TY  - JOUR
A1  - Ikeda, Yuki
A1  - Wallis, Theophilus
A1  - Maaß, Robert
A1  - Darvishi Kamachali, Reza
T1  - Thermodynamics of grain boundary segregation transition and their relevance for liquid metal embrittlement in Fe-Zn system
JF  - Acta Materialia
N2  - 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.
KW  - Thermodynamics
KW  - Phase-Field Modelling
KW  - Steels
PY  - 2025
UR  - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634145
DO  - https://doi.org/10.1016/j.actamat.2025.121134
SN  - 1359-6454
VL  - 296
SP  - 1
EP  - 11
PB  - Elsevier BV
AN  - OPUS4-63414
LA  - eng
AD  - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER  -