Effects of precipitation morphology and matrix texture on mechanical performance for high-boron steel

High-boron steel 304B7 has been selected as International Thermonuclear Experimental Reactor vacuum vessel in-wall shielding material. Due to the brittle fracture issues of high-boron steel, there are still many challenges to overcome in engineering-scale production. Based on the preparation process...

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Bibliographic Details
Main Authors: Benxian Song, Xiang Geng, Chunyi Xie, Haiyang Fu, Jing Wang, Weijun Wang, Qiang Qi, Hai-Shan Zhou, Guang-Nan Luo
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:Nuclear Fusion
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Online Access:https://doi.org/10.1088/1741-4326/adf900
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Summary:High-boron steel 304B7 has been selected as International Thermonuclear Experimental Reactor vacuum vessel in-wall shielding material. Due to the brittle fracture issues of high-boron steel, there are still many challenges to overcome in engineering-scale production. Based on the preparation process of engineering applications, it is necessary to explore the material preparation of hot isostatic pressing (HIP) and melting-casting. In this study, sample 304B7-A was prepared by HIP, and sample 304B7-B was prepared by melting-casting. The research focuses on the morphology of precipitation and the evolution of matrix texture, analyzing their relation to the macro-mechanical properties of high-boron steel. This study comprehensively analyzes the results of Vickers hardness, tensile test, scanning electron microscope, and electron backscatter diffraction. The findings indicate that the phases of 304B7-A are finer and more dispersed, resulting in a synergistic effect of grain refinement and grain boundary pinning, which significantly enhances the mechanical properties. Texture analysis reveals that during plastic deformation, γ -Fe grains rotate towards the {110}<111> ∥ loading direction, and the {110}<001> texture is effectively retained in the samples. These findings provide theoretical foundations for optimizing high-boron steel’s mechanical properties, and make great significance for expanding its engineering applications in the nuclear industry.
ISSN:0029-5515