Interdiffusion in V aluminides and determination of kinetics parameters

• Grant number: 22/06285-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2022
• End date: January 31, 2024
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Gilberto Carvalho Coelho
• Grantee: Vitória de Melo Silveira
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

The study of kinetic phenomena is important in order to understand physical-chemical and mechanical properties of materials, such as creep, corrosion and oxidation resistance. One of these phenomena is the diffusion, whose processes are widely explored in many industrial sectors, for example in surface heat treatments to improve some properties. The deposition of oxidation protective coatings for structural materials that are used in high temperature environments is necessary for most of these materials, as they must have both adequate mechanical properties and good chemical resistance at these temperatures. Vanadium-containing alloys, which is a metal with a high melting point and low density (compared to other refractory/reactive metals), are examples of materials that meet these requirements when used with certain protective layers, for example aluminum. The present project aims to determine kinetic parameters, more specifically growth constants and interdiffusion coefficients, for vanadium aluminides. Al-V diffusion couples will be constructed by the pack cementation technique, at temperatures between 750 and 1000°C for times from 1 to 36 hours, during which the interdiffusion of the elements and the growth of diffusion products will occur. The coated substrates will be microstructurally characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The interdiffusion coefficients will be determined by the Wagner model, which can be used to estimate the thermal stability of the deposited coatings and to contribute to the construction of kinetic databases.