2019 Fiscal Year Research-status 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 Institution | Tokyo Institute of Technology |
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Principal Investigator |
蔡 耀汪 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 – 2021-03-31
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| Keywords | microstructure / defects / interphase interfaces / interfacial strutcures / thermoelectric / half-Heusler alloys |
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| Outline of Annual Research Achievements |
In this research proposal, we are aiming to develop high performance half-Heusler thermoelectric materials that are also environmental friendly, low cost and stable at medium-high operating temperature range (i.e. 300-600 degree Celcius). In order to achieve the goal, firstly, we have fabricated a series of slightly off-stoichimetric quinary (Ti,Zr,M)Ni1.1Sn alloys,where M=V, Nb and Ta. The selection of the alloy composition is intended to maximise the introduction of multiscale microstructure, which includes microstructral features of different sizes, such as (a) the Ti-, Zr-, M- and vacancy point defects, (b) the nanoscopic clusters of point defect domains, (c) the various size of Ni-rich Heusler nanoprecipitates, and (d) planar defects created by the microscopic half-Heusler-half-Heusler phase domains. At this moment, we are trying to characterize the multiscale microstrucure with various microscopic techniques, such as SEM, EPMA, X-ray diffraction, TEM, HRTEM and STEM. Next, their thermoelectric properties will be measured with increasig temperature. This enables us to evaluate how to better control formation of the microstrutcure and eventually leads to the development of the best thermoelectric performance of half-Heusler alloys.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
The delay is mainly caused by the recent "stay-at-home" annoucement by the university due to the Covid-19 pandemic situation. Therefore, the laboratory is closed and we are unable to access all the characterization equipments.
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| Strategy for Future Research Activity |
The characterization of microstructure of the alloys will be continued and their respective thermoelectric properties will be evaluated accordingly. Next, we will identify the optimum combination of the multiscale microstructural features that results in the best thermoelectric performance half-Heusler alloys.
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| Causes of Carryover |
The main reason was due to the cancelling of a domestic and an international conferences. Therefore, in the next fiscal year, we plan to publish our research findings in high impact factor journals, and several well-recognised international and domestic conferences of thermoelectricity.
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