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1.
Diffusion bonding of Zircaloy-4 and Type 316-L stainless steel was carried out by coating the joining surfaces with Ti to minimize the interlayer effect. Bonding heat treatments were carried out in vacuum at 1000 °C for 4 h and 1050 °C for 1 h. The microstructure of the diffusion zone was investigated by scanning electron microscopy and the phases in the diffusion zone were analyzed by energy dispersive spectroscopy. It is observed that Ti coating at the interface produced a dendritic structure in the diffusion zone formed in the Zircaloy-4. The concentration of the dendrites increases with an increase in bonding temperature. 相似文献
2.
Adnan Çal?k 《Materials Letters》2009,63(28):2462-2465
The diffusion bonding of a Ni3Al intermetallic alloy to an austenitic stainless steel has been carried out at temperatures 950, 1000 and 1050 °C. The influence of bonding temperature on the microstructural development and hardness across the joint region has been determined. The microvoids in the interface have been found to decrease with increasing bonding temperature. The intermetallic phase Al3Ni has been detected at the Ni3Al side of the diffusion couple. Diffusion of Cr and Fe from the stainless steel to the Ni3Al alloy has been observed. 相似文献
3.
A functionally graded WC–Co/Ni composite (FGWC) and 410 stainless steel (410ss) were successfully bonded by diffusion bonding. With the bonding temperature or holding time increasing, the tensile strength of the joints increased firstly and then decreased. The maximum tensile strength of the FGWC/410ss joints was 195 MPa bonded at 950 °C for 80 min. A diffusion layer was formed between the Ni layer and the 410ss as a result of the interdiffusion of Ni and Fe. The Ni layer could release the residual stresses of the FGWC/410ss joints. The fracture of the FGWC/410ss joints occurred in the Ni layer by the way of ductile fracture. 相似文献
4.
Microstructure and mechanical properties of diffusion bonded SiC/steel joint using W/Ni interlayer 总被引:1,自引:0,他引:1
This paper describes the design and examination of W/Ni double interlayer to produce a joint between SiC and ferritic stainless steel. Diffusion bonding was performed by a two steps solid state diffusion bonding process. Microstructural examination and mechanical properties evaluation of the joints show that bonding of SiC to steel was successful. EDS and XRD analysis revealed that W5Si3 and WC were formed at SiC/W interface. The diffusion products at W/Ni interface, Ni-rich solid solution Ni(W) or intermetallic compound Ni4W, was found to be dependent on the second step joining temperature. Neither intermediate phases nor reaction products was observed at Ni/steel interface for the joints bonded at the temperature studied. The average tensile strength of 55 MPa which is insensitive to the second step process was measured for as-bonded SiC/steel joint and the failure occurred at SiC/W interface. The hardness near the various bonded interfaces was also evaluated. 相似文献
5.
The differences in physical and metallurgical properties of stainless steels and magnesium alloys make them difficult to join using conventional fusion welding processes. Therefore, the diffusion brazing of 316L steel to magnesium alloy (AZ31) was performed using a double stage bonding process. To join these dissimilar alloys, the solid-state diffusion bonding of 316L steel to a Ni interlayer was carried out at 900 °C followed by diffusion brazing to AZ31 at 510 °C. Metallographic and compositional analyses show that a metallurgical bond was achieved with a shear strength of 54 MPa. However, during the diffusion brazing stage B2 intermetallic compounds form within the joint and these intermetallics are pushed ahead of the solid/liquid interface during isothermal solidification of the joint. These intermetallics had a detrimental effect on joint strengths when the joint was held at the diffusion brazing temperature for longer than 20 min. 相似文献
6.
Interface structure of diffusion bonded duplex stainless steel and medium carbon steel couple 总被引:2,自引:0,他引:2
Diffusion bonding of duplex stainless steel to medium carbon steel was carried out with different temperatures for sound bonds. In the bonding process, relatively intermediate temperatures such as 750, 800, 850 and 900 °C were used with a bonding time of 30 min. In this study, microstructural changes and mechanical properties in the interface region of duplex stainless steel and medium carbon steel couples were determined. The results showed that, in interface region, Cr23C6 was formed on the stainless steel side, while ferrite formation was observed on the carbon steel side as a result of mutual diffusion of C and Cr. 相似文献
7.
The densification and microstructural evolution during co-sintering of M2 tool steel/316L stainless steel composite layers
with and without boron addition was studied. A pressureless sintering method in conjunction with a powder layering technique
was used to fabricate the stepwise graded composite layers. Isothermal and non-isothermal sintering response of the individual
and composite layers was examined and the microstructural features of the bonding zone were studied. Shear strength and microhardness
of the bonding zone were also measured. It was shown that an enhanced densification is obtained in the composite layers due
to (i) sintering shrinkage incompatibility between two steels, (ii) interlayer diffusion of the alloying elements and formation
of a dual δ-ferrite/austenite phase at high temperature, and (iii) formation of a low temperature eutectic Fe (C)-B phase
at the interface in the samples containing boron. The morphology of carbides in M2/316L is significantly changed as the sintering
temperature increases, i.e., they appeared as fine intergranular carbides at low temperatures (1,240 °C), thick film at 1,260 °C
and herringbone shape eutectic at 1,290 °C. Elongated grains with an intergranular boride phase were seen in the bonding zone
of M2/316L + B layers. The shear strength of the interface of the composite layers was found to be superior to that of the
individual layers. 相似文献
8.
The solid-state diffusion bonding was carried out between commercially pure titanium and Type 304 stainless steel using nickel
as an interlayer in the temperature range of 800–900 °C for 9 ks under 3 MPa load in vacuum. The transition joints thus formed
were characterized in the optical and scanning electron microscopes. The inter-diffusion of the chemical species across the
diffusion interfaces were evaluated by electron probe microanalysis. TiNi3, TiNi and Ti2Ni are formed at the nickel–titanium (Ni–Ti) interface; however, the stainless steel–nickel (SS–Ni) diffusion interface is
free from intermetallic compounds up to 850 °C temperature. At 900 °C, the Ni–Ti interface exhibits the presence of α-β Ti
discrete islands in the matrix of Ti2Ni and λ + χ + α-Fe, λ + FeTi and λ + FeTi + β-Ti phase mixtures occur at the SS–Ni interface. The occurrence of different
intermetallics are confirmed by the x-ray diffraction technique. The maximum tensile strength of ∼276 MPa and shear strength
of ∼209 MPa along with 7.3% elongation were obtained for the diffusion couple processed at 850 °C. At the 900 °C joining temperature,
the formation of Fe–Ti base intermetallics reduces the bond strength. Evaluation of the fracture surfaces using scanning electron
microscopy and energy dispersive spectroscopy demonstrates that failure takes place through Ni–Ti interface up to 850 °C and
through the SS–Ni interface of the joint when processed at 900 °C. 相似文献
9.
《Materials Science & Technology》2013,29(7):914-918
AbstractVacuum hot roll bonding of titanium alloy and stainless steel using a nickel interlayer was investigated. No obvious reaction or diffusion layer occurs at the interface between stainless steel and nickel. The interface between titanium alloy and nickel consists of an occludent layer and diffusion layers, and there are the intermetallic compounds (TiNi3, TiNi, Ti2Ni and their mixtures) in the layers. The total thickness of intermetallic layers at the interface between titanium alloy and nickel increases with the bonding temperature, and the tensile strength of roll bonded joints decreases with the bonding temperature. The maximum tensile strength of 440·1 MPa was obtained at the bonding temperature of 760°C, the reduction of 20% and the rolling speed of 38 mm s–1. 相似文献
10.
In this study, the microstructure and mechanical properties of sintered AISI 316L stainless steel implant materials produced by powder metallurgy (P/M) method were investigated as a function of porosity amount. AISI 316L stainless steel powders were cold-pressed with 800 MPa pressure and sintered at 1200 °C, 1250 °C and 1300 °C for 30 min in a nitrogen atmosphere. The mechanical properties of the 316L implant samples were determined by tensile, fatigue and microhardness tests. Metallographic studies such as pore formation, and fractured surface analyses were performed by Scanning Electron Microscopy (SEM) and Light Optical Microscopy (LOM). The results of this study indicate that, irregular pore formation tendencies increase with an increase in porosity (%). Furthermore, an increase in porosity was shown to decrease the mechanical properties of sintered AISI 316L stainless steel. Sintering temperature is important parameter in decreasing the porosity of P/M materials. 相似文献
11.
《材料科学技术学报》2019,35(7):1499-1507
Irregular grains, high interfacial stresses and anisotropic properties widely exist in 3D-printed metallic materials, and this paper investigated the effects of heat treatment on the microstructural, mechanical and corrosion properties of 316 L stainless steel fabricated by selective laser melting. Sub-grains and low-angle boundaries exist in the as-received selective laser melted (SLMed) 316 L stainless steel. After heat treatment at 1050 °C, the sub-grains and low-angle boundaries changed slightly, and the stress state and strength decreased to some extent due to the decrease of dislocation density. After heat treatment at 1200 °C, the grains became uniform, and the dislocation cells vanished, which led to a sharp decline in the hardness and strength. However, the ductility was improved after recrystallization heat treatment. The passive film thickness and corrosion potential of the SLMed 316 L stainless steel decreased after heat treatment, and the pitting potential also decreased due to the accelerated transition from metastable to steady-state pitting; this accelerated transition was caused by the presence of weak passive films at the enlarged pores after heat treatment, especially for an adequate solid solution treatment. 相似文献
12.
《Materials Science & Technology》2013,29(2):248-256
AbstractSolid state diffusion bonded joint between titanium and 17-4 precipitation hardening stainless steel was carried out in the temperature range of 800–1050°C in steps of 50°C for 30 min and also at 950°C for 30–180 min in steps of 30 min under a uniaxial pressure of 3·5 MPa in vacuum. Bonded samples were characterised using light microscopy, field emission scanning electron microscopy and X-ray diffraction technique. Up to 850°C for 30 min, FeTi phase was formed at the diffusion interface; however, α-Fe+λ, χ, Fe2Ti and FeTi phases and phase mixtures were formed above 850°C for 30 min and at 950°C for all bonding times. Maximum tensile strength of ~326 MPa, shear strength of ~254 MPa and impact toughness of ~24 J were obtained for the diffusion couple processed at 1000°C for 30 min and 30–180 min time interval at 950°C, and maximum tensile strength ~323 MPa, shear strength ~243 MPa and impact toughness of ~22 J were achieved when bonding was processed for 120 min. The residual stress of the bonded joints increases with the increase in bonding temperatures and times. 相似文献
13.
《Materials at High Temperatures》2013,30(3):198-203
AbstractThe tensile deformation behaviour of 316LN stainless steel was investigated from ambient temperature up to 1000°C. The hardness and microstructure of area near tensile fracture were characterised. The results show that the engineering stress increases smoothly with engineering strain when the tensile temperature is at 400°C or below, while the plastic deformation stage displays a serrated/jerky flow at 600°C. At tensile temperatures of 800°C or above, the plastic deformation stage is dramatically prolonged. The deformation mechanisms of 316LN stainless steel are proposed to be sliding and twinning at 400°C or below, tangle dislocations due to cross-slipping at 600°C, dynamic recovery at 700°C, and dynamic recrystallisation at 800°C or above. The finding provides useful guidelines for the processing and service of 316LN stainless steel components at high temperatures. 相似文献
14.
In the present work, plates of stainless steel (grade 410) were joined to copper ones through a diffusion bonding process using a nickel interlayer at a temperature range of 800–950 °C. The bonding was performed through pressing the specimens under a 12-MPa compression load and a vacuum of 10? 4 torr for 60 min. The results indicated the formation of distinct diffusion zones at both Cu/Ni and Ni/SS interfaces during the diffusion bonding process. The thickness of the reaction layer in both interfaces was increased by raising the processing temperature. The phase constitutions and their related microstructure at the Cu/Ni and Ni/SS diffusion bonding interfaces were studied using optical microscopy, scanning electron microscopy, X-ray diffraction and elemental analyses through energy dispersive spectrometry. The resulted penetration profiles were examined using a calibrated electron probe micro-analyzer. The diffusion transition regions near the Cu/Ni and Ni/SS interfaces consist of a complete solid solution zone and of various phases based on (Fe, Ni), (Fe, Cr, Ni) and (Fe, Cr) chemical systems, respectively. The diffusion-bonded joint processed at 900 °C showed the maximum shear strength of about 145 MPa. The maximum hardness was obtained at the SS–Ni interface with a value of about 432 HV. 相似文献
15.
Characterization of transition joints of commercially pure titanium to 304 stainless steel 总被引:4,自引:0,他引:4
Solid-state direct bonding between commercially pure titanium and type 304 austenitic stainless steel has been carried out in the temperature range of 850–950 °C, under a uniaxial pressure of 3 MPa for 1 h. The diffusion bonds have been evaluated using light microscopy, electron probe microanalysis (EPMA), X-ray diffraction (XRD) technique and tensile testing. Light microscopy shows that different intermediate layers are formed in the reaction zone, and the width of these layers increases with an increase in bonding temperature. EPMA revealed that, at any particular bonding temperature, Ti traverses a minimum distance in the 304 stainless steel side, whereas Fe, Cr and Ni travel comparatively larger distances in the Ti side. This microanalysis also indicated different step formations in the concentration profile of Ti, Fe and Cr over different composition ranges in the diffusion zone indicating formation of intermetallic phases that were detected by XRD. Brittle intermetallic phases lower the strength and ductility of the diffusion bonded couples significantly. Best room temperature tensile strength, 217 MPa, has been obtained at 850 °C processing temperature due to minimal deleterious effects. 相似文献
16.
José Lemus-Ruiz Leonel Ceja-Cárdenas J. A. Verduzco Osvaldo Flores 《Journal of Materials Science》2008,43(18):6296-6300
The objective of this work was to study various aspects of liquid and solid state diffusion bonding of cylindrical samples
of WC (with 6% Co) and commercially pure nickel (99.5%) produced by direct bonding and brazing using a 25 μm thick 70Cu 30Zn (wt%) alloy as joining element. Joining experiments were carried out on WC/Ni and WC/Cu Zn/Ni
combinations at temperature of 980 °C using 1, 15, 25 and 35 min holding times in argon (Ar). The results show that it is
possible to create a successful joint at temperature and times used. Joining occurred by the formation of a diffusion zone.
The joining interface is feasible because it presents a homogeneous interface with no several interfacial cracking and porosity.
In both combinations, it can be observed a diffusion of cobalt decreasing in the direction of the metal, as well as, the diffusion
of nickel decreasing in the direction of the ceramic. 相似文献
17.
《材料与设计》2015
Stainless steel (316) foams of varying porosities have been made through powder metallurgy route using NH4HCO3 as a space holder. Green compacts of stainless steel powder with NH4HCO3 were sintered at two different temperatures: 1100 °C and 1200 °C. At higher sintering temperatures, neighboring stainless steel powders fused together to form polycrystalline grain structure with iron–chromium intermetallic phases segregated along the grain boundaries. Whereas, the fusion of neighboring stainless steel powders was limited around the particle–particle contact only when the green compacts were sintered at 1100 °C, which resulted in a larger amount of microporosities in the cell wall. These foams exhibited strain hardening behavior in the plateau region under compressive loading. The yield stress and the flow stress (at lower strain levels) of foams, sintered at 1100 °C were higher. But, the reverse is true for the flow stress at higher strain levels. The exponents and the coefficients of the power law relationships varied with sintering temperature and strain levels. 相似文献
18.
19.
《Materials Science & Technology》2013,29(1):131-136
AbstractSolid state diffusion bonding was carried out between commercially pure titanium and 304 stainless steel in the temperature range 800 - 950°C for 120 min in vacuum under uniaxial load. The transition joints were characterised using optical and scanning electron microscopy. The study shows the presence of different reaction layers in the diffusion zone and their chemical compositions were determined by energy dispersive spectroscopy. The occurrence of different intermetallic phases such as FeTi, λ, χ, and σ has been predicted from the ternary phase diagram of Fe - Cr - Ti and they were confirmed by the X-ray diffraction technique. A maximum bond strength 76% of that of titanium was obtained for the diffusion couple processed at 800 ° C owing to finer size intermetallic compounds and the increment in joining temperature, which results in growth of brittle intermetallics leading to a sharp fall in the strength of the transition joints. 相似文献
20.
Diffusion Bonding of Silicon Carbides Silicon carbide is a material that is suitable for high temperature application, especially for heat exchangers at high temperatures. Besides the problem of producing large components out of ceramics a technique for joining silicon carbide has to be developed. At high temperatures the joint has to be gastight und sufficient strength must be guaranteed. Diffusion bonding proved to be a good technique. The temperatures necessary for diffusion bonding are around 1200 °C, inert atmosphere or vacuum was used. The parameters of the procedures are discussed and correlated to strength, microstructure and permeability for gases. 相似文献