Papers by Keyword: Transient Liquid Phase (TLP) Bonding

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Authors: Shinji Koyama, Makoto Takahashi, Kenji Ikeuchi
Abstract: The bond interface of a TLP (Transient Liquid Phase) bonded tin has been observed with a TEM to investigate the effect of the liquid phase on the behavior of the superficial oxide film at the interface during the bonding process. In the solid-state-diffusion bonded joint without filler, abundant oxide inclusions were observed to be distributed within a region of a few 100 nm widths along the bond interface. In comparison with this, the liquid phase introduced by the eutectic reaction of the bismuth filler with the tin substrate decreased the width of the interfacial region involving abundant oxide inclusions to form a rather layer structure a few 100 nm thick consisting mainly of SnO2. It also enhanced the annihilation of the uncontacted areas at the interface. The layer of the oxide became discontinuous and coalesced with an increase in bonding temperature and pressure, and areas where no oxide inclusion could be observed at the interface were increased, when the liquid phase was formed. Owing to these effects, the bond strength rose at lower bonding temperatures and pressures when the bismuth filler was applied.
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Authors: Hong Wang, Qian Yan, Xin Geng Li, Xue Gang Wang, Xiao Ming Wang, Feng Jie Yan
Abstract: The key to accomplish transient liquid phase bonding in the atmosphere is to control bonding temperature, holding time and compressive pressure. The measurement and control system was independently developed based on an industrial computer and I/O cards. The output of a medium frequency power supply and the opening degree of a proportional relief valve were regulated to control bonding temperature and compressive pressure. Improved PID algorithm was presented, and the temperature precision in steady stage reached ± 0.1%. The system is applied to TLP bond steel pipes successfully.
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Authors: Si Jie Chen, Si Jing Guo, Feng Liang
Abstract: T91/12Cr2MoWVTiB was bonded by transient liquid phase bonding process with different pressures, one commercial FeNiCrSiB was used as the interlayer. The microstructure and components distribution of the bonded joints were examined by optical microscope and scanning electron microscopic techniques. Furthermore, the properties of the joints were also tested. The results indicate that with the increase of the pressure – from 2 MPa to 6 MPa – the microstructures and mechanical properties were improved, and more similar to those base alloys. A theoretical study also revealed that the isothermal solidification complication time can be shorter, because the maximum liquid width was reduced with the existence of pressure.
107
Authors: T. Li, Qing Yuan Wang, Ai Qin Wang, Z.X. Wen, Zhu Feng Yue
Abstract: In this paper, the mechanical behavior of Ni-base single crystals joint created by TLP bonding is presented. Experimental study has been performed on the TLP single crystal under loading conditions of static uniaxial tension, creep and Three-points-bending (T-P-B) at temperature of 850 °C. Specimens made of the base material, Ni-base single crystal specimens without bonding, were also tested under the same loading conditions. The mechanical behaviors of TLP single crystal is compared to the behaviors of base material. It was found that the static strength of the TLP specimens with the boundary normal to the tensile direction was 63% of the strength of the base material. The creep strength and the fracture ductile strength was more than 57% and 55% of that of the single crystal base material, respectively. The macro and micro graphs of fracture surfaces of specimens indicated that the fracture modes of the samples were brittle fracture.
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Authors: Flora Somidin, Stuart D. McDonald, Kazuhiro Nogita
Abstract: This paper presents the use of the transient liquid phase concept to grow the high temperature Cu6Sn5 intermetallic compound between Cu3Sn-rich powdered alloys and molten Sn. In this study, high temperature powdered alloys containing high fractions of Cu3Sn were fabricated from a chill-cast Sn-60 wt.%Cu alloy. A ternary alloy with composition of Sn-59 wt.%Cu-1 wt.%Ni was also prepared to investigate the effect of Ni. The reaction products were obtained at 250°C over a period of 30 minutes. The results provide new insight into the mechanism of the interfacial reaction between liquid Sn and solid Cu3Sn-rich alloy with and without Ni additions.
14
Authors: Shinji Fukumoto, Akio Hirose, Kojiro F. Kobayashi
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Authors: Muhammad A. Arafin, Mamoun Medraj, Daniel P. Turner, Philippe Bocher
Abstract: Mathematical model, based on Fick’s second law of diffusion, was used to predict the time required to complete isothermal solidification and to determine the effect of process variables during the transient liquid phase bonding of Inconel 625 and 718 superalloys with nickel based brazing filler alloy BNi-2. Experimental investigations were carried out in the range of 1325 – 1394K to verify the model and the predicted times were in excellent agreement with the experimentally determined values. The obtained activation energies for diffusion of boron were very close to the ones reported for other nickel base polycrystalline superalloys; however, it was observed that the time required for complete isothermal solidification are significantly less than that of other nickel based superalloys with different nickel based brazing filler alloys. Because of this advantage, these combinations of base and filler alloys are expected to replace other currently used ones. Further, significant reduction of holding time was observed with increasing brazing temperature and with decreasing joint gap. The composition of the joints at the end of holding period, when the holding time was not sufficient to complete isothermal soldification, has been determined in order to predict the amount of brittle eutectic phases in the final joint microstructures.
882
Authors: Yao Chu, Shi Hang Jiang, Wei Jian Fan, Zhao Yang Jin, Du Xiong Wang
Abstract: Transient liquid-phase(TLP) bonding of SiC particle reinforced aluminum matrix composite(SiCp/Al MMCs) ,using Cu film, Cu foil, Ni foil and Cu/Ni/Cu multilayer foil interlayer, was investigated. The effect of surface status, interlayer species and bolding time on bonding microstructure and properties were also estimated by metallographic microscope, scanning electron microscopy (SEM), X ray diffraction and tensile testing machine. The results show that adding holding time can improve shear strength of joint. Better strength of joint can be obtained due to without the effect of oxide with Cu film as interlayer, when bonding at 853K for 120min under 2MPa pressure, the shear strength of bonded joints can obtain 169.1MPa, about 81.7 percentage of the strength of base material. Best strength of joint can be obtained with Cu/Ni/Cu multilayer foil as interlayer, when bonding at 923K for 120min under 2MPa pressure, the of bonded joints can obtain 189.6MPa, about 84.6 percentage of the strength of base material.
44
Authors: Rong Fa Chen, Yi Hong Zhao, Zhao Xia Shen, Liang Gang Dai, Xian Liang Zhang, Rui Zhu
Abstract: Transient liquid-phase (TLP) bonding of aluminium-based metal matrix composite (MMC) has been investigated. An attempt was made of using an Ag/Cu /Ag film as an interlayer for bonding to improve the joint strength. The oxide on the surface of SiCp/Al MMC was etched completely by plasma. Ag/Cu/Ag film of 8µm thickness was prepared by magnetron sputtering method on the clean bonding surface in the same vacuum chamber. Compared with the same thickness of single Cu foil and Ni foil interlayer, which are widely used for joining SiCp/Al MMC material, the shear strength of 192.8MPa was obtained, which was 86.5% that of base metal. Discussion was made on the bonding process and microstructure.
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