Evaluating the irradiation hardening of reactor pressure vessel steels by nanoindentation hardness test and micropillar compression test. Issue 12 (2nd December 2022)

• Record Type: Journal Article
• Authors: Zheng, Yuyang; Geng, Diancheng; Yu, Hao; Kondo, Sosuke; Kimura, Akihiko; Yuya, Hideki; Kasada, Ryuta
• Is Part Of: Journal of nuclear science and technology. Volume 59:Issue 12(2022)
• Page Start: 1507
• Page End: 1518
• Publication Date: 2022-12-02
• Subjects: Mechanical property -- irradiation -- post irradiation examination -- reactor vessel steel -- nanoindentation -- micropillar -- hardness; Nuclear engineering -- Periodicals; Nuclear physics -- Periodicals; Nuclear energy -- Periodicals; 621.4805
• DOI: 10.1080/00223131.2022.2067258
• Languages: English
• ISSNs: 0022-3131

Abstract

ABSTRACT: Ultra-small testing technologies (USTTs), such as nanoindentation hardness tests and micropillar compression tests, can be potentially used to measure the mechanical properties of irradiated materials. However, the hardness and yield strengths of USTTs are different from those of standardized methods on bulk samples. In addition, irradiation-induced defects can affect the size dependence on the mechanical properties. This study examined A533B reactor pressure vessel steels before and after 5 MeV electron irradiation using USTTs. The depth dependence of the nanoindentation hardness was analyzed using the Nix-Gao model to evaluate the bulk-equivalent nanoindentation hardness and confirm its good linear relationship with the Vickers hardness. The compression yield strength was evaluated with a truncated square pyramid shape micro-pillars where the edge length ( d ) of the top surface and the height ( L ) of the micropillars were made similar: ( d, L ) = (1, 2), (2, 4), (3, 6), (4, 8), and (8, 16) in μm. The size dependence of the yield stress in the micropillars has a minimum at d = 2 µm, which remained unaffected by electron beam irradiation up to 22 mdpa. The average yield stress of the d = 4 and 8 µm specimens was similar to that of the bulk tensile specimens. ABSTRACT: uf0001