| Project/Area Number |
11450261
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ENOKI Manabu The University of Tokyo, Graduate School of Engineering, Associate Professor, 大学院・工学系研究科, 助教授 (70201960)
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| Co-Investigator(Kenkyū-buntansha) |
KISHI Teruo National Institute for Materials Science, President (Researcher), 物質・材料研究機構, 理事長(研究職)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥13,900,000 (Direct Cost: ¥13,900,000)
Fiscal Year 2001: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥5,300,000 (Direct Cost: ¥5,300,000)
Fiscal Year 1999: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | Internietallies / Layered materials / Micro fracture / Fracture toughness / Crack propagation / Toughening mechanism / 力学特性 / 破壊機構 / 複合材料 |
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| Research Abstract |
Materials are recently requested to have various functions. Intermetallics which have excellent strength and oxidation resistance are expected as high temperature structural materials. However, their application in monolithic form is very limited because of their lack of ductility and brittleness. Layered materials with ductile metals and brittle intermetallics are expected to have novel properties, especially enhancement of fracture resistance in specific direction. One of the methods to fabricate these metals/intermetallics layered materials is a self-propagated high temperature synthesis, and we have investigated Ni/Ni-Al, Ti/Ti-Al and Nb/Nb-Al layered materials. However, microvoids which are produced in intermetallic layer during hot-press processing affect the fracture behavior and reduce the strength of materials. In the present research we have tried the fabrication of layered materials with fewer microvoids by thin metal sheets processing and the change of intermetallic phase by different processing conditions of heat temperature and pressure. Also the mechanical properties and fracture mechanism of layered materials were investigated as well as the processing for excellent layered materials. Layered materials of Ni/Ni-Al with different thickness of metal layer and different intermetallic phase were successfully fabricated by self-propagating high temperature synthesis using hot-press from thin metal sheets of Ni and Al. The change of intermetallic phase gave the increase of both tensile strength and elongation. Crack propagation behavior in these materials was evaluated, and the criterion for crack direction whether a crack propagates straightly or deflects laterally was proposed using the analysis of stress field around crack tip.
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