Takahiko Shindoh

Stress Singularity for Free-Edge of Interface of Copper/Aluminium Friction Welded Joint with Intermetallic Compounds.

The friction welding for copper and aluminium is useful to minimize the diffusion thickness at the interface between copper and aluminium. The minimization of diffusion thickness is required for maintaining the joint strength. However, it is well known the growth of brittle intermetallic compounds, such as CuAl2, CuAl and Cu9Al4, during the use at high-temperature. The effect of intermetallic compound layers on joint strength characteristics has not fully been clarified. In this study, elastic properties of intermetallic compound layers were investigated using depth-sensing micro-indentation technique. And stress singularities at the intersection of free surfaces and the interface between copper and aluminium were investigated using singular analysis. It was informed that the no free-edge stress singularities existed at the nelghborhood of apex angles of 55°and 125°. It was also confirmed using finite element analysis that the reduction of stress concentration could be observed by paying attention to the condition of no free-edge stress singularities in case of the copper and aluminium friction welded joint with brittle intermetallic compound layers.

Effect of Interface Shape of the Strength for Carbon Steel/PMMA Adhered Joint

The adhered joint composed of polymer and metal is a useful and practical method to take advantage of the both material properties. However, there are some basic problems for the material mismatch due to the different Youngs modulus. Inthis study, the stress singularity at the intersection between the free surface and the interface betweenpoly-methyl-methacrylate (PMMA) and structural carbon steel (JIS SS400) was analyzed to clarify the joint strength using a finite element method. As a result, the stress singularity was found above 130 degree of PMMA apex angle and between 35 and 41 degree of PMMA apex angle. In this experiment, it was confirmed that the no free-edge stress singularity was useful conditions to insure the reliability of bending strength for the adhered joint composed of SS400 and PMMA.

Development of Glass-coated Electrodes. Study on functional bonding (Report 1).

In high frequency electrodes that are composed with a metal substrate and a dielectric coating layer, it is important to clearify the bonding between the metal substrate and the dielectric coating layer and to produce a low dielectric coating layer for electric discharge parts.In this study, the low dielectric coating material is selected the borosilicate glass and the metal substrate is selected the 18Cr-stainless steel by the thermo-electric analysis based on the thermal expansion coefficient of the glass. And it is investigated that the effect of residual stress in the glass in evaluated by thermo-elastic analysis and experiments. Also the interface between the metal substrate and the coating layer is observed from the point of bonding mechanism and is mesured the permittivity in the glass-coated components. As a result, it is showed that the coating layer in thickness of four milimeter could be obtained over the 18Cr-stainless steel by multi-layer coating technique.