Investigation of the phases formed at the interface of Titanium Alloys with Controlled Stiffness Manufactured Via Laser Powder Bed Fusion

• Grant number: 24/10229-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: February 13, 2025
• End date: March 28, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Rubens Caram Junior
• Grantee: Gilberto Vicente Prandi
• Supervisor: Vicente Amigo Borras
• Host Institution: Faculdade de Engenharia Mecânica (FEM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Universitat Politécnica de Valéncia (UPV), Spain
• Associated to the scholarship: 22/10049-6 - Obtaining materials with controlled stiffness by additive manufacturing and heat treatments, BP.DD

Abstract

Titanium and its alloys offer a wide range of mechanical properties due to their physical metallurgy, allowing the obtaining of stiffness gradients through heat treatments in parts with or without compositional gradients. The Ti-42Nb alloy, belonging to the metastable ² alloys, is less susceptible to heat treatments, presenting a ductile microstructure with low mechanical strength and low elastic modulus. On the other hand, the Ti-5553 alloy, also metastable, is more sensitive to heat treatments, resulting in high tensile strength after aging at moderate temperatures. The selective laser melting technique (L-PBF) enables the combination of powders from the two alloys, creating microregions with different compositions and mechanical properties. The combination of two distinct titanium alloys leads to variable stiffness, and this approach has been explored to develop materials with improved properties. This study aims to investigate the interface regions of the precursor materials of the hybrid alloy, both before and after heat treatments, focusing on the formation of the alpha phase and the presence of phases such as the omega phase, which are not visualized by scanning electron microscopy. To achieve this goal, advanced sample characterization techniques are necessary, including the use of a Focused Ion Beam (FIB), followed by detailed analysis using transmission electron microscopy. Additionally, this study also aims to employ the Small Punch technique to further understand the mechanical properties of the different regions formed by the hybrid alloy. The Small Punch Test will be used to evaluate the tensile strength, ductility, and creep resistance of these regions, allowing for a more comprehensive analysis of the material's mechanical behavior. By combining advanced sample preparation techniques and detailed microscopic analyses with sensitive mechanical testing, this study aims to significantly contribute to understanding the structural and mechanical properties of the hybrid alloy under investigation.