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1.
研究了紫铜钎料焊接车载储罐外筒体夹芯强化结构件Q235钢的钎焊工艺,考虑了不同钎料厚度和外加载荷对钎焊接头的影响,借助EDS和金相显微镜分析了钎焊接头的元素扩散情况和界面微观组织结构,并通过剪切试验测试不同钎焊接头的力学性能。结果表明:钎料厚度越小,钎料对母材润湿效果越好;钎焊夹具上作用的外加载荷有助于提高接头强度。当钎料厚度为0.057mm,外加5MPa载荷的情况下,钎料对母材润湿效果最好,接头剪切强度可达140MPa,可以满足车载储罐外筒体夹层结构所需的力学性能。 相似文献
2.
在真空度为10-3 Pa、加热速率为20 ℃/min、加热温度为565℃的条件下,使用Al-5 Si-28Cu-Zn-Ti钎料,采用不同保温时间分别对体积分数20%的SiCP/A356复合材料进行真空钎焊,测定了钎焊接头的抗剪切强度以及接头显微硬度,分析了不同保温时间对钎焊接头性能的影响.结果表明,接头抗剪强度和焊缝硬度均随保温时间的延长先增加后减小.当保温时间25 min时,钎焊接头抗剪强度最大,为28.35 MPa,此时,焊缝硬度最高,为127.2HV.对比不同保温时间下钎焊接头综合性能,25 min保温时间最好. 相似文献
3.
采用三种钎料对1Crl8Ni9Ti不锈钢进行真空和电子束钎焊,分析了钎焊接头力学性能。结果表明:纯铜、BHP-1、BNi-2钎料电子束钎焊接头的抗剪切强度均高于其真空钎焊接头的抗剪切强度值。不论是电子束钎焊还是真空钎焊.三种钎料中纯铜钎料钎焊接头力学性能最好。 相似文献
4.
采用三种钎料对1C r18N i9T i不锈钢进行真空和电子束钎焊,分析了钎焊接头力学性能。结果表明:纯铜、BПP-1、BN i-2钎料电子束钎焊接头的抗剪切强度均高于其真空钎焊接头的抗剪切强度值。不论是电子束钎焊还是真空钎焊,三种钎料中纯铜钎料钎焊接头力学性能最好。 相似文献
5.
分别采用CuTi、CuTi+B和CuTi+TiB2钎料,在钎焊温度为930℃,保温时间为10min条件下,钎焊连接Al2O3和TC4合金。通过扫描电子显微镜、透射电子显微镜和压剪试验等方法,研究了接头中生成的TiB晶须对接头组织结构及力学性能的影响。结果表明:B或TiB2粉的添加均可在钎焊接头中原位自生TiB晶须。当钎料中添加B粉时,接头中原位自生的TiB晶须比添加TiB2时的尺寸小。原位自生的TiB晶须可将Al2O3/TC4合金钎焊接头界面分为5个区域,各区分布满足延性–刚性–延性结构,此结构有助于减小降低接头残余应力,提高接头抗剪强度。采用CuTi+TiB2钎料时,Al2O3/TC4合金钎焊接头的抗剪强度最大为143 MPa,比用CuTi钎料时所获接头强度提高了239%。 相似文献
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研究了钎焊温度对氧化铝陶瓷与1Cr18Ni9Ti不锈钢接头强度的影响,探讨了钎焊接头的热震抗力。结果表明,由于陶瓷/钎料界面反应和界面残余应力的综合影响,随着钎焊温度的增加,接头强度先增加然后逐渐孤低,850℃钎焊时接头强度最高。 相似文献
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在大气环境下使用PbO-SiO2-Al2 O3玻璃钎料对65vol%SiCp/6063Al复合材料进行440~500℃之间的低温钎焊.通过对玻璃钎料润湿性能的研究确定了钎焊试验的温度和时间范围;通过剪切试验研究了钎焊工艺参数对接头强度的影响.试验结果表明,随温度的升高,玻璃钎料对母材的润湿性会提高,但温度超过480℃后,润湿角下降不明显.在大气环境下,通过使用玻璃钎料可实现65vol%SiCp/6063Al复合材料间较好的钎焊连接效果.钎焊工艺参数对接头强度影响很大,在钎焊温度为480℃,保温时间为30 min时,钎焊接头剪切强度最大,达到41.77 MPa. 相似文献
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Weibing Guo Zhanlong Yu Zhijie Ding Wenshan Bian Haitao Xue Anhang Li Yiren Hu Chong Fan 《International Journal of Applied Ceramic Technology》2023,20(4):2610-2619
Aluminum nitride (AlN) ceramics and oxygen-free Cu were brazed with multilayer filler consisted of Ag-Cu-Ti +Ni foam. The microstructure and forming principle of AlN/Cu joints were studied and the influence of Ni foam on the joints was focused. The result shows that the composition of AlN/Cu joint was AlN/TiN/Ni3Ti+Cu(s,s)+CuTi+Ni foam+Ag(s,s)/Cu. The joint strength was only 66.7 ± 3.7MPa with pure Ag-Cu-Ti solder and the fracture occurred inside AlN ceramics due to the residual stress. The foam nickel reacted with Ag-Cu-Ti filler metal to form Ni3Ti during brazing process. Ni foam still retained the basic skeleton structure during brazing, and the mechanical capacity of AlN/Cu joint was enhanced significantly. The maximum shear strength of the brazed joint can reach 89.6 ± 4.5 MPa with .1 mm Ni foam, and the fracture position changed to the brazing filler. The result shows that nickel foam can reduce the residual thermal stress, and the mechanical properties of AlN/Cu joints were improved. 相似文献
12.
J. Ba X.H. Zheng R. Ning J.H. Lin J.L. Qi J. Cao W. Cai J.C. Feng 《Journal of the European Ceramic Society》2019,39(4):755-761
Brazing C/SiC composites to Ti6Al4V alloy is associated with the problem of high residual stress inducing low joining strength. To overcome this problem, negative thermal expansion Zr2P2WO12 (ZWP) nanoparticles were introduced into AgCu brazing alloy to obtain robust C/SiC-Ti6Al4V joints. Microstructures and mechanical properties of the joints brazed with different ZWP contents were investigated. Results indicated that 3 wt% ZWP nanoparticles dispersed homogeneously among brazing seam and compatible with brazing alloy. The width of reaction layer at C/SiC side was reduced sharply. Meanwhile, the finite element analysis showed that residual stress was reduced by 52.9 MPa and stress concentration among reaction layer was eliminated. The average shear strength of the joints brazed with AgCu + 3 wt% ZWP increased to 146.2 MPa, which was 70.8% higher than that of joints brazed without ZWP. 相似文献
13.
《Journal of the European Ceramic Society》2021,41(15):7533-7542
In order to meet the sealing demands of SiC heat exchanger, the Ni-Mo filler alloy was designed, prepared and employed to braze SiC ceramics. Wetting behavior of the Ni-Mo filler alloy on SiC ceramics and interfacial microstructure of the brazed joints were systematically characterized using optical observation furnace and XRD, SEM, EDS, TEM, respectively. Flexural strengths of the brazed joints at room temperature and high temperature were measured with four-point flexural strength method. HCl immersion test was performed to evaluate the corrosion resistance of the joints. The Ni-Mo filler alloy exhibited excellent wettability on SiC ceramics. During the process of brazing, SiC reacted with element Ni of the Ni-Mo filler alloy, resulting in the formation of Ni2Si + graphite reaction layer adjacent to the SiC substrate. Ni3Mo3C and Ni2Si compounds were precipitated at the center of brazing seam. When the brazing temperature increased from 1250 ℃ to 1400 ℃, the thickness of Ni2Si + graphite layer increased gradually. The maximum room-temperature flexural strength of 174 ± 33 MPa was obtained when brazed at 1300 ℃ for 40 min. The joints also exhibited stable high-temperature strength and acid corrosion resistance. When the test temperature was 700 ℃, 800 ℃, 900 ℃, the joints gave the strength retention rate of 92.5 %, 79.8 %, 67.2 %, respectively. It was believed that the formation of high melting point phases played an important role. Residual strength of the joints after HCl corrosion exceeded 130 MPa, revealing a good potential for applications in corrosion environment. 相似文献
14.
《Ceramics International》2017,43(17):15296-15305
Residual stresses in ceramic-metal joints is the important factor for their reliable implementation in cutting-edge industries. Composite fillers is reported to be a promising approach to reduce the residual stresses. Until now, few experimental researches on the brazing of ZrO2 ceramic and TC4 alloy using composite fillers have been reported. In this study, to release the residual stresses and improve the joints strength, novel WB reinforced Ag-Cu composite filler was fabricated to braze ZrO2 ceramic and TC4 alloy. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM) were applied for the analysis of microstructure and phases structure in the joints. The TiB whiskers and W particles were in situ synthesized via the reaction between active Ti and WB particles, and randomly distributed in the brazing seam. The effect of brazing temperature and WB content on interfacial microstructure and mechanical strength in the brazed joints were investigated. When brazed at 870 °C for 10 min, favorable microstructure reinforced by TiB whiskers and W particles in the brazing seam was achieved with 7.5 wt% WB addition in composite filler. The maximum average shear strength of the joints was 83.2 MPa, which about 59.4% increase over the joints without WB addition. 相似文献
15.
对壁厚(10+2)mm的L450/316L复合管进行了对焊试验,打底焊及过渡焊采用管内外充氩保护的GTAW焊,填充及盖面焊采用手工电弧焊,并对其焊接接头进行拉伸、刻槽锤断、弯曲、冲击、晶间腐蚀试验评价对焊焊缝的性能,采用光学、扫描电镜(SEM)及能谱分析(EDS)对焊接接头的冲击断口、显微组织及合金元素的进行扩散分析。试验结果表明:接头力学性能良好,耐晶间腐蚀性能较好;焊缝不锈钢层主要有奥氏体、铁素体组成;过渡层组织较细小,可以防止不锈钢层金属中合金元素被扩散层稀释;扩散层组织主要为马氏体、少量的残余奥氏体;合金钢层组织为先共析铁素体、针状铁素体、粒状贝氏体和及少量珠光体。 相似文献
16.
Mechanical behavior of SiC joints brazed using an active Ag‐Cu‐In‐Ti braze at elevated temperatures
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Frank Moszner Gustavo Mata‐Osoro Mirco Chiodi Jolanta Janczak‐Rusch Gurdial Blugan Jakob Kuebler 《International Journal of Applied Ceramic Technology》2017,14(4):703-711
The behavior of SiC ceramic joints brazed with commercially available Incusil ABA (Ag‐32.25Cu‐12.5In‐1.25Ti, in wt.%) was characterized especially with respect to the mechanical performance at temperatures up to 550°C using four‐point bending and torsional shear tests. The failure mechanisms with changing temperature were investigated with the aid of fractography. Additionally, the microstructure of brazed specimens was characterized in detail by high resolution scanning electron microscopy. The test geometry and setup for the high temperature torsional shear test is presented. The change in mechanical behavior of the joints as a function of temperature is shown and discussed. The brazed joints interestingly showed that flexural bending strength was maintained with only a small decrease up to 300°C. Above 300°C, the bending strength decreased much faster. For the first time, this joint system was characterized in torsional shear test at temperatures up to 550°C to achieve the intrinsic shear strength values. Very strong joints were achieved, resulting in failure through the ceramic base materials up to (torsional shear) testing temperatures of 400°C. The results indicate that SiC joints brazed with Incusil ABA exhibit excellent mechanical performance for applications up to 300°C. 相似文献
17.
《Ceramics International》2016,42(6):7080-7087
An Ag–Cu–Ti+TiNp/Cu/Ag–Cu three-layered filler was designed to braze Si3N4 ceramic and Invar alloy. The effect of the Cu-foil thickness on the microstructure and the mechanical properties of the brazed joints was investigated. Compared with single-layer Ag–Cu–Ti+TiNp filler, the formation of Fe2Ti and Ni3Ti compounds is widely inhibited by using multi-layered filler. The shear strength of the brazed joint is 47.9% higher than that of joints brazed with single Ag–Cu–Ti+TiNp filler when a 200 μm thick Cu interlayer is used. A simplified unit cell model was designed to obtain the physical properties of the TiNp reinforced filler. The model provides the elastic modulus and yield stress that satisfy the Hashin–Shtrikman bounds and N. Ramakrishnan׳s equations, respectively. In the three-layered brazing, the finite element (FE) model shows that system residual stresses decrease significantly by increasing the thickness of Cu foil in the multi-layered system. 相似文献
18.
《Ceramics International》2019,45(11):13979-13987
Silicon nitride (Si3N4) ceramic and Invar alloy have been brazed by using AgCuTi active filler and the Ni foam was added to further improve mechanical properties of joints in this study. The microstructure of Si3N4/Invar brazed joint changed obviously after adding Ni foam with different thickness. Ni foam reacted with the AgCuTi active filler during brazing, but it did not completely disappear and still maintained the basic frame structure after brazing. The average shear strength of the brazed joints with 0.2 mm Ni foam could reach 180 MPa, and their thermal cycle lifetime also improved significantly. The addition of Ni foam shifted the fracture location of joints from Si3N4 ceramic to brazing seam. These results indicated that the Ni foam could act as a buffer layer to reduce the residual thermal stress, and improve the mechanical properties of Si3N4/Invar joint. 相似文献
19.
The influence of gradient materials (GM) filler alloy on the distribution of thermal stresses and on the bending strength of the brazed Si3N4–42CrMo steel joints was examined by using finite element modeling (FEM) computations in combination with experiments. In order to form a smooth thermal expansivity change across the whole joint, a novel GM filler alloy was fabricated by stacking each layer with different content of Mo particles (Ag–Cu–Ti+Mo) addition together. We examined the effect of GM compositions, layer numbers and thicknesses on the residual stresses in the brazed joint. In particular, the monolayer composite filler produced by incorporating 10 vol% Mo particles induced the minimum residual stresses in the joint, agreeing with the experimental results. The results indicated that the CTE mismatch between the joined materials and the ability of plastic deformation in the filler alloy were two factors that determine the residual stresses level in a brazed joint. The results reported here will provide us guidance to choose an appropriate filler alloy for improving the ceramic–metal joint performance. 相似文献
20.
《Journal of the European Ceramic Society》2021,41(13):6319-6329
The residual-stress induced failure of Ti-6Al-4V/Si3N4 joints brazed with two different Si3N4 ceramics possessing different intrinsic properties was elucidated through experimental and finite-element (FE) thermo-mechanical simulations incorporating the local elasto-plastic properties of the as-received Ag-Cu-Ti filler and the brazing zone characterized by nano-indentation. All tested joints fractured mainly from the ceramics due to residual stress, and their bending strengths increased when using Si3N4 ceramics of higher intrinsic strength. FE-analysis based on the as-received filler’s properties overestimated the nominal bending strengths by approximately 100 MPa in both joints; nano-indentation revealed that the depletion of ductile Ag-Cu phase and growth of hard Cu-Ti intermetallic compounds reduced the plastically deformable thickness after being brazed, whereby they resulted in higher residual stress in the ceramics. Finally, the validity of FE-estimated bending strengths was enhanced when considering the effective plastically deformable thickness of filler (30 μm) instead of the as-received state (50 μm). 相似文献