Fast and transferable interatomic potential for alloys, compounds, and hydrides in the Fe–Cr–Ni–Ti–H system

Fast and transferable interatomic potentials are in high demand for atomistic simulations of multicomponent systems, particularly those involving compounds and hydrides. In this work, we present a new classical interatomic model for the Fe–Cr–Ni–Ti–H system in the form of an angular-dependent potential (ADP). The potential accurately reproduces key thermodynamic and kinetic properties, phase stability, elastic properties, defect energetics and migration behavior in different materials: alloys, compounds, and hydrides. Benchmark tests demonstrate that the reported classical potential achieves an accuracy comparable to that of modern machine-learning interatomic models. At the same time, its classical functional form provides high computational efficiency, making the potential well suited for a variety of large-scale simulations involving millions of atoms over extended time scales. As representative examples, we present two large-scale atomistic simulation studies. The first examines strain-induced transformations near a crack tip in Fe-based alloys. The second case investigates hydride formation in FeTi compounds upon exposure to a molecular hydrogen environment. These examples demonstrate that the developed ADP model is capable of capturing complex phenomena in technologically relevant materials.