• Transactions of Materials Processing
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• v.29 no.1
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• pp.49-54
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• 2020

The influence of electric current on the joining properties of aluminum and copper was investigated. Various pulsed electric current conditions were set to the joining specimens followed by pressure. The shear strength of the joint area between aluminum and copper was measured by the lab shear test. In addition, the microstructures of the joint area were observed through a field emission scanning electron microscope, energy dispersive X-ray, and electron backscatter diffraction. The mechanical properties of each phase in the joint region were measured by nano-indentation. As a result, it was confirmed that electrically assisted solid state joining of copper and aluminum could be applied in various industrial fields.

• Journal of Welding and Joining
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• v.15 no.6
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• pp.32-40
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• 1997

Solid state diffusion bonding is the joining process performed by creep and diffusion, which is accelerated by heating below melting temperature and proper pressing, in vacuum or shielding gas atmosphere. By this process we can obtain sufficient joint which can't be expected from the fusion welding. For Ti-6Al-4V alloy, the optimum solid state diffusion bonding condition and mechanical properties of the joint were found, and micro void morphology at bond interface was observed by SEM. The results of tensile test showed sufficient joint, whose mechanical properties are similar to that of base metal. 850$^{\circ}$C, 3MPa is considered as the optimum bonding condition. Void morphology at interface is long and flat at the initial stage. As the percentage of bonded area increases, however, small and round voids are found. Variation of void shape can be explained as follows. As for the void shrinkage mechanism, at the initial stage, power law creep is the dominant, but diffusion mechanism is dominant when the percentage of bonded area is increased.

• Transactions of Materials Processing
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• v.31 no.6
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• pp.337-343
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• 2022

Electrically assisted pressure joining (EAPJ) utilizes electric current-induced kinetic enhancement to achieve solid state diffusion bonding within a short time. In this study, aluminum alloy specimens, which are known as a hard-to-weld metal, were successfully solid-state joined through EAPJ. The bonding process was performed in two ways: continuous direct current (CDC), which applies relatively low current density, and pulsed direct current (PDC), which applies high current density. It was observed that the bonding strength was higher in PDC than in CDC. The microstructure of the joint was characterized using 3D X-ray microscopy (XRM) and electron backscatter diffraction (EBSD).

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.282-288
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• 2002

A new on-line bar joining technology employing the concept of a solid-state joining has been developed for the endless rolling by POSCO, RIST and MHMM Inc.. In the process, the bars are partially descaled, partially overlapped, joined by shearing action and crops are finally removed. The feasibility of the developed process was evaluated in this study in terms of microstructures and mechanical properties of joints, and the response of the joint to rolling.

• Journal of Welding and Joining
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• v.10 no.3
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• pp.63-72
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• 1992

The joining methods of ceramics to metals which can be expected to obtain high temperature strength are mainly classified into the solid-state diffusion bonding method and the active brazing method. Between these two, the solid-state diffusion bonding method is given attentions as substituting method for active brazing method due to being capable of obtaining higher bonding strength at high temperature and accurate bonding. In this paper, the solid-state diffusion bonding of $Al_{2}$O$_{3}$ ceramics to Ni-Cr-Mo alloy steel (SNCM21) using insert metal was carried out. The insert metal employed in this study was experimentally home-made, Ag-Cu-Ti alloy. Influence of several bonding parameters of $Al_{2}$O$_{3}$SNCM21 joint was quantitatively evaluated by bonding strength test, and microstructural analyses at the interlayer were performed by SEM/EDX. From above experiments, the optimum bonding condition of the solid-state diffusion bonding of $Al_{2}$O$_{3}$/SNCM21 using Ag-Cu-Ti insert metal was determined. Futhermore, high temperature strength and thermal-shock properties of $Al_{2}$O$_{3}$/SNCM21 joint were also examined. The results obtained are as follows. 1. The maximum bonding strength was obtained at the temperature of 95% melting point of insert metal. 2. The high temperature strength of $Al_{2}$O$_{3}$/SNCM21 joint appeared to bemaximum value at test temperature 500.deg.C and the bonding strength with increasingtemperature showed parabolic curve. 3. The strength of thermal-shocked specimens was far deteriorated than those of as-bonded specimens. Especially, water-quenched specimen after heated up to 600.deg. C was directly fractured in quenching.

• Journal of Welding and Joining
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• v.27 no.4
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• pp.18-25
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• 2009

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• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.192-195
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• 2004

Surface friction welding, SFW, is a newly developed solid state welding technology for joining of thin metal sheets. Workpieces are joined by frictional heat, shear deformation and plastic flow generated by friction between the rotating tool and surface of the workpiece. The SFW is an economical and environmentally conscious technology with high joining speed and excellent properties, and is expected to be used widely in various industries in the near future.

• Proceedings of the KWS Conference
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• 1990.11a
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• pp.45-49
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• 1990

• Journal of Welding and Joining
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• v.30 no.5
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• pp.13-15
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• 2012

Stainless steels is widely used in various industries due to its high strength and excellent corrosion resistance. However, in the case of fusion welding for stainless steel, chromium deficiency layer produced by chromium carbide precipitation during welding process causes corrosion-resistance to be lower and formation of intergranular corrosion. It requires a inevitable complex procedure such as pre-heating and post-heating process etc. to prevent such weld defects. From this viewpoint, the new welding process such as a solid state welding method is suited for welding of stainless steels due to its advantages over the fusion welding. Therefore this paper intends to investigate the research trend on friction stir welding, one of solid state welding processes for stainless steels.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.41-41
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• 2009

To evaluate the applicability of dissimilar joining between Mg and Al alloys in automobile manufacturing process, solid state joining processes such as magnetic pulse welding(MPW), friction stir welding(FSW) and friction spot joining(FSJ) were attempted successfully. MPW process has been concentrated mainly on round section tube to tube and tube to bar welds. AZ31 Mg alloy has been successfully welded to pure Al A1070 as well as to Al alloy A3003. While, for friction stir welding of dissimilar sheet joints, AZ31B/A6061 with the thickness of 2mm were used and a square butt joint with a good quality was obtained at the conditions of 0.8mm/sec of travel speed and tool rotation speed of 850rpm. The maximum tensile strength of 179 MPa, which was about 80 % of the Mg base metal tensile strength, has been obtained. Finally, friction spot joining was attempted to make a dissimilar lap joint between AZ31(0.8mm) and A6061(1mm), while the joint exhibited the same level of tensile shear strength as that of similar Mg joint.