2021 Fiscal Year Final Research Report
Multiscale microstructure engineering and the development of high performance, environmental friendly, low cost and thermally stable half-Heusler thermoelectric materials
| 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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| Keywords | half-Heusler alloys / microstructure / interfacial structure / defects / nanoprecipitates / crystallography / thermoeletric / phase transformation |
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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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| Free Research Field |
Materials Science and Engineering
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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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