• Journal of Korea Foundry Society
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• v.30 no.5
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• pp.187-195
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• 2010

In this study, in order to obtain a useful guide line for design and production of automotive heat exchanger components made of 4343/3003/4343 aluminum clad sheets, it was aimed to improve the understanding about the grain refinement effect on brazing characteristic of the clad sheets. Al-10Ti master alloy was used for grain refinement of 3003 core alloy, and the Ti inoculation level was systematically changed up to 0.1 wt%. The three-layer aluminum clad sheets were fabricated by hot roll bonding process. The effect of grain refinement on brazing characteristic of the clad sheets was investigated by evaluating wettability, bonding strength and sagging resistance.

• Journal of Welding and Joining
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• v.24 no.5
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• pp.1-6
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• 2006

• Journal of the Korean Ceramic Society
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• v.39 no.10
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• pp.955-962
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• 2002

The microstructure change of brazed $Si_3N_4$/Stainless steel 316 joint with Cu buffer layer were examined to clarify the effects of brazing process conditions such as brazing time and temperature on the mechanical properties and reliability of brazed joints. For the brazed joint above 900${\circ}C$, the Cu buffer layer was completely dissolved into brazing alloy and the thickness of reaction product formed at $Si_3N_4$/brazing alloy joint interface was abruptly increased, which could increase the amounts of residual stress developed in the joint. The fracture strength of brazed $Si_3N_4$/Stainless steel 316 joint with Cu buffer layer at 950${\circ}C$ was much reduced comparing to those of joints brazed at the lower temperature. But, it was found that the effects of brazing time was not critical on the mechanical properties as well as the reliability of $Si_3N_4$/Stainless steel 316 joint with Cu buffer layer brazed at the temperature below 900${\circ}C$.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.1
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• pp.66-72
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• 1993

The brazing of Al to Al using Al-Si alloy filler metal was performed under different bonding conditions such as ratio of lap length to plate thickness, surface roughness and joint clearance of the lap joint. The adopted thickness of the base metal in this experiments were two kinds of 4mm and 7mm which were most commonly used in various field. Influence of several bonding conditions of Al/Al joint was quantitavely evaluated by bonding strength test, and microstructural analysis at the interlayer were performed by optical microscope. From above experiments, the optimum bonding conditions of the brazing bonding of Al/Al using Al-Si alloy filler metal was determined. The major results obtained are as follows. 1) The fracture occurs at brazed joint in the conditions of that the ratio of lap length to plate thickness is less than 2 in case of 7mm plate thickness. 2) The ratio of lap length to plate thickness which the fracture occurs at base metal is decreased with the decreasing of the plate thickness. 3) The joint strength is not affected by the surface roughness and joint clearance of the brazed part. 4) The heat-treatment of the brazed joint contribute to eliminate the boundary between the base metal and filler metal. However, the joint strength is not affected by the heat-treatment.

• 연구논문집
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• s.27
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• pp.201-208
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• 1997

To improve the joining characteristics of metallic converter substrate for exhaust gas cleaning, high temperature brazing process has been studied. In this study, the effect of chemical composition of brazing filler metal on the oxidation behavior of brazed joints was investigated closely. Brazing was carried out at $1200^\circC$ in vacuum furnace using nickel-based filler metals : BNi-5 powder(Ni-Cr-Si base alloy) and MBF-50 foil(Ni-Cr-Si-B). The MBF-50 containing 1-1.5 wt%B showed relatively poor oxidation resistance of the brazed joints compared to BNi-5, because of the faster invasion of oxygen through the Kirkendal voids along the interface of mother alloy/filler metal.

• Korean Journal of Materials Research
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• v.26 no.7
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• pp.376-381
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• 2016

For the development of a low-melting point filler metal for brazing aluminum alloy, we analyzed change of melting point and wettability with addition of Sn into Al-20Cu-10Si filler metal. DSC results showed that the addition of 5 wt% Sn into the Al-20Cu-10Si filler metal caused its liquidus temperature to decrease by about 30 oC. In the wettability test, spread area of melted Al-Cu-Si-Sn alloy is increased through the addition of Sn from 1 to 5 wt%. For the measuring of the mechanical properties of the joint region, Al 3003 plate is brazed by Al-20Cu-10Si-5Sn filler metal and the mechanical property is measured by tensile test. The results showed that the tensile strength of the joint region is higher than the tensile strength of Al 3003. Thus, failure occurred in the Al 3003 plate.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.555-560
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• 2002

Brazing of Al to Cu using AI-Si-Mg-Bi brazing alloy has been carried out in the vacuum furnace. In the bonded interlayer, there were two kinds of intermetallic compounds. One of these intermetallic compounds was e phase and the other was b phase. The growth of b phase was controlled by diffusion Al into Cu. Deformation behavior of Al-Cu brazing joint was brittle without deformation of the base metal. Shear strength of the joint was only about 20MPa. The shear specimen broken in the intermetallic compound, which was mainly e phase. Shear strength did not depend on the bonding temperature.

• Journal of the Korean Society for Heat Treatment
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• v.21 no.6
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• pp.300-306
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• 2008

Solid state diffusion brazing of aluminum castings (AC4C) and wrought alloys (Al6061) was conducted in order to improve thermal conductivity and temperature uniformity of the aluminum heater which was generally fabricated by casting method. Tensile strength and thermal conductivity are raised with increasing brazing temperature, obtaining 122.5 MPa and $206W/m{\cdot}K$ at $540^{\circ}C$ 5hrs brazing conditions, respectively. The diffusion brazed heater, shows maximum temperature difference of $4^{\circ}C$, exhibits a enhanced temperature uniformity compared with the cast heater having the maximum temperature difference of $11^{\circ}C$.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.48-50
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• 2005

Advanced hard materials based on diamond are in common use. In this study our main goal was employed to analyze, the mechanisms for the rich phases and chromium carbide, interface of a diamond grits brazed to a Ni-based brazing filler metal matrix. When Ni-7Cr-3Fe-3B-4Si (wt. %) was utilized as the brazing alloy, an isothermal holding resulted in the various products(Ni-rich/Cr-rich domains, carbide). According to these results, the chemical compounds and chromium carbides products is considered to play an important role in brazing temperature and time. Especially chromium carbide has an influence on brazing junction properties.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1307-1308
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• 2006

The purpose of this study was to examine the interfacial reaction between diamond grits and Ni-based, Ag-based, brazing filler metal, respectively. The morphology of the interface between diamond grits and Ni-based, filler metal exhibited a very good condition after this heat treatment. Cr-carbide and Ni-rich compounds were detected by XRD analysis in the vicinity of the interface between diamond grits and Ni-based, filler metal after vacuum induction brazing. Chromium carbide is considered to play an important role in the high bonding strength achieved between diamonds grits and the brazing alloy.