Production and Characterization of High Toughness HEAs by Genetic Algorithm

• Grant number: 23/04907-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: May 01, 2023
• End date: February 28, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Francisco Gil Coury
• Grantee: Caroline Binde Stoco
• 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): 23/14613-6 - Optimization of High Entropy Alloys using Artificial Intelligence methods, BE.EP.MS

Abstract

High Entropy Alloys (or HEAs) are a new class of metallic alloys whose main characteristic is to have three or more main elements. Its development seeks to achieve unique properties combinations, creating materials with optimized performance for specific applications. There is great interest in the development of high-toughness HEAs for structural applications. The vast field in which these alloys exist generates the need to use high-performance computational methods for the selection of compositions that meet the requirements of interest quickly and efficiently. The selected strategy for this project is the use of genetic algorithms integrated with the CALPHAD method. Through cross-over and mutation processes, genetic algorithms form new alloy generations with properties closer to the parameters of interest each time. The CALPHAD method, in turn, is of fundamental importance for the prediction of the phases that will be in equilibrium as a function of composition and temperature. The combination of these tools allows the selection of high-toughness HEAs, whose optimized characteristics include: 1) high intrinsic yield strength from solid solution hardening, 2) high potential for strength enhancement via grain refining, and 3) twinning effect and phase transformation (TWIP/TRIP). From this method, the 3 alloys with the highest hardening components will be selected, produced in small 50 g buds by casting in an electric arc melting furnace, processed and characterized by techniques such as 1) Scanning Electron Microscopy (SEM), including Energy Dispersive Spectroscopy (EDS) and possibly Transmission Electron Microscopy (TEM) to determine whether predicted properties have been achieved; 2) Differential Scanning Calorimetry (DSC) to verify eventual transformations in the alloy and 3) Vickers nanohardness and microhardness to evaluate the potential of each composition. Based on the results, the most promising alloy will be produced in 2 kg to 4 kg ingots, being characterized by tensile tests at room temperature, whose resulting curves will be compared with the nanoindentation curves to extract information such as the alloy work hardening capacity and elastic properties. The experimental information will be used to validate the fundamental models used to design the selected HEAs, allowing a deeper understanding of the physical metallurgy of high entropy alloys. In addition, the integration of the genetic algorithm with the CALPHAD method will also be evaluated regarding its applicability for the selection of compositions of interest, which may eventually be adapted for the selection of a wide range of alloys, not only those considered of high entropy.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

STOCO, CAROLINE BINDE; CASSAR, DANIEL ROBERTO; SANTANA, GEOVANA LIRA; KAUFMAN, MICHAEL; CLARKE, AMY; COURY, FRANCISCO GIL. Optimizing toughness in high entropy alloys using a genetic algorithm: A combined computational and experimental approach. MATERIALS TODAY COMMUNICATIONS, v. 41, p. 9-pg., 2024-12-01. (21/12044-9, 22/01327-2, 23/04907-2, 22/02770-7)