Analysis of the influence of heat treatments and alloying elements on the microstructure and hardness of the Ni-15Nb-M system

• Grant number: 22/08627-1
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: December 01, 2022
• End date: March 31, 2023
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Conrado Ramos Moreira Afonso
• Grantee: Mariana Santos Pereira
• Supervisor: Vicente Amigó Borrás
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: Universitat Politécnica de Valéncia (UPV), Spain
• Associated to the scholarship: 20/06392-1 - Influence of the alloying elements addition on the microstructure and hardness of Ni-Nb-M alloys system (M = Al, Ti, Cr, Fe), BP.IC

Abstract

The present project aims to study the effect of heat treatments on high performance ternary alloys of the Ni-15Nb-M system, where M = Al, Ti, Cr or Fe in different weight percentages. From the composition and the heat treatment, precipitation of secondary and hardening phases related to the different alloying elements of the Ni-15Nb system are formed, which are related to the mechanical and corrosive performance of the alloys. After the heat treatments (solubilization at T = 1150 °C/1 h and aging at T = 750 °C and t = 1 h, 10 h, 30 h and 100 h), the microstructure (composition and percentage of the phases formed and grain size) will be evaluated using advanced microscopy techniques such as EBSD microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Subsequently, the intrinsic mechanical properties of the matrix (³-Ni), and also of the secondary hardening phases - gamma prime (³') and delta (´) -, will be studied using the nanoindentation technique, which will provide results of the elastic modulus and hardness according to the microstructure formed after heat treatments. Therefore, the aim is to correlate the microstructural and mechanical characteristics obtained through the techniques mentioned above and then predict the efficiency of the alloys according to their alloying elements. (AU)