| Project/Area Number |
60550500
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属材料(含表面処理・腐食防食)
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
ASAMI KATSUHIKO The Research Institute for Iron Steel and Othe Metals, Research Associate, 金属材料研究所, 助手 (20005929)
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| Co-Investigator(Kenkyū-buntansha) |
KAWASHIMA ASAHI The Research institute for Iron Steel and Othe Metals, Research Associate, 金属材料研究所, 助手 (50005964)
HASHIMOTO KOJI The Research Institute for Iron Steel and Othe Metals, Ass. Professor, 金属材料研究所, 助教授 (70005859)
SATO TAKEAKI The Research Institute for Iron Steel and Othe Metals, Technician
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Laser Treatment / Rapidly Quenched Alloy / Amorphization / Vitrification / Amorphous Alloy / Surface Alloy |
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| Research Abstract |
Preparation of amorphous alloys by laser surface treatment was tried using <CO_2> cw laser in order to conquer the difficulty of industrial application of amorphous alloys because of their shapes obtained by conventional methods.
1. It is important to prepare mother alloys whose compositions are well-controlled. Mother alloys which consisted of elements with quite different density and boiling temperature often showed sediment of heavier elements such as Ir and loss of oxidizable elements such as Si during alloying by melting in a furnace. A stepwise alloying method was most effective in order to avoid these phenomena.
2. The cross-sectioned surface of mother alloys thus obtained was scanned by a focused laser beam. Each bead was amorphized easily but it was difficult to convert the entire surface to amorphous state mostly because of the re-heating of overlapping beads and also because of low thermal conductivity of mother alloys. Composition change by preferred evaporation and oxidation was also sometimes observed under the applied conditions.
3. On incompletely vitrified specimens, a large number of cracks were observed. These cracks were rare on entirely amorphized surfaces or ductile substrate. Cracks were originated within crystalline mother alloy because of thermal stress and propagated to the laser terated layer. Some cracks were stopped at the interface between the crystalline and amorphous phases.
4. A Pd-Cu-Si alloy was completely vitrified and relationship between amorphization depth and energy input mode was measured. Hardness was also measured across the cross-section perpendicular to the surface. Hardness was lowered in the vitrified region.
5. When the entire surface of an alloy was completely vitrified, the surface amorphous alloys prepared by laser treatment showed almost the same electrochemical properties as those of amorphous alloy ribbons prepared by a rotating wheel method.
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