Interfacial control of Co-based superalloy for new forging process

2022 Fiscal Year Final Research Report

• Project/Area Number: 18H01742
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Tohoku University
• Principal Investigator: Oikawa Katsunari 東北大学, 工学研究科, 教授 (70356608)
• Co-Investigator(Kenkyū-buntansha): 上島 伸文 東北大学, 工学研究科, 助教 (10733131)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 熱間加工 / 超合金 / 動的再結晶 / ミクロ組織 / 析出強化

Outline of Final Research Achievements

The effect of microstructure on the hot workability of Co-based superalloys, which are expected as new heat-resistant alloys, was investigated. We prepared samples in which different size of the γ' phase particles was precipitated for the hot compression. The smaller the γ' phase particles, the smaller the compressive load in Co-Al-W-based alloys, and the larger the γ' phase particles, the smaller the compressive load in Co-Al-W-Ni-Ti-Ta-B alloys. This suggests that the precipitation strengthening mechanism varies with the alloy system. The size of the residual γ' phase particles after compression was became significantly larger. This suggest that the γ' phase particles grow during the forging process. It is also clear that the γ' phase particles became incoherent with the matrix phase.

Free Research Field

材料加工

Academic Significance and Societal Importance of the Research Achievements

Co基超合金は，次世代の耐熱合金として期待されている．強化粒子であるγ'相が析出しているときの，熱間変形挙動やその後のミクロ組織変化については，殆ど研究されてこなかった．本研究では，母相粒径やγ'相粒子サイズが加工荷重に大きな影響があることを明らかにし，かつ，加工中に析出粒子が粗大化し非整合化することを見出している．以上の知見は，最適加工条件を明らかにすること役立つ．