LASER POWDER BED FUSION APPLIED TO Ti-42Nb ALLOY: MICROSTRUCTURAL REFINEMENT BY INDUCTION OF CONSTITUTIONAL UNDERCOOLING

• Grant number: 24/00402-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2024
• End date: February 29, 2028
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Rubens Caram Junior
• Grantee: Hugo André Magalhães de Azevedo
• Host Institution: Faculdade de Engenharia Mecânica (FEM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 18/18293-8 - Titanium alloys: phase transformations and additive manufacturing applied to obtaining functionally graded materials, AP.TEM

Abstract

Additive manufacturing (AM) of Ti alloys allows the production of components with almost unlimited geometric complexity. However, this manufacturing technique involves several issues that have not yet been fully resolved and among them is the tendency to form columnar grains, featuring an intense crystallographic texture. The resulting microstructural anisotropy negatively affects the mechanical behavior of the produced sample, generating asymmetric responses to mechanical stress. There are several ways to control the formation of columnar microstructure and one of them is based on the addition of alloying elements that increase the tendency towards constitutional undercooling. The Ti-42Nb alloy exhibits, depending on the processing conditions, a reasonable level of yield strength and a low elastic modulus. This work aims to investigate the role of adding Fe and Cu on the columnar-equiaxed transition of the Ti-42Nb alloy processed by the laser powder bed fusion technique. Sample preparation in an arc furnace and simulations using ThermoCalc® will allow establishing contents of alloying elements to be added to the Ti-42Nb alloy. Characterization of the samples will involve optical microscopy, scanning electron microscopy using EBSD (electron backscattered diffraction), X-ray diffraction, mechanical hardness, nanoindentation and tensile tests.