Zr segregation at grain boundaries modulating C15-like local chemical ordering in BCC TiZrNbTaV multi-principal element alloys

Local chemical ordering (LCO) is pivotal for strengthening multi-principal element alloys (MPEAs). This study demonstrates that Zr segregation at grain boundaries (GBs) governs the formation of C15-like LCO in TiZrNbTaV MPEAs. Combining hybrid Monte Carlo/Molecular Dynamics (MC/MD) simulations with experimental validation, we reveal that while Ta-V affinity drives C15-like LCO formation, it is Zr-Zr self-segregation, identified by deep learning, that predominantly modulates this formation. Systematic simulations and atomic-scale characterization across various GBs further show that this modulation by Zr segregation is GB-type-dependent. This mechanistic insight provides a theoretical basis for microstructural design in high-strength MPEAs.