A Modified Embedded-Atom Method Potential for a Quaternary Fe-Cr-Si-Mo Solid Solution Alloy

Abstract

Ferritic-martensitic steels, such as T91, are candidate materials for high-temperature applications, including superheaters, heat exchangers, and advanced nuclear reactors. Considering these alloys’ wide applications, an atomistic understanding of the underlying mechanisms responsible for their excellent mechano-chemical properties is crucial. Here, we developed a modified embedded-atom method (MEAM) potential for the Fe-Cr-Si-Mo quaternary alloy system—i.e., four major elements of T91—using a multi-objective optimization approach to fit thermomechanical properties reported using density functional theory (DFT) calculations and experimental measurements. Elastic constants calculated using the proposed potential for binary interactions agreed well with ab initio calculations. Furthermore, the computed thermal expansion and self-diffusion coefficients employing this potential are in good agreement with other studies. This potential will offer insightful atomistic knowledge to design alloys for use in harsh environments.

Radiation-Induced Defect Formation Kinetics in Inconel–Cu Multimetallic Layered Composites

“…A microcanonical (NVE) ensemble was employed for the cascade simulation over a 20-picosecond duration, utilizing a variable time-step algorithm to optimize numerical efficiency. The PKA selection process is governed by a successive cascade algorithm, whereby a solitary atom within a stipulated spherical volume is designated as the PKA and endowed with the requisite energy of 10 keV to initiate bombardment processes [44][45][46][47][48]. The evolution of the collision cascade events happens in four stages, namely, the initial collision, thermal spike (TS), ballistic mixing, and annealing.…”