• Journal of Welding and Joining
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• v.30 no.6
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• pp.21-26
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• 2012

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.207-210
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• 2000

• Proceedings of the KWS Conference
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• 2000.10a
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• pp.222-223
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• 2000

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.61-68
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• 2023

In this study, Sn-3.5Ag-15.0Fe composite solder was manufactured and applied to TLP bonding to change the entire joint into a Sn-Fe IMC(intermetallic compound), thereby applying it as a high-temperature solder. The FeSn₂ IMC formed during the bonding process has a high melting point of 513℃, so it can be stably applied to power modules for power semiconductors where the temperature rises up to 280℃ during use. As a result of applying ENIG surface treatment to both the chip and substrate, a multi-layer IMC structure of Ni₃Sn₄/FeSn₂/Ni₃Sn₄ was formed at the joint. During the shear test, the fracture path showed that cracks developed at the Ni₃Sn₄/FeSn₂ interface and then propagated into FeSn₂. After 2hours of the TLP joining process, a shear strength of over 30 MPa was obtained, and in particular, there was no decrease in strength at all even in a shear test at 200℃. The results of this study can be expected to lead to materials and processes that can be applied to power modules for electric vehicles, which are being actively researched recently.

• Journal of Welding and Joining
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• v.21 no.4
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• pp.69-74
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• 2003

The mechanical properties of STD11 Joints by using TLP (Transient Liquid Phase Diffusion) bonding method employing MBF-30 and MBF-80 insert metals were investigated with concerning to the microstructural change. TLP bonding of STD 11 was carried out at 1323∼1423K for 0.6ks∼3.6ks in vacuum. The microstructure and the element distribution of the interlayer between tool steels and insert metals showed specific feature with bonding conditions. It was found that the width of the interlayer increased at initial bonding stage. However, the width of interlayer showed nearly constant value during the isothermal solidification. After isothermal solidification was completed, the joint showed homogeneous element distribution and similar microstructure with base metal because of the grain boundary migration to the bonded interlayer. The bonding strength measured by a tensile test has been varied with the bonding conditions. The maximum joint strength, 760MPa, was obtained with the condition of 1423K for 1.2ks using MBF30 insert metal in this experiment.

• Journal of Welding and Joining
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• v.9 no.3
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• pp.26-33
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• 1991

As it takes very long time for the Transient Liquid Phase(TLP) bonding, we tried to reduce the bonding time by changing insert material for the high diffusivity element. On this study boron powder was doped as a insert material on the bonding surface of Rene 80 superalloy, and diffusion treated at 1150.deg.C under vacuum. On this method differently from the TLP bonding the insert material was not melted during bonding but only the base metal reacted with the boron was inducedly melted. Therefore, as this bonding mechanism is different from the existing ones, it is suggested as a Melting Induced Diffusion Bonding. When this process was used for the diffusion bonding, the bonding time including homogenization decreased greatly compared to the conventional TLP bonding.

• Journal of Welding and Joining
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• v.35 no.3
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• pp.52-61
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• 2017

Transient liquid phase (TLP) bonding is essential technology to repair micro-cracking on the airfoil of blades and vanes for gas turbines. Understanding of the characteristics of TLP bonding of the superalloys is necessary in the application of the technology for repairing these components. In this study, the focus was on investigating TLP bonding characteristics of ${\gamma}^{\prime}$ precipitation strengthened Ni based superalloy. TLP bonding was carried out with an amorphous filler metal in various bonding conditions, and the microstructural characterization was investigated through optical microscopy (OM) and electron probe micro-analysis (EPMA). The experimantal results explained clearly that bonding temperatures had critical effects on the TLP bonding behaviors, and that isothermal solidication of the joints made at higher temperatures than $1170^{\circ}C$ was controlled by Ti diffusion instead of B.

• Journal of Welding and Joining
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• v.20 no.5
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• pp.93-98
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• 2002

The effect of bonding misfit on single crystallization of transient liquid phase (TLP) bonded joints of single crystal superalloy CMSX-2 was investigated using MBF-80 insert metal. The bonding misfit was defined by (100) twist angle (rotating angle) at bonded interface. TLP bonding of specimens was carried out at 1523K for 1.8ks in vacuum. The post-bond heat treatment consisted of the solution and sequential two step aging treatment was conducted in the Ar atmosphere. The crystallographic orientation analysis across the TLP bonded joints was conducted three dimensionally using the electron back scattering pattern (EBSP) method. EBSP analyses f3r the bonded and post bonded heat treated specimens were conducted. All bonded joints had misorientation centering around the bonded interface for as-bonded and post-bond heat treated specimens with rotating angle. The average misorientation angle between both solid phases in bonded interlayer was almost identical to the rotating angle at bonded interface. HRTEM observation revealed that the atom arrangement of both solid phases in bonded interlayer was quite different across the bonded interface. It followed that grain boundary was formed in bonded interface. It was confirmed that epitaxial growth of the solid phase occurred from the base metal substrates during TLP bonding and single crystallization could not be achieved in joints with rotating angle.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.55-62
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• 2023

In this study, Sn-3.0Ag-0.5Cu (wt.%, SAC305) solder dipping process was performed between Ni-foam skeleton with different pore per inch (PPI) to fabricate Ni-foam/SAC305 composite solder, and then applied to the transient liquid phase (TLP) bonding process to evaluate the microstructure and mechanical properties of the bonded joint. The Ni-foam/SAC305 composite solder preform consisted of Ni-foam and SAC305, and an intermetallic compound (IMC) having a (Ni,Cu)₃Sn₄ composition was formed at the Ni-foam interface. During TLP bonding process, the IMC at the Ni-foam interface was converted to (Ni,Cu)₃Sn₄+Au, and as the bonding time increased, the Ni-foam and SAC305 continuously reacted, and the bonded joint was converted into an IMC. And it was confirmed that the 130 PPI Ni-foam/SAC305 composite solder joint was converted into an IMC at the fastest rate. As a result of performing a shear test to confirm the effect of Ni-foam on mechanical properties, solder joints under all conditions exhibited excellent mechanical properties of 50 MPa or more in the early stages of the TLP bonding process, and the shear strength tends to increase as the bonding time increases.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.113-119
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• 2013

The transient liquid phase (TLP) bonding was used to fabricate autogenous joints in a magnesium alloy AZ31 with the aid of a pure Ni interlayer. A $13{\mu}m$ thick pure Ni foil was used in order to form a Mg-Ni eutectic liquid at the joint interface. The interface of reaction and composition profiles were investigated as a function of bonding time using a pressure of 0.16 MPa and a bonding temperature of $515^{\circ}C$. The quality of the joints produced was examined by metallurgical characterization and the joint microstructure developed across the diffusion bonds was related to changes in mechanical properties as a function of the bonding time.