Study on cyclic stress measurement method in high temperature environment using Ni-P-B plating

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06118
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Design engineering/Machine functional elements/Tribology
• Research Institution: Tottori University
• Principal Investigator: ONO Yuichi 鳥取大学, 工学研究科, 教授 (50335501)
• Co-Investigator(Kenkyū-buntansha): 森戸 茂一 島根大学, 学術研究院理工学系, 教授 (00301242)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 実験応力解析 / 応力・ひずみ計測 / めっき法 / 金属疲労 / 電子線後方散乱回折法

Outline of Final Research Achievements

First, nickel-base superalloys were plated with Ni-P-B and heat-treated at an ambient temperature of 350 to 450 oC. The grain size of the plating layer was determined by EBSD analysis and the relationship with the heating conditions was investigated. It was confirmed that grain growth was promoted as the heating time and temperature increased.
Next, cyclic loading tests were conducted at an ambient temperature of 400 oC using a nickel-base superalloy plated with Ni-P-B. The grain size increased as the strain amplitude increased. A similar tendency was also confirmed even when the number of cycles was increased.The particle size after this cyclic loading test is larger than the particle size when only heating is applied for the same time as the cyclic loading time. Therefore, it was found that the strain amplitude could be measured at an ambient temperature of 400 oC, if the relationship between the grain size and the loading conditions was calibrated in advance.

Free Research Field

材料力学，機械設計学

Academic Significance and Societal Importance of the Research Achievements

従来の手法では不可能である高温環境下（400℃程度）における微視的領域のひずみを金属薄膜の粒成長に着目することで計測できる見通しが得られた．したがって，今後，較正試験を実施すれば，粒径からひずみ振幅を計測することが可能となり，有限要素法などの計算結果の妥当性の検証にも利用でき，より安全な機械の設計に役立つといえる．さらに，この応力測定技術は，機械工学分野だけでなく，航空宇宙，土木分野など他分野や社会への波及効果も期待できる．