| Abstract Scope |
Tungsten-based alloys are promising plasma-facing materials for fusion reactors, but their performance is limited by embrittlement, recrystallization, and irradiation-driven degradation. Tantalum is a promising solute for W; however, its effect on grain-boundary segregation and grain-boundary-mediated deformation remains unclear. Here, we develop a transferable Graph Atomic Cluster Expansion (GRACE) interatomic potential for W–Ta using first-principles data generated through feature-information entropy maximization, enabling broad coverage of relevant atomic environments. We apply this potential to investigate how Ta concentration, temperature, and grain-boundary character influence shear-driven grain-boundary behavior. The simulations quantify key signatures of grain-boundary response, including segregation, mobility, shear coupling, defect activity, roughening, and stress evolution. The results clarify how Ta modifies grain-boundary migration and deformation mechanisms in W–Ta alloys under fusion-relevant conditions. |