Production of Multiprincipal Beta Ti-33Nb-33Zr Alloy through Arc Melting, Laser Additive Manufacturing and Severe Plastic Deformation

Abstract

In order to determine the effect of grain refinement, up to the sub-micrometer (ultrafine) range, on the mechanical properties and mechanical biocompatibility of multiprincipal ² Ti alloys, the effects of different processing routes on the microstructure and properties will be studied. Among biomaterials, metals play a significant role in structural applications, where capacity and resistance to different mechanical loads are required. The first metallic biomaterials were relatively inert materials, such as stainless steel and the alloys Co-Cr-Mo and Ti-6Al-4V, but with an elastic modulus much higher than that of human bone (E ~30 GPa). The ² Ti alloys have a modulus in the range of E = 42 to 80 GPa, and the multiprincipal BCC alloys open new perspectives for low modulus alloys. Subsequently, surface treatments were used to improve the interaction of the implant with the surrounding tissue. The present work aims to evaluate the production of the multiprincipal ² alloy Ti-33Nb-33Zr through arc melting, laser additive manufacturing and severe plastic deformation of ECAP (equal chanelling angular pressing). The project aims to compare the properties obtained with the observed microstructures, thus seeking the understanding of the processing influence on the microstructure and properties of the multiprincipal ² Ti-33Nb-33Zr equimassic alloy (wt.%). In this way, the microstructure will be characterized for the three processing routes: i) arc cast (AC), ii) produced by additive manufacturing through "laser powder bed fusion" (LPBF) and cast and subjected to iii) severe plastic deformation by ECAP; through the techniques of optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled with accessory techniques such as EDS (X-ray energy dispersive spectroscopy). The mechanical and physical characterization, for samples in as-cast (AC), ECAP and LPBF conditions, will be carried out through the determination of Vickers microhardness, the modulus of elasticity, E (GPa) via impulse excitation and the traction or compression, to determine mechanical properties. Thus, the objective of the present research is to evaluate the effect of grain refinement through different severe plastic deformation techniques on the performance of the multiprincipal ² Ti-33Nb-33Zr alloy as candidate for biomaterials for implants. (AU)