• Transactions of Materials Processing
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• v.8 no.3
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• pp.227-227
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• 1999

The effects of intermediate annealing (IA) and the final cold rolling (CR) condition on the microstructure and sagging resistance during brazing were investigated using three layer clad sheets composed of the Al-7.5 wt.%Si alloy (filler, thickness: 10 ㎛)/Al-1.3 wt.%Mn based alloy (core, 80㎛)/Al-7.5 wt.%Si alloy (filler, 10㎛). Also, the effect of 1.2∼2 wt.% Zn addition into the core on the sagging resistance of the clad sheets was determined. It was revealed that all the clad sheets fabricated by the optimum condition (IA at 690 K and CR to 20∼45%) show excellent sagging resistance with a limited erosion due to the formation of a coarsely recrystallized grain structure in the core during brazing. It was also revealed that the recrystallization behavior of the Al-1.3 wt.%Mn based alloy is hardly affected by the addition of 1.2-2 wt.%Zn during the brazing cycle. Therefore, the sagging resistance of the clad sheets is found to be governed not by the Zn content added in the A1-1.3wt.%Mn based core, but by the intermediate annealing and final cold rolling condition.

• 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 Welding and Joining
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• v.28 no.3
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• pp.49-58
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• 2010

Various alloy system, such as Cu-Sn-Ti, Cu-Ag-Ti, and Ni-B-Cr-based alloy are used for the brazing of diamond grits. However, the problem of the adhesion strength between the diamond grits and the brazed alloy is presented. The adhesion strength between the diamond grits and the melting filler alloy is predicted by the contact angle, thereby, instead of diamond grit, the study on the wettability between the graphite and the brazing alloy has been indirectly executed. In this study, Cu-13Sn-12Ti filler alloy was manufactured, and the contact angles, the shear strengths and the interfacial area between the graphites (diamond grits) and braze matrix were investigated. The contact angle was decreased on increasing holding time and temperature. The results of shear strength of the graphite joints brazed filler alloys were observed that the joints applied Cu-13Sn-12Ti alloy at brazing temperature $940^{\circ}C$ was very sound condition indicating the shear tensile value of 23.8 MPa because of existing the widest carbide(TiC) reaction layers. The micrograph of wettability of the diamond grit brazed filler alloys were observed that the brazement applied Cu-13Sn-12Ti alloy at brazing temperature $990^{\circ}C$ was very sound condition because of existing a few TiC grains in the vicinity of the TiC layers.

• Korean Journal of Metals and Materials
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• v.48 no.4
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• pp.289-296
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• 2010

The effects of heat input and different microstructureswere investigated on the tensile-shear properties of an arc-brazed joint of theferritic stainless steel 429EM using a Cu-Si insert alloy. The brazing speed was fixed at 800 mm/min whilethe brazing current varied from 80 to 120A. For abrazing current lower than 100A, fracturing occurred at the joint root in the direction perpendicular to the tensile load. As the brazing current increased to 120A, fracturing occurred at the base metal or the joint root. The joint and the base metal had very similar yield and tensile load values. However, the amount of elongation was decreased considerably compared to when the base metal was used. The fracturing began at the triple point of the root part and was classified into three types. The difference in the tensile-shear properties was closely related to the three fracture types.

• Journal of Welding and Joining
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• v.15 no.2
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• pp.43-53
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• 1997

The complete joining method for dissimilar press punch materials and its real-time evaluation method is not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction welding with a diffusion mechanism in bonding was applied in this study. This work was carried out to determine the proper friction welding conditions and to analyze mechanical properties of friction welded joints of sintered carbide tool materials (SKNM50 for the blade part of press punch) to alloy steel (SCM440 for the shank part of press punch) using aluminum (A6061 for the interlayer material) as an insert material between the sintered carbide tool materials and the alloy steel. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.382-392
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• 1990

This study investigates the behavior of fatigue crack propagating between holes of holes filled with another materials. When holes of the holes filled with another materials are located symmetrically near a center crack, it is noted that the crack propagation rate is influenced by both the bonding force of the brazing part and the elastic modulus of another material. It is experimentally and analytically confirmed that the center crack stops when its tip reaches near the center line of the holes and a small crack is initiated from the boundaries of holes of the holes filled with another materials and it propagates to final fracture.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05a
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• pp.78-79
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• 1992

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05a
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• pp.82-83
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• 1992

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.49-49
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• 1993

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.05a
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• pp.10.2-10.2
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• 2006