63414 2025 eng 1 11 296 article Elsevier BV 1 -- -- -- Grain boundaries (GBs) are common sites of failure in polycrystalline materials. Recently, a massive Zn segregation transition at Fe GBs was discovered and shown to act as a potent precursor of liquid metal embrittlement (LME) in the Fe-Zn system (Kamachali et al., Scripta Materialia 238 (2024) 115758). In this study, we elaborate on how temperature, GB type and the chemo-structurally coupled phase decomposition at the GB impact this segregation transition. CALPHAD and atomistic simulation data were utilized as inputs to conduct quantitative density-based thermodynamic modeling and phase-field simulations across various GBs, alloy compositions, and temperatures. We reveal that once the segregation transition becomes possible, the GB structural variation stabilizes spinodally formed Zn-rich phases within the GB region, with a higher tendency in disordered GBs. GB phase diagrams were constructed to identify and analyze the range of critical temperatures and alloy compositions associated with the segregation transition. The phase diagrams reveal that the miscibility gap for more disordered GB expands and, although the segregation transition is inevitable and occurs for all GBs, the barrier to triggering it is lower for more disordered GBs. Based on our thermodynamic analyses, potential processing modifications and GB engineering strategies for mitigating segregation-induced LME are thoroughly discussed. Acta Materialia 1359-6454 10.1016/j.actamat.2025.121134 urn:nbn:de:kobv:b43-634145 true journal-article https://www.elsevier.com/tdm/userlicense/1.0/ crossref doi-import 16.07.2025 1 Creative Commons - CC BY-NC - Namensnennung - Nicht kommerziell 4.0 International Yuki Ikeda Theophilus Wallis Robert Maaß Reza Darvishi Kamachali eng uncontrolled Thermodynamics eng uncontrolled Phase-Field Modelling eng uncontrolled Steels Ingenieurwissenschaften und zugeordnete Tätigkeiten 5 Werkstofftechnik 5.5 Materialmodellierung Material Verlagsliteratur Datei für die Öffentlichkeit verfügbar ("Open Access") Wissenschaftliche Artikel der BAM Materialdesign Bundesanstalt für Materialforschung und -prüfung (BAM) https://opus4.kobv.de/opus4-bam/files/63414/ThermodynamicsofLMEinFeZn_.pdf