Effects of Precipitation morphology and Matrix texture on mechanical performance for high-boron steel

High-boron steel 304B7 has been selected as ITER vacuum vessel in-wall shielding (IWS) 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 (SEM), and electron backscatter diffraction (EBSD). 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.