Regensburg 2025 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 9: Poster
MM 9.10: Poster
Montag, 17. März 2025, 18:30–20:30, P1
Grain boundary transformation induced by boron segregation — Xuyang Zhou1, •Sourabh Kumar2, Siyuan Zhang1, Xinren Chen1, Baptiste Gault1, Gerhard Dehm1, Tilmann Hickel1,2, and Dierk Raabe1 — 1Max-Planck-Institut für Eisenforschung, Düsseldorf, 40237, Germany — 2Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, 12489, Germany
The segregation of solute atoms at grain boundaries (GBs) critically influences the mechanical properties of materials, including corrosion resistance and fracture toughness. This study examines structural transformations induced by minimal boron concentrations at Σ13 GBs in ferrite thin films. Two sample protocols were investigated: one with carbon as the sole solute and the other with carbon and boron co-segregation. Using ab initio calculations, we meticulously explored the competing Σ13 GB phases coexisting with defects and analyzed the energetics of solute segregation at the GB interface. A defect phase diagram was constructed to illustrate the influence of B concentration on GB structure evolution. We reveal that B segregation transforms the GB structure from flat to zigzag trigonal prisms by forming new chemical bonds, enhancing B-Fe bonding strength by 5%. This transformation doubles steel's fracture resistance and provides valuable insights into solute-driven GB phase evolution, contributing to innovative strategies for designing durable, high-performance steel.
Keywords: Phase transformation; Grain Boundary; Steel; Thermodynamics