2003 Fiscal Year Final Research Report Summary
Development of fundamental processes of directional solidification of TiAl-base Alloy
| Project/Area Number |
13355027
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Structural/Functional materials
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
YAMAGUCHI Masaharu Kyoto Univ., Fac. Eng., Professor, 工学研究科, 教授 (90029108)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAMI Takashi Natl. Inst. Advanced Industrial Science & Technology, Researcher, 機械システム研究部門, 研究員
TETSUI Toshimitsu Mitsubishi Heavy Industries, LTD, Manager, 長崎研究所, 主任
ITO Kazuhiro Kyoto Univ., Fac. Eng., Research Associate, 工学研究科, 助手 (60303856)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Directional solidification / Seeding / TiAl-base alloys / Lamellar microstructure / Mechanical properties / Constraint deformation |
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| Research Abstract |
Mechanical properties of the lamellar microstructure of TiAl-base alloys are extremely anisotropic with respect to the lamellar orientation. However, if the lamellar microstructure can be aligned parallel to the growth direction, the resulting material should possess a good combination of mechanical properties. The seeding and directional solidification (DS) techniques were developed for the lamellar boundaries to be aligned parallel to the growth direction. The lamellar structure of a wide variety of TiAl-base alloys can be controlled using the techniques. DS ingots of these alloys exhibit an excellent combination of room temperature tensile properties and high temperature strength, in particular, creep strength. Attempts were made to increase the size and growth rate of DS ingots for larger-scale production of TiAl castings through seeding and directional solidification. In order to obtain information on the mechanical behavior of DS ingots under the state of stress with multi-components, compression tests of DS ingots with various lamellar orientations were made under the constraint imposed along a direction perpendicular to the loading axis. Such constraint was found to significantly increase the yield stress of DS ingots with intermediate lamellar orientations. Slip systems which operate under the constraint were examined and the results were found to be in good agreement with those of the deformation analysis based on the description of anisotropic elastic continuum.
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