Effects of Short-Range Chemical Ordering on Thermodynamic Calculations of the High-Entropy Alloy NiCoCr.

• Grant number: 25/06530-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Pedro Augusto Franco Pinheiro Moreira
• Grantee: João Paulo Passos da Cunha
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 22/02770-7 - Integrated Computational Materials Engineering ICME: applied to modeling, production, characterization and testing high entropy alloys, AP.PNGP.PI

Abstract

This scientific initiation project investigates the effects of short-range chemical ordering (SRO) on thermodynamic calculations of the NiCoCr high-entropy alloy (HEA). While high-entropy alloys typically exhibit near-random elemental distributions, recent studies suggest certain elements may form localized organizational patterns that influence mechanical and thermal properties. The primary objective is to determine which solid phases remain stable under varying pressure and temperature conditions while accounting for SRO effects.The research will employ molecular dynamics simulations using machine learning-derived interatomic potentials (ML-IAPs) to achieve more realistic SRO modeling. Investigated crystal phases will include face-centered cubic (FCC), hexagonal close-packed (HCP), and sigma configurations. Computational cells will be generated both with and without SRO to calculate Gibbs free energy across different thermodynamic conditions.The methodology incorporates reversible variation methods to track phase transitions and establish solid-phase diagrams. Expected outcomes include identifying specific conditions where SRO influences phase stability in NiCoCr, thereby enhancing understanding of this material's structural and mechanical properties. (AU)