Ⅰ. Studies on the mechanism of joining of dissimilar metals
Bonding of dissimilar metals by Vacuum Roll Bonding
Dissimilar metal bonding and its characteristics
- Spot welding of mild steel and aluminum
- Stud welding of similar and dissimilar metals
- Welding of high carbon steel
- Wear-resistant layer is formed by cladding resistance
WC powder film formation by resistance cladding method
Ⅱ. Study on Improvement of the character of the material surface by YAG laser irradiation
- Surface modification by grain refining of steel, stainless steel, copper and aluminum
- Improvement of wear resistance of titanium as a biomaterial
Nitridation of titanium surface by laser heat treatment
| Shielding gas:Ar=100% | Shielding gas:N2=100％ | |
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| surface |  |
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| Cross section |  |
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From the viewpoint of reduction of generation of wear debris in total hip arthroplasty, the purpose of improving the wear resistance of titanium materials, we have investigated the surface modification of titanium by laser beam heating.
Ⅲ. Study on heat resistant steels/ alloys and welds
Study on heat resistant steels/ alloys and welds
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| Creep damage behavior in welds of 9%Cr heat resistant steel |
Initiation and growth of creep cavity in 9%Cr heat resistant steel |
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Creep strength enhanced martensitic 9%Cr steel may rupture in the fine grain heat affected zone of cross-weld creep specimens along with significant drop of strength, however the failure mechanism has not yet been well clarified. The detailed microstructural observation of the creep degradation process from cavity initiation to macroscopic damage reveals that the creep cavity is initiated by the separation of sub-grain boundaries, while it is still remained to understand the driving factors to cause separation of sub-grain boundaries from the aspect of chemical segregation and mechanical stress conditions.
