Re Enhancement Effects: Development of a Reaxffnialre Reactive Force Field for Ni-Based Superalloys

Abstract

A novel reactive force field, ReaxFFNiAlRe-S23, is developed specifically for simulating the mechanical behavior of Ni-Al-Re systems to understand the role of Rhenium (Re) in Ni-based superalloys. Based on density functional theory (DFT) calculations, ReaxFFNiAlRe-S23 accurately captures the interatomic interactions and energetics of  Ni-Al-Re structures, with a focus on the role of Re additions. Through parameterization and validation, this force field demonstrates exceptional fidelity in reproducing DFT-derived properties, including energies, geometries, and charge distributions, thereby providing a robust platform for the computational exploration of alloying effects. Utilizing ReaxFFNiAlRe-S23, we conducted tensile molecular dynamics simulations to investigate the impact of various Re additions on the tensile strength of Ni/Ni3Al structures. Results demonstrate that Re significantly enhances the mechanical properties, especially when strategically positioned around dislocation cores within the alloy matrix. This finding supports the hypothesis that dislocation hindrance, rather than interface strengthening, is the primary mechanism at play. This improvement is attributed to Re's ability to induce localized atomic disorder, effectively resisting dislocation propagation under external deformation and thereby augmenting the alloy's tensile resilience. Additionally, the evolution of atomic charges was also examined, providing insights into the electronic factors contributing to the mechanical strengthening mechanisms. These findings underscore the critical importance of Re addition in terms of the spatial distribution in the Ni matrix for optimizing the mechanical performance of Ni-based superalloys.  ReaxFFNiAlRe-S23 emerges as a powerful computational tool for advancing understanding of alloying effects in superalloy, which should facilitate the design of materials with mechanical properties tailored for high-temperature applications.

Keywords: Reactive force field (ReaxFF), Embedded atom method (EAM), Density functional theory (DFT), Ni-based superalloy, Rhenium (Re)