Nanostructure creation of Fe2VAl based alloy by introduction of nitride interface for thermoelectric application

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05100
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26030:Composite materials and interfaces-related
• Research Institution: Kyushu Institute of Technology (2021-2022); Nagoya Institute of Technology (2020)
• Principal Investigator: Watanabe Kosuke 九州工業大学, 環境エネルギー融合研究センター, 特任助教 (40617007)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ナノ構造化 / 熱伝導率低減 / ホイスラー合金 / 熱電材料 / 異相界面 / 窒化物 / メカニカルグラインディング / クライオミリング

Outline of Final Research Achievements

We have developed a methodology for incorporating an AlN interface as an anti-diffusion layer near the crystal grains of Fe2V1-xAl1+x. This involved the transformation of Fe2V1-xAl1+x+y powder into Fe2V1+xAl1-x/AlN composite particles through a specified nitriding process, followed by sintering of these particles. In order to enhance the reduction of thermal conductivity, the Fe2V1-xAl1+x+y powder was subjected to pulverization using MG and cryo-milling techniques, resulting in a particle size reduction to 3.9 μm. Subsequently, successful reduction of grain size to 1.5 μm was achieved in the sintered compact of Fe2V1+xAl1-x+y. Furthermore, the introduction of the AlN phase enabled a simultaneous reduction of thermal conductivity by more than 30% and suppression of grain growth during sintering. However, it should be noted that future efforts should focus on controlling compositional deviations during the milling and nitriding processes, as well as improving electrical properties.

Free Research Field

複合材料・界面

Academic Significance and Societal Importance of the Research Achievements

延性が高い合金のミクロンオーダーへの粉砕は困難であるが、本研究ではMGやCM、さらには窒化処理などを効果的に組合せ、4 μm以下まで粒径を減少させることができた。また、このような高強度で実用的な材料に関して、ナノ構造化および熱的安定性を同時に達成した例はなく、今後の発展が大いに期待できる。今後は母相組成をチューニングし、実用的な熱電材料として研究開発を進めていく。