Production and Characterization of Precipitation-Hardened Ni-Co-Fe-Cr-Al-Ti High-Entropy Alloy by High-Throughput CALPHAD

• Grant number: 23/06725-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: May 31, 2026
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Francisco Gil Coury
• Grantee: Ana Victória Alves Cardoso de Oliveira
• 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
• Associated scholarship(s): 25/10806-0 - X-Ray Tomography Characterization of Surface Remelted Precipitation-Hardened High-Entropy Alloys, BE.EP.IC

Abstract

The project aims to utilize the high-throughput CALPHAD method along with precipitation hardening models to select a composition of an alloy preferably containing Ni-Co-Fe-Cr-Al-Ti (along with possible additional elements) that exhibits good mechanical strength and ductility. The chosen composition will be produced and characterized. The Ni-Co-Fe-Cr-Al-Ti system comprises various alloys with a face-centered cubic (CFC) structure that can be hardened by L12 precipitates. The inclusion of elements in this system allows for the prediction of the antiphase boundary energy (ECAF), a crucial factor in precipitation hardening calculations. However, given the complexity of this precipitation hardening mechanism, the high-throughput CALPHAD method is required to efficiently map large composition ranges. This tool will be applied to identify a suitable composition within the system, which will subsequently be produced and characterized. The proposed activities involve selecting the composition using precipitation hardening models and the high-yield CALPHAD method. The selected alloy will be produced through arc-melting furnace casting, followed by processes such as homogenization, cold rolling, solution treatment, and aging at different times and temperatures. The samples will be characterized using scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD), in addition to undergoing hardness testing. A test specimen will be subjected to mechanical tests, such as tension, to evaluate the mechanical properties of the alloy. The obtained results will be presented at undergraduate research conferences and, whenever possible, published in indexed international journals.