Synthesis and Characterization of Multicomponent Alloys Based on the Cr-Nb System for High-Temperature Applications

• Grant number: 25/04108-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2025
• End date: August 31, 2028
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Carlos Alberto Della Rovere
• Grantee: João Gabriel da Cruz Passos
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 22/03139-9 - Design and production of multicomponent refractory alloys with optimized high-temperature oxidation properties, AP.PNGP.PI

Abstract

Refractory Multicomponent Alloys (RMAs) have garnered interest due to their potential as substitutes for Ni-based superalloys. The low corrosion resistance of refractory alloys usually prevents their practical use without protective coatings. However, RMAs protected by a CrTaO4 oxide show a promising path toward the production of corrosion-resistant refractory alloys for high-temperature applications. In alloys containing Nb, the CrNbO4 oxide has also demonstrated promising protective capabilties, but the performance of these alloys is still inferior to those with Cr and Ta. Considering the yet unrealized potential for producing refractory alloys protected by this type of rutile and the strategic importance of Nb for Brazil, this project proposes to develop and investigate Cr- and Nb-based alloys for applications in high-temperature corrosive environments. Initially, the project will focus on the binary Cr-Nb system and, if necessary, Cr-Nb-Ti, to determine the base composition with the greatest potential for rutile formation. Subsequently, RMAs based on this composition will be produced through gradual addition of other elements. The alloys will be produced through arc melting. For alloys with more than four elements, films will be produced using magnetron sputtering to be used as filters to define compositions of interest. Samples will undergo mechanical and corrosion testing. High-temperature corrosion, the project's primary focus, will be evaluated through thermogravimetric testing, tests in varied atmospheres, and hot corrosion tests. By the end, the project aims to generate data enabling the production of Cr- and Nb-based corrosion-resistant alloys, as well as a RMA composition applicable to high-temperature conditions. (AU)