活性焊料连接常压烧结碳化硅陶瓷,研究了反应温度、保温时间等钎焊工艺对碳化硅陶瓷连接强度的影响,分析了连接界面的微观结构和反应产物. 实验结果表明,在实验范围内,钎焊温度和保温时间对碳化硅陶瓷的连接强度均有峰值,四点弯曲强度最高达到342MPa,随着钎焊温度的升高,界面反应层厚度增加,连接强度提高,但过高的钎焊温度引起焊料的挥发而使连接强度下降. 焊料中的活性元素Ti与碳化硅发生反应在连接界面形成均匀致密的反应层,反应层厚度约1μm,XRD和EDX能谱分析结果表明反应产物是TiC和Ti₅Si₃.     

Effect of mechanical milling on Ni–TiH2 powder alloy filler metal for brazing TiAl intermetallic alloy: The microstructure and joint's properties

A TiH₂–50 wt.% Ni powder alloy was mechanically milled in an argon gas atmosphere using milling times up to 480 min. A TiAl intermetallic alloy was joined by vacuum furnace brazing using the TiH₂–50 wt.% Ni powder alloy as the filler metal. The effect of mechanical milling on the microstructure and shear strength of the brazed joints was investigated. The results showed that the grains of TiH₂–50 wt.% Ni powder alloy were refined and the fusion temperature decreased after milling. A sound brazing seam was obtained when the sample was brazed at 1140 °C for 15 min using filler metal powder milled for 120 min. The interfacial zones of the specimens brazed with the milled filler powder were thinner and the shear strength of the joint was increased compared to specimens brazed with non-milled filler powder. A sample brazed at 1180 °C for 15 min using TiH₂–50 wt.% Ni powder alloy milled for 120 min exhibited the highest shear strength at both room and elevated temperatures.