1989 Fiscal Year Final Research Report Summary
IMPROVEMENT OF JOINT EFFICIENCY FOR FUNCTIONAL MATERIALS
| Project/Area Number |
62420049
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
溶接工学
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| Research Institution | Osaka University |
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Principal Investigator |
KIKUCHI Yasushi OSAKA UNIVERSITY, WELDING RESEARCH INSTITUTE, ASSOCIATE PROFESSOR, 溶接工学研究所, 助教授 (90005405)
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| Co-Investigator(Kenkyū-buntansha) |
KURODA Toshio OSAKA UNIVERSITY, WELDING RESEARCH INSTITUTE, INSTRUCTOR, 溶接工学研究所, 助手 (00107096)
IKEUCHI Kenji OSAKA UNIVERSITY, WELDING RESEARCH INSTITUTE, ASSOCIATE PROFESSOR, 溶接工学研究所, 助教授 (10030058)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Stainless Steel / Titanium Alloy / Composite / Sintered Alloy / Shape Memory Effect / Fusion Welding / Diffusion Welding / Friction Welding |
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| Research Abstract |
A wide variety of ferrous and non-ferrous materials of high functions have been bonded by the fusion welding and solid state bonding, and the microstructure of joints have been investigated in order to reveal the controlling factor of the joint efficiency and to develop the measure for its improvement. Results obtained are summarized as follows: 1. The fusion welding of stainless steels SUS304, SUS316 and SUS329JI has been systematically investigated with particular reference to the effects of welding atmosphere and heat cycle on the weldability and joint efficiency. As to the atmosphere, the welding parameters for realizing good weldability were determined in high pressure atmosphere up to 6 MPa, and the fracture toughness of weld metal was examined as a function of the partial pressure of oxygen. The weld heat cycle was found to have strong effects on the grain boundary segregation of P, which accelerated the intergranular stress corrosion cracking significantly. 2. The microstructur
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e of the weld heat affected zone of Ti-6Al-4V alloy was investigated to interpret the effects of the weld heat cycle on the mechanical properties and hydrogen induced cracking. 3. In order to apply the diffusion bonding to Al/Al_2O_3 and Al/SiC composites, the effects of surface treatments and intermediate metals on the bond strength have been systematically investigated. The surface treatment of electropolishing and the iritermediale metal of Al-Mg-Cu alloy were found to improve the bond strength, and their effects were discussed in relation to the wetting of the fiber by the intermediate metal. 4. For the friction welding of the Cu-W sintered alloy to copper, the effects of W content on the behavior of welds and the microstructure have been examined to explain controlling factors of the joint efficiency and its mechanism. 5. The fusion welding of NiTi alloy with shape memory effect have been carried out in various atmospheres. Though sound weld beads were obtained in inert atmospheres, the microstructure of the weld obtained was quite different from that of the base metal, suggesting that the ghape memory effect of the joint was significantly degraded. 6. The effects of martenstic, bainitic and ferritic microstructures on the stress relief cracking has been investigated for HT80 steel. Less
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