Understanding the deformation mechanisms of CrCoNi concentrated alloys with additions of a fourth element

• Grant number: 23/06700-6
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: September 01, 2023
• End date: August 31, 2024
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Claudemiro Bolfarini
• Grantee: Pedro Henrique Fernandes Oliveira
• Supervisor: Ed Pickering
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: University of Manchester, England
• Associated to the scholarship: 21/12589-5 - Understanding strength and deformation of CrCoNi concentrated alloys with additions of a fourth element, BP.PD

Abstract

Single-phase Multi-Principal Element Alloys (MPEAs) are a subclass of the more well-known High Entropy Alloys (HEAs). Those containing Cr, Co and Ni can display high mechanical strength, excellent corrosion resistance and thermal stability depending on the composition. In this class of material, the solid solution strengthening (SSS) provides important contributions to their excellent mechanical properties, as strengthening in order of hundreds of MPa can be achieved. Cr-Co-Ni alloys are emerging as a potential new class of material for structural applications; however, several modifications of the equiatomic compositions have not yet been tested. Therefore, to have models identifying the underlining factors that control the SSS would be a tool to guide the property-oriented design alloys. There are at least three models in the literature proposing to predict the effect of the SSS component in High Entropy Alloys. These models are fundamentally contradictory: they diverge in which component exerts the greatest influence in SSS: the difference in electronegativity or the difference in the atomic radius. In this context, this work aims to investigate and elucidate the most reasonable of the three models. Hence, in this work seven different alloys will be studied, with compositions that would induce different balances of SSS based on the existing models, meaning that the different fourth elements will change differently both contributions, for example while Palladium is shown to have a large impact in the atomic radii change, Vanadium have a more pronounced electronegativity change. The alloys will be produced and characterized in order to provide scientific contribution to the understanding of the main contributing factor for the SSS mechanism for CrCoNi MPEAs and HEAs. Furthermore, the most promising compositions will also have their deformation mechanisms operating under tension thoroughly investigated experimentally. (AU)