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1.
《Ceramics International》2022,48(4):4484-4496
Ti3SiC2 ceramic and SUS430 stainless steel (SS) were successfully joined by a solid diffusion bonding technique using Ni interlayers. Diffusion bonding was performed in the temperature range of 850 °C–1100 °C under vacuum. The interfacial reaction phase, morphology evolution, growth kinetics and tensile strength were systematically investigated. In all cases, the inter-diffusion and reaction between Ti3SiC2 and SS can be effectively prevented by Ni foil, and the good transition in the joint benefit to the sound joining. The interface in the joints adjacent to SS matrix was composed of γ solid solution and a small amount of σ intermetallic compound. The compounds in the Ni/Ti3SiC2 interface was Ni/Ni(Si)/Ni31Si12 + Ni16Ti6Si7 + Ti3SiC2 + TiCx/Ti2Ni + Ti3SiC2 + TiCx/Ti3SiC2, which formed by the inter-diffusion and chemical reactions between Si and Ni atoms. The diffusion mechanism and reaction mechanism were interrelated, and decided the width of each reaction zones. Furthermore, the diffusion activation energy was 113 kJ/mol. The tensile strength increases with increasing the bonding temperature. The minimum and maximum strength of 32.3 MPa and 88.8 MPa were obtained from SUS430/Ni/Ti3SiC2 joints, which bonding experiments were carried out at 850 °C and 1100 °C, respectively.  相似文献   

2.
Reliable contact-reactive brazed joints of TC4 alloy and Ti3SiC2 ceramic were obtained using a Cu interlayer. The interfacial microstructure of a TC4/Ti3SiC2 joint brazed at 920?°C for 10?min was TC4/Ti2Cu +?α-Ti +?β-Ti/Ti2Cu +?AlCu2Ti +?Ti5Si3/Ti5Si3 +?Ti5Si4/Ti3SiC2. The interfacial microstructure and mechanical properties of TC4/Ti3SiC2 joints brazed at different temperatures were investigated. With increasing temperature, the shear strength of the brazed joints first increased and then decreased. The maximum shear strength was 132?±?8?MPa, and the corresponding fracture occurred along the Ti–Si reaction layer and the Ti3SiC2 substrate adjacent to the Ti–Si reaction layer. The microhardness test also demonstrated that the Ti–Si reaction layer possessed the highest microhardness, 812?±?22 HV. The Ti-Si reaction layer was the weakest part of the brazed joints. To eliminate the Ti-Si reaction layer and improve the mechanical properties of TC4/Ti3SiC2 brazed joints, a 40-μm Ni layer was plated on the surface of the Ti3SiC2 ceramic before brazing. The results showed that the Ti–Si reaction layer that formed adjacent to the Ti3SiC2 ceramic was thin and intermittent. Moreover, the interface between the Ti3SiC2 ceramic and the TC4 alloy became jagged. The shear strength of the TC4/nickel-plated Ti3SiC2 brazed joints improved to 148?±?8?MPa; the corresponding fracture occurred mainly in the Ti3SiC2 ceramic and only a small portion of the fracture occurred in the brazing seam.  相似文献   

3.
In the present study, diffusion bonding of two dissimilar materials TC6 and copper alloy was investigated in vacuum chamber by directly bonding and using Ni foil as interlayer. Interface quality of the joints was evaluated by mechanical property and microstructure. The maximum shear strength of directly bonding was found to be 64 MPa for the speciemen bonded at 850 °C, 5 MPa for 30 min; and the maximum shear strength with Ni foil interlayer was 113 MPa under the same bonding parameters. The bonding interfaces and fracture surfaces were analyzed by energy disperse spectrometer, scanning electron microscopy and X-ray diffraction. The results show that the diffusion region of directly bonding specimen generated several IMCs (Ti2Cu and Ti5CuSn3, etc.). Fracture morphology showed that brittle fracture present at the Ti5CuSn3 IMCs, which was the weak point of the joint. While the diffusion zone of the specimen with Ni foil interlayer consists of various phase including Ti2Ni, TiNi, TiNi3 at TC6 side, and Cu-Ni solid solution at ZQSn11-4-3 side, and fracture surface of joint present a mixture of brittle and ductile characteristics, and fracture initiated at the TiNi3/Ni interface.  相似文献   

4.
Based on the structure characteristic of Ti3SiC2 and the easy formation of Ti3Si1−xAlxC2 solid solution, a transient liquid phase (TLP) bonding method was used for bonding layered ternary Ti3SiC2 ceramic via Al interlayer. Joining was performed at 1100–1500 °C for 120 min under a 5 MPa load in Ar atmosphere. SEM and XRD analyses revealed that Ti3Si(Al)C2 solid solution rather than intermetallic compounds formed at the interface. The mechanism of bonding is attributed to aluminum diffusing into the Ti3SiC2. The strength of joints was evaluated by three point bending test. The maximum flexural strength reaches a value of 263 ± 16 MPa, which is about 65% of that of Ti3SiC2; for the sample prepared under the joining condition of 1500 °C for 120 min under 5 MPa. This flexural strength of the joint is sustained up to 1000 °C.  相似文献   

5.
Porous Si3N4 (P–Si3N4) ceramic was successfully joined to Invar alloy using a Cu–Ti active brazing alloy for the first time. The interfacial reactions between the Cu–Ti filler and two dissimilar substrates were studied. The influence of brazing process on the microstructure evolution of the joint was revealed, along with the formation of an infiltration layer that permitted the bonding of P–Si3N4 substrate. Ti reacted with Si3N4 to form TiN and Ti5Si3 compounds, resulting in the decomposition of Si3N4. In addition, the reaction and diffusion dual-layer formed at the Cu–Ti/Invar interface, which was attributed to the interaction of alloy elements between the braze filler and the Invar alloy. Fe–Ti and Ni–Ti intermetallics together with Cu solid solution (s,s) constituted the microstructure of the brazing seam. In addition, the optimal shear strength of the brazed joint was 20 MPa and the fracture propagation occurred in the P–Si3N4 ceramic substrate adjacent to the infiltration layer during the shearing tests.  相似文献   

6.
In this study, diffusion bonding of WC-Co cemented carbides to a tool steel was realized utilizing Ni foils as the interlayer in a vacuum. The effects of bonding temperature and Ni interlayer thickness on interfacial microstructure and mechanical properties of the joint were studied. The research results revealed that brittle phases and cracks were suppressed due to the Ni interlayer. Moreover, the coherent relationship of [1 2 0]WC//[1 0 1]Ni and (0 0 1)WC//(0 2 0)Ni was observed at the interface of WC grains and Ni interlayer, and it greatly contributed to the bonding strength of WC-Co/steel joint. As the bonding temperature increased, the atoms diffused sufficiently, and the interfacial defect dimensions decreased. Then, the Ni interlayer was transferred to solid solutions, resulting in the high shear strength of the bonded joint. The optimum shear strength (444.7 MPa) was achieved when the bonding was carried out at 1050 °C for 1 h with a 4-μm-thick Ni interlayer. The cracks were propagated in the interlayer and the WC-Co substrate near the bonding seam.  相似文献   

7.
《Ceramics International》2017,43(11):8126-8132
A novel composite interlayer with a reinforced network was designed using a SiC ceramic with a network structure and Ti-Ni-Nb composite filler foils, to which the Nb and BN-SiO2 ceramic were successfully brazed under vacuum. For a brazing temperature of 1160 °C and holding time of 10 min, the interfacial microstructure of the Nb/BN-SiO2 ceramic joint was Nb/(βTi,Nb)-TiNi eutectic structure+(βTi,Nb)2Ni+SiC+TiC/TiN+Ti2N+TiB+Ti5Si3+TiO/BN-SiO2 ceramic. In addition, the shear strength and nano-hardness were analyzed to evaluate the effect of the composite interlayer with a network reinforcement architecture on the mechanical properties of the joint. During brazing, the Ti-Ni-Nb filler metal infiltrated and reacted with the SiC to form the network reinforcement architecture, resulting in the residual stress being relieved and the mechanical performance of the joint being significantly improved. A maximum shear strength of 102 MPa was achieved, which was 60 MPa (142%) higher than that of the joint brazed without the network reinforcement architecture. A reduction in the residual stress on the BN-SiO2 ceramic side from 328 MPa to 210 MPa was observed with the network reinforcement architecture, and the fracture path of the joint changed from the surface of the BN-SiO2 ceramic to the interfacial reaction zone.  相似文献   

8.
Monolithic high purity CVD β-SiC materials were successfully joined with a pre-sintered Ti3SiC2 foil via solid-state diffusion bonding. The initial bending strength of the joints (∼ 220 MPa) did not deteriorate at 1000 °C in vacuum, and the joints retained ∼ 68 % of their initial strength at 1200 °C. Damage accumulation in the interlayer and some plastic deformation of the large Ti3SiC2 grains were found after testing. The activation energy of the creep deformation in the temperature range of 1000 – 1200 °C in vacuum was ∼ 521 kJmol−1. During the creep, the linkage of a significant number of microcracks to form a major crack was observed in the interlayer. The Ti3SiC2 interlayer did not decompose up to 1300 °C in vacuum. A mild and well-localized decomposition of Ti3SiC2 to TiCx was found on the top surface of the interlayer after the bending test at 1400 °C in vacuum, while the inner part remained intact.  相似文献   

9.
《Ceramics International》2017,43(5):4151-4158
In this paper, a novel brazing process based on in-situ alloying concept was carried out to join Cf/SiC composite to TC4 alloy at 940 °C for 20 min. Mixed powders of Ti-Zr-Cu-Ni alloy and pure Ti metal were used as interlayer. In the process, Ti-Zr-Cu-Ni alloy melted and then dissolved pure Ti metal via liquid-solid reactions, achieving in-situ alloying of the interlayer. The interfacial microstructure and formation mechanism of the brazed joints were investigated. The effect of Ti powder content on the microstructure and the mechanical properties of joints were analyzed. The results showed that: the maximum lap-shear strength of the in-situ alloying brazed joints was 283±11 MPa when using (Ti-Zr-Cu-Ni)+40 vol% Ti composite filler, and this value was 79% higher than the mechanical strength when using Ti-Zr-Cu-Ni alone. A reaction layer of (Ti,Zr)C+Ti5Si3 formed near Cf/SiC composite side, while a diffusion layer of Ti2Cu+Ti(s,s) formed near Ti-6Al-4V side. In the interlayer, lots of Ti(s,s) were distributed uniformly and few of Ti-Cu compounds were found, contributing to the plasticity of joints. Adding moderate Ti powder was beneficial for improving the interfacial reaction between Cf/SiC composite and filler material, which affected the lap-shear strength of joints.  相似文献   

10.
Reducing the residual stresses and improving the mechanical strength of large-scale ceramic/metal brazing joints is an important problem that must be solved for its practical engineering application. Using composite filler with solid-state phase transformation ceramic particulates, it is theoretically feasible to relieve the residual stress and improve the mechanical properties of ceramic/metal brazed joints. In this study, Cu mesh, Ag–28Cu–2Ti (wt.%), and yttria-stabilized zirconia (0.6 mol.% YSZ solid-state phase transformation ceramic particulates) composite power fillers were used in the brazing of Ti3SiC2 ceramic and pure copper. The microstructure of joints and YSZ particulates in the interface was investigated and confirmed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), scanning transmission electron microscopy (STEM), and transmission electron microscopy (TEM). In addition, the effect of YSZ particulates content on the mechanical properties of joints was investigated and evaluated by the shear strength. The results show that the interfacial phases were mainly Ti5Si3, TiC, TixCu, Ag (s, s), Cu (s, s), and YSZ particulates. Moreover, most of YSZ particulates undergo the solid-state phase transformation from tetragonal zirconia (t-ZrO2) to monoclinic zirconia (m-ZrO2) during the cooling process of brazing. The abnormal volume expansion of the solid-state phase transformation reduced the thermal mismatch between Ti3SiC2 ceramic and filler, thereby reducing the residual stress in the interface of joint. When using composite filler with 6 wt.% YSZ particulates, the shear strength of Ti3SiC2/Cu joint reached the maximum. The maximum average shear strength of the joints was 80.2 MPa, which was about 103.6% more than the joint without YSZ particulates.  相似文献   

11.
The Si3N4 ceramic was brazed by Ag–Cu–Ti + SiCp composite filler (p = particle) prepared by mechanical mixing. Effects of the content of Ti and SiC particles on microstructure of the joint were investigated. A reliable Si3N4/Si3N4 joint was achieved by using Ag–Cu–Ti + SiCp composite filler at 1173 K for 10 min. A continuous and compact reaction layer, with a suitable thickness, forms at the Si3N4/braze interface. The SiC particles react with Ti in the brazing layers, forming Ti3SiC2 thin layers around the SiC particles themselves and Ti5Si3 small particles in the Ag[Cu] and Cu[Ag] based solid solution. The higher content of SiC particles in the filler (≥10 vol%) depresses interfacial bonding strength between the Si3N4 substrate and composite brazing layer due to the thinner reaction layer and the bad fluidity of the filler. The Ti3SiC2 → TiC + Ti5Si3 reaction occurs when Ti concentration around SiC particles in the filler increases.  相似文献   

12.
To prepare large-sized and complex-shaped components, the feasibility of direct diffusion bonding of (Hf0.2Zr0.2Ti0.2Ta0.2Nb0.2)C high-entropy ceramic (HEC) and its diffusion bonding with a metallic Ni foil was investigated, and the interfacial microstructure and mechanical properties of HEC/HEC and HEC/Ni/HEC joints were analyzed. For the direct diffusion bonding, reliable joints with a shear strength of 146 MPa could be achieved when the bonding temperature reached 1500 °C under a pressure of 30 MPa. By introducing a metallic Ni foil as the interlayer, the HEC was successfully bonded at the diffusion temperatures from 1150 °C to 1250 °C under 10 MPa through the formation of Ti2Ni compound phase. Meanwhile, the HEC(Ni) phase formed by the diffusion of Ni into HEC and Ni(s, s) bulks precipitated in the bonding transition zone. The maximum joint shear strength of 151 MPa was obtained by optimizing the Ni-foil thickness, bonding temperature, and holding time.  相似文献   

13.
A robust solid state diffusion joining technique for SiC ceramics was designed with a thickness-controlled Ti interlayer formed by physical vapor deposition and joined by electric field-assisted sintering technology. The interface reaction and phase revolution process were investigated in terms of the equilibrium phase diagram and the concentration-dependent potential diagram of the Ti-Si-C ternary system. Interestingly, under the same joining conditions (fixed temperature and annealing duration), the thickness of the Ti interlayer determined the concentration and distribution of the Si and C reactants in the resulting joint layer, and the respective diffusion distance of Si and C into the Ti interlayer differentiated dramatically during the short joining process (only 5 min). In the case of a 100 nm Ti coating as an interlayer, the C concentration in the joint layer was saturated quickly, which benefited the formation of a TiC phase and subsequent Ti3SiC2 phase. The SiC ceramics were successfully joined at a low temperature of 1000 °C with a flexural strength of 168.2 MPa, which satisfies applications in corrosive environments. When the Ti thickness was increased to 1 μm, Si atoms diffused easily through the diluted Ti-C alloy (a dense TiC phase was not formed), and the Ti5Si3 brittle phase formed preferentially. These findings highlight the importance of the diffusion kinetics of the reactants on the final composition in the solid state reaction, particularly in the joining technique for covalent SiC ceramics.  相似文献   

14.
《Ceramics International》2021,47(23):32545-32553
Wetting and interfacial behavior of molten Al-(10, 20, 30, 40) at.%Ti alloys on C-terminated 4H–SiC at 1500 and 1550 °C were investigated experimentally, and theoretical bonding strength, structure stability and electronic structure of interfacial reaction products/C-terminated 4H–SiC interfaces were evaluated by first-principle calculations. The wetting experiments show that the Al–Ti/SiC systems present excellent wettability with contact angle of less than 15° except the Al–40Ti/SiC system performed at 1500 °C × 30 min. The SEM-EDS and TEM analyses demonstrate that the reaction products are mainly composed of Al4C3, TiC, Ti3SiC2, Ti5Si3CX and τ phase, and their formation and evolution can be mainly affected by the Ti concentration in the Al–Ti alloys and wetting temperature. Moreover, the calculated results show that the SiC/C-terminated TiC interface presents the highest work of separation and its electronic property reveals that the localization of electrons and formation of covalent bond between interfacial C atoms lead to the excellent bonding strength of SiC/TiC interface.  相似文献   

15.
《Ceramics International》2020,46(5):5937-5945
SiC whisker coating was prepared on the surface of C/C composite successfully by CVD, and transient liquid phase (TLP) diffusion bonding was employed to realize the joining of SiC whisker coating modified C/C composite and Ti2AlNb alloy using Ti–Ni–Nb foils as interlayer. The microstructure, shear strength and fracture behavior were investigated by scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDS), X-ray diffraction (XRD) and universal testing machine. The results show that SiC has good compatibility with C/C composite, and gradient interface formed between SiC-modified C/C composite and Ti2AlNb alloy. When the bonding experiment was carried out under bonding temperature of 1040 °C and holding time of 30min with 5 MPa pressure in vacuum, the joints formed well and no obvious defects can be observed. The typical microstructure of joints is C/C composite/SiC + TiC/Ti–Ni compounds + Ti–Ni–Nb solid solutions/residual Nb/diffusion reaction layer/Ti2AlNb alloy. With the increasing of bonding temperature, the thickness of joining area increased due to sufficient element diffusion. However, when bonding temperature is elevated to 1060 °C, some defects such as cracks and slag inclusions exist in the interface layer between interlayer and Ti2AlNb. The joints with maximum average shear strength of 32.06 MPa are bonded at 1040 °C for 30min. C, SiC and TiC can be found on the fracture surface of joints bonded at 1040 °C which indicated that fracture occurred at the interface layer adjacent SiC layer.  相似文献   

16.
The SiCf/Si3N4 composite with low–high–low permittivity sandwich structure was designed for high-temperature electromagnetic (EM) wave absorption and mechanical stability. The SiCf/Si3N4 possessed the remarkable mechanical properties at room temperature (the flexural strength is 357 ± 16 MPa and the fracture toughness is 10.8 ± 1.7 MPa m1/2) for the strong fiber strength, moderate interface bonding strength and uniform matrix. Furthermore, the retention rate is as high as 80% at 800 °C. The A/B/C nanostructure and the sandwich meta-structure endowed the SiCf/Si3N4 with an excellent EM absorbing property at room temperature. The SiCf/Si3N4 still absorbed 75% of the incident EM waves energy in X and Ku bands when the temperature increases up to 600 °C, which is only 6% lower than that at room temperature, for the partial compensation of the decreased interfacial polarization loss for the increased conductivity loss and dipole polarization loss.  相似文献   

17.
《Ceramics International》2022,48(13):18551-18557
In this study, Al2O3 ceramic and Cu bars were brazed with newly designed Ag–Cu–Ti(ABA)+Zn composite fillers. Systematic analysis of the microstructure of the brazed joints indicated that the volatilization of Zn atoms during the brazing process could promote the spreading of liquid brazing fillers on the surface of the Al2O3 ceramic, resulting in a uniform dendritic interfacial structure. The typical interfacial structure was an Al2O3/TiO/(Cu, Al)3Ti3O+Ag(s, s)/Cu interface. Notably, the tensile strength was improved to 20.89 MPa for Al2O3/Cu joint brazed with ABA+Zn composite fillers at 900 °C for 20 min, approximately 67.6% higher than the sample brazed without Zn foil. In this case, the fracture model was straight and sharp-angled inside the Al2O3 ceramic. In addition, the joint strength decreased with increased brazing temperatures from 900 to 940 °C.  相似文献   

18.
The Si3N4 ceramic was joined to 42CrMo steel using Ag–Cu–Ti + Mo composite filler. Effect of Mo particles content on the microstructure and mechanical properties of the joints were investigated. Defect-free joints were received when the Si3N4/42CrMo steel joints were brazed with Ag–Cu–Ti + Mo composite filler. The results show that a continuous reaction layer which is composed of TiN and Ti5Si3 was formed near the Si3N4 ceramic. A double reaction layer which consists of Fe2Ti and FeTi was also formed adjacent to 42CrMo steel, with Fe2Ti being located near the steel. The central part of the joint is composed of Ag based solid solution, Cu based solid solution, Mo particles and some Cu–Ti intermetallic compounds. The maximal bending strength reached 587.3 MPa with 10 vol.% Mo particles in the joint, at which the joint strength was 414.3% higher than the average strength for the case without Mo particles addition.  相似文献   

19.
Owing to the good physicochemical compatibility and complementary mechanical properties of Ti3SiC2 and Al2O3, Ti3SiC2/Al2O3 composites are considered as ideal structural materials. However, TiC and TiSi2 typically coexist during the synthesis of Ti3SiC2/Al2O3 composites through an in-situ reaction, which adversely affects the mechanical properties of the resulting composites. In this study, Ti3SiC2/Al2O3 composites were prepared via in-situ hot pressing sintering at 1450 °C. Ge, which was used as a sintering aid, improved the purity and mechanical properties of the Ti3SiC2/Al2O3 composites. This is because Ge replaced some of the Si atoms to compensate the evaporation loss of Si to form Ti3(Si1-xGex)C2, which showed a crystal structure similar to that of Ti3SiC2. Furthermore, the molten Ge accelerated the diffusion reaction of the raw materials, increasing the overall density of the Ti3SiC2/Al2O3 composites. The optimum Ge amount for improving the mechanical properties of the composites was found to be 0.3 mol. The flexural strength, fracture toughness, and microhardness of the composite with the optimum Ge amount were 640.2 MPa, 6.57 MPa m1/2, and 16.21 GPa, respectively. The formation of Ti3(Si1-xGex)C2 was confirmed by carrying out X-ray diffraction, energy dispersive spectroscopy, and transmission electron microscopy analyses. A model crystal structure of Ti3(Si1-xGex)C2 doped with 0.3 mol Ge was established by calculating the solid solubility of Ge.  相似文献   

20.
SiC-coated 3D C/SiC composites were successfully joined using SPS technology with a Ti-Si-C interlayer. The interface morphologies, phase composition, and mechanical properties of the joints were investigated in detail. By adjusting the joining temperature, the interlayer transitioned, in situ, from Ti-Si-C compounds to Ti3SiC2 grains without decomposition. Because of the plastic deformation behavior of Ti3SiC2 grains, the ability of the interlayer to inhibit crack propagation increased. For joints with different interlayer thickness, the distribution of thermal residual stress was calculated using finite element analysis, and the distribution was associated with the evolution of interlayer morphologies, which was eventually used to establish fracture models. Optimized bonding was achieved without erosion of carbon fibers and also without interfacial defects. Finally, a reliable joint with shear strength of 51 ± 3.0 MPa was obtained by precisely controlling the interlayer reaction and optimizing thermal residual stress.  相似文献   

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