2025/11/25 by Lyu, Guanlin, Sun, Yuguo, Gao, Panpan +1
Engineering · Materials Science · #FOS: Physical sciences #Fusion materials and technologies #Materials Science (cond-mat.mtrl-sci) #Nuclear Materials and Properties #Nuclear reactor physics and engineering
paper · doi:10.48550/arxiv.2511.20408
openalex publication_date 2025/11/25 · openalex created_date 2025/11/28 · openalex updated_date 2026/07/28
Elements with low thermal neutron absorption cross-sections are ideal for enhancing structural materials in nuclear systems. In this study, We systematically investigate the segregation and co-segregation behaviors of eleven elements at the Σ7(0001) twist grain boundary in yttrium and their effects on stability and strength. The Σ7(0001) grain boundary exhibits weakening, with fracture occurring preferentially along path I. Segregation energy calculations show that Si, Cu, Cr, Mo and Fe prefer interstitial sites, while others occupy substitutional ones. Si, Al, Zn, Cu, Mg and Fe stabilize the boundary, while Mo, Fe, Si, Cr, Cu, Nb and Ti strengthen it, with Si offering the most balanced improvement. Co-segregation studies reveal that Si induces the enrichment of other solutes at the boundary, promoting synergistic stabilization and turning embrittling elements (Al, Mg, Zn, Zr) into strengthening agents. Electronic structure analysis shows that Si-Y covalent bonds enhance electron localization, and Si+Mg co-segregation optimizes electronic distribution through metallic-covalent cooperation, significantly improving fracture resistance. The density of states analysis indicates new low-energy deep states in the Si, and Si+Al, Si+Mg systems, which lower grain boundary energy and improve stability. This study provides guidance for designing high-performance, low-neutron-absorption Y-based alloys.