Crystal orientation dependence of irradiation-induced hardening in structural materials for nuclear applications

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15477
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 31010:Nuclear engineering-related
• Research Institution: The University of Tokyo
• Principal Investigator: YANG Huilong 東京大学, 大学院工学系研究科(工学部), 特任助教 (10814254)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 照射硬化 / 結晶方位 / 変形 / ジルコニウム基合金 / 燃料被覆管材料

Outline of Final Research Achievements

Anisotropic effects of irradiation-induced hardening in nuclear engineering materials with texture in microstructure, such as fuel cladding in nuclear power reactors, were studied with the assistance of the combined utilization of ion-accelerator, nano-indentation testing and electron backscatter diffraction analysis. The effects of the microstructural features such as lattice structure, grain boundary, secondary phase particles on the anisotropy of hardening were investigated. Strong crystal orientation dependent irradiation hardening is confirmed in hcp-latticed Zr alloys, whereas in bcc-latticed ODS steel, the occurrence of anisotropic behaviors of irradiation hardening is more likely to be influenced by the lamella grain structure rather than the crystal orientation. The mechanism behind the anisotropic effects of irradiation-induced hardening is linked with the interaction among microstructure-irradiation defects-deformation in various nuclear engineering materials.

Free Research Field

原子力工学

Academic Significance and Societal Importance of the Research Achievements

照射誘起硬化は炉内部材の経年劣化及び高性能材料開発において重要な指針であるが、これまでの先行研究では、照射硬化は材料がランダムな微細組織を持つという仮定の下で研究開発が進められてきた。しかし、実材料における微細組織は完全にランダムではなく、照射硬化が不均一に生じる。このため、本研究知見は、これらの原子炉構造材料の経年劣化をより正確に評価するために活用され、材料寿命管理の高度化に資する知見を提供する。さらに、これらを材料開発にフィードバックすることで高性能材料開発への応用も期待できる。