scholarly journals A metallographic investigation of the effect of bonding pressure and surface finish on isostatic diffusion bonding of Ti-25Al-10Nb-3Mo-1V

2016 ◽  
Vol 53 (02) ◽  
pp. 97-103
Author(s):  
S. TALAS ◽  
T. I. KHAN
2017 ◽  
Vol 115 (1) ◽  
pp. 115 ◽  
Author(s):  
Gopinath Thirunavukarasu ◽  
Sukumar Kundu ◽  
Tapas Laha ◽  
Deb Roy ◽  
Subrata Chatterjee

An investigation was carried out to know the extent of influence of bonding-time on the interface structure and mechanical properties of diffusion bonding (DB) of TiA|Cu|SS. DB of Ti6Al4V (TiA) and 304 stainless steel (SS) using pure copper (Cu) of 200-μm thickness were processed in vacuum using 4-MPa bonding-pressure at 1123 K from 15 to 120 min in steps of 15 min. Preparation of DB was not possible when bonding-time was less than 60 min as the bonding at Cu|SS interface was unsuccessful in spite of effective bonding at TiA|Cu interface; however, successful DB were produced when the bonding-time was 60 min and beyond. DB processed for 60 and 75 min (classified as shorter bonding-time interval) showed distinctive characteristics (structural, mechanical, and fractural) as compared to the DB processed for 90, 105, and 120 min (classified as longer bonding-time interval). DB processed for 60 and 75 min exhibited layer-wise Cu–Ti-based intermetallics at TiA|Cu interface, whereas Cu|SS interface was completely free from reaction products. The layer-wise structure of Cu–Ti-based intermetallics were not observed at TiA|Cu interface in the DB processed for longer bonding-time; however, the Cu|SS interface had layer-wise ternary intermetallic compounds (T1, T2, and T3) of Cu–Fe–Ti-based along with σ phase depending upon the bonding-time chosen. Diffusivity of Ti-atoms in Cu-layer (DTi in Cu-layer) was much greater than the diffusivity of Fe-atoms in Cu-layer (DFe in Cu-layer). Ti-atoms reached Cu|SS interface but Fe-atoms were unable to reach TiA|Cu interface. It was observed that DB fractured at Cu|SS interface when processed for shorter bonding-time interval, whereas the DB processed for longer bonding-time interval fractured apparently at the middle of Cu-foil region predominantly due to the existence of brittle Cu–Fe–Ti-based intermetallics.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1266 ◽  
Author(s):  
Han Mei ◽  
Lihui Lang ◽  
Xiaoxing Li ◽  
Hasnain Ali Mirza ◽  
Xiaoguang Yang

Due to the acceptable high-temperature deformation resistance of Inconel 718, its welding parameters such as bonding temperature and pressure are inevitably higher than those of general metals. As a result of the existing punitive processing environment, it is essential to control the deformation of parts while ensuring the bonding performance. In this research, diffusion bonding experiments based on the Taguchi method (TM) are conducted, and the uniaxial tensile strength and deformation ratio of the experimental joints are measured. According to experimental data, a deep neural network (DNN) was trained to characterize the nonlinear relationship between the diffusion bonding process parameters and the diffusion bonding strength and deformation ratio, where the overall correlation coefficient came out to be 0.99913. The double-factors analysis of bonding temperature–bonding pressure based on the prediction results of the DNN shows that the temperature increment of the diffusion bonding of Inconel 718 significantly increases the deformation ratio of the diffusion bonding joints. Therefore, during the multi-objective optimization of the bonding performance and deformation of components, priority should be given to optimizing the bonding pressure and duration only.


Author(s):  
S. K. Tiwari ◽  
B. K. Paul

Transient liquid phase diffusion brazing is used in precision, hermetic joining applications as a replacement for diffusion bonding to reduce cycle times, reduce bonding pressure, and improve yields. In the present study, stainless steel 316L laminae are diffusion brazed with an interlayer of nickel nanoparticles and compared with samples joined by conventional diffusion bonding and electroplated nickel-phosphorous diffusion brazing. Comparison is made with regard to microstructural evolution, diffusional profile, and bond strength. All bonding was carried out in a uni-axial vacuum hot press at 1000°C with a heating rate of 10°C/min, a dwell time of 2 h and a bonding pressure of 10 MPa. Bond strength measurements show that the sample brazed with a nickel nanoparticle interlayer has the lowest void fraction at 4.8±0.9% and highest shear strength at 141.3±7.0 MPa. Wavelength dispersive spectroscopic analysis of sample cross-sections shows substantial diffusion of Ni and Fe across the nickel nanoparticle bond line. Scanning electron micrographs show no secondary phases along the nickel nanoparticle bond line.


2019 ◽  
Vol 15 (6) ◽  
pp. 1037-1052
Author(s):  
A. Arun Negemiya ◽  
S. Rajakumar ◽  
V. Balasubramanian

Purpose The purpose of this paper is to develop an empirical relationship for predicting the strength of titanium to austenitic stainless steel fabricated by diffusion bonding (DB) process. Process parameters such as bonding pressure, bonding temperature and holding time play the main role in deciding the joint strength. Design/methodology/approach In this study, three-factors, five-level central composite rotatable design was used to conduct the minimum number of experiments involving all the combinations of parameters. Findings An empirical relationship was developed to predict the lap shear strength (LSS) of the joints incorporating DB process parameters. The developed empirical relationship was optimized using particle swarm optimization (PSO). The optimized value discovered through PSO was compared with the response surface methodology (RSM). The joints produced using bonding pressure of 14 MPa, bonding temperature of 900°C and holding time of 70 min exhibited a maximum LSS of 150.51 MPa in comparison with other joints. This was confirmed by constructing response graphs and contour plots. Originality/value Optimizing the DB parameters using RSM and PSO, PSO gives an accurate result when compared with RSM. Also, a sensitivity analysis is carried out to identify the most influencing parameter for the DB process.


2015 ◽  
Vol 787 ◽  
pp. 495-499 ◽  
Author(s):  
K. Dheenadayalan ◽  
S. Rajakumar ◽  
V. Balasubramanian

In this investigation, Commercially Pure (Cp) titanium was diffusion bonded to AA7075-T6 aluminium alloy at various temperatures of 450, 475, 500, 525 and 5500C, bonding pressure of 17, MPa and holding time of 40 minutes was applied during the diffusion bonding. The effects of reaction temperature, Bonding time and atmosphere on the diffusion welding characteristics of titanium and aluminum have been studied. The maximum Lap shear strength was found to be 89 MPa for the specimen bonded at the temperature of 525°C, Bonding Pressure 17 MPa and Holding time for 40 min.


2008 ◽  
Vol 580-582 ◽  
pp. 295-298
Author(s):  
Gui Sheng Zou ◽  
Yan Ju Wang ◽  
Ai Ping Wu ◽  
Hai Lin Bai ◽  
Nai Jun Hu ◽  
...  

To improve the joining efficiency of Bi-Sr-Ca-Cu-O ( BSCCO) superconducting tapes, a new diffusion bonding technology with a direct uniaxial pressing at high temperature was developed to join 61-filament tapes. It was observed that bonding parameters such as bonding pressure and holding time, significantly affected the critical current ratio (CCRo). A peak CCRo value of 89 % for the lap-joined tapes was achieved at 3 MPa for 2 h when bonding temperature was 800 °C. Compared with the conventional diffusion bonding technology, this new technology remarkably shortened the fabrication period and improved the superconductivity of the joints. The bonding interface and microstructures of the joints were evaluated and correlated to the CCRo. An uniaxial pressing at high temperature was beneficial to interface bonding, and there was an optimal pressure value for the CCRo.


Author(s):  
Nader Nadermanesh ◽  
Abdolhamid Azizi ◽  
Sahebali Manafi

The diffusion bonding of 7075, 6061 and 5083 aluminium alloys to AZ31B magnesium was investigated using copper interlayer. An optical microscope along with scanning electron microscopes, equipped with an energy dispersive spectrometry/electron probe microanalysis, was utilized to characterize the microstructure of the joint. The mechanical properties of the joint were also assessed by micro-hardness and shear strength tests. The results indicate the high effect of temperature on the bonding results; so that, with a small change in temperature, severe changes were observed in the bonding results. A temperature range of 475°C–485°C and a minimum duration of 30 min with a low bonding pressure of 0.4 MPa were identified as advisable process conditions. The joint evaluation revealed the formation of CuAl2, Cu9Al4 and Al-Mg-Cu ternary phases on the aluminium-copper side, as well as Cu2Mg, CuMg2 and Al-Mg-Cu ternary phases on the magnesium-copper side in the reaction layer. When increasing the bonding temperature and duration, the amount of intermetallic compounds and, as a result, the mechanical properties of the joints changed. The highest shear strength and micro-hardness, related to the bonding performed at 480°C and holding time of 45 min, were 31.03 MPa and 167 HV, respectively.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
A. Arun Negemiya ◽  
A. N. Shankar ◽  
B. Guruprasad ◽  
B. Prakash ◽  
S. Dineshkumar ◽  
...  

The diffusion bonding (DB) method is used in this investigation to connect high-temperature dissimilar materials. The existence of difficult-to-remove oxide coatings on the titanium surfaces, as well as the arrangement of breakable metallic interlayers and oxide enclosures inside the bond region, provides the most significant challenges during the transition from AISI304 to Ti-6Al-4V alloying. In addition, an effort was made to advance DB processing maps for the operational connection of Ti-6Al-4V to AISI304 alloys to improve their performance. Joints had been created by combining several process factors, such as bonding temperature (T), bonding pressure (P), and holding time (t), to create diverse designs. Based on the findings, database processing maps were created. This set of processing maps may be used as a rough guideline for selecting appropriate DB process parameters for generating virtuous excellent bonds between Ti-6Al-4V and AISI304 alloys. The maximum lap shear strength (LSS) was achieved at 800°C, 15 MPa, and 45 min.


Author(s):  
Anas M. Atieh ◽  
Tahir I. Khan

Magnesium is the lightest structural metal and recently magnesium and its alloys have received increased attention in various engineering applications. Titanium is a light metal and shows excellent corrosion resistance and high specific strength. The ability to join these two metals together can increase their use in the automotive and aerospace industries. However, differences in the physical properties of these alloys (e.g. melting point for Ti-6Al-4V is 1650°C and 680°C for AZ31) make the joining of these dissimilar alloys a great challenge. This research work presents the effect of one of the most important parameters in diffusion bonding; the bonding pressure. Optimizing bonding parameters resulted in sound joint with homogeneous microstructure and suitable mechanical properties. To join these two alloys the diffusion bonding was carried out using thin (20μm) pure Ni foils at different bonding pressures (0.2 and 0.7 MPa) at 515°C as a function of holding time of 5 to 30 minutes. The results showed a direct relation exist between bonding pressure, joint microstructure and mechanical properties. Reaction zones were identified inside bonding region and tested with respect to hardness profile. In case of 0.2 MPa pressure the joint width increased from 86μm for bonding time of 5 minutes to 197μm for 20 minutes. A decrease in joint width to 144μm at bonding time of 30 minutes shows that isothermal solidification starts for a bonding time of 20 minutes. However, when bonding at 0.7 MPa pressure the joint width increased from 59 μm for bonding time of 5 minutes to 156 μm at 10 minutes. A decrease to 123 μm at bonding time of 20 minutes was recorded. Even further decrease to 75 μm at bonding time of 30 minutes was noticed. This suggest Isothermal solidification takes place in case of 0.7 MPa earlier than in case of 0.2 MPa.


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