| Project/Area Number |
18K04744
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 26040:Structural materials and functional materials-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
CHAI Yaw Wang 東京工業大学, 物質理工学院, 特任准教授 (80455922)
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| Co-Investigator(Kenkyū-buntansha) |
木村 好里 東京工業大学, 物質理工学院, 教授 (90262295)
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | half-Heusler alloys / microstructure / interfacial structure / defects / nanoprecipitates / crystallography / thermoeletric / phase transformation / Half-Heusler alloys / Microstructure / Interfacial structure / Misfit dislocations / Nanoprecipitates / Nano-modulated structure / Ni-rich nanoclusters / Atomic disorders / misfit dislocations / thermoelectric / atomic disorders / interphase interfaces / interfacial strutcures / point defects / interphase interface / grain boundary / energy recycling / environmental friendly / thermoelectric materials / microstructure control / thermoelectric stability |
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| Outline of Final Research Achievements |
A series of environmentally friendly half-Heusler thermoelectric alloys containing multiscale microstructure (i.e., antisite point defects, the nanoscale and microscale spinodal-decomposed half-Heusler domains, the nanoscale full-Heusler nanoprecipitates of various sizes and morphologies) have ben successfully developed in this research. It was found that the high-temperature cyclic heat-treatment process and suitable amount of doping were two viable approaches to improve the overall thermoelectric performance of the alloys. The Nb-doped and cyclic-heat-treated half-Heusler alloy has shown the highest ZT to 0.91 at 752 K. The improvements are caused by the increment of power factor and the reduction of thermal conductivity. The former was due to the doping effects and the presence of the full-Heusler nanoprecipitates. The latter were closely associated with the diffuse interfacial structures among the multiscale microstructure upon the high-temperature cyclic heat-treatment process.
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| Academic Significance and Societal Importance of the Research Achievements |
Hence, this research aims at developing thermoelectric half-Heusler materials that can directly recycle waste heat energy from any high-temperature source. Most importantly, the energy generation is clean, involves no CO2 emission, environmentally friendly, low cost and stable at high temperature.
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