Development of low-modulus Ti-Ta alloys by in-situ synthesis during selective laser melting for implant applications
Igor Polozov, Victoria Nefyodova, А. И. Золотарев, Victoria Sokolova, Anna Gracheva, Anatoly Popovich
Abstract
This study investigates the influence of tantalum content (10, 15, and 20 wt%) and lattice structure on the microstructure, mechanical, and corrosion properties of titanium alloys produced by selective laser melting (SLM) using in-situ synthesis from individual element powders. Samples with various types of lattice structures (gyroid, split, and schwarz) and solid samples were examined. The use of the in-situ synthesis method allowed for the production of alloys directly during the SLM process from mixtures of titanium and tantalum powders. Metallographic studies and X-ray diffraction analysis showed that increasing tantalum content leads to an increase in the volume fraction of β-phase in the alloy structure. After heat treatment at 1100°C, a two-phase (α+β) structure with characteristic lamellar morphology is formed. It was found that increasing the tantalum content from 10 to 20 wt% leads to a decrease in the elastic modulus of the alloys from 118 to 102 GPa in tensile tests . The ultimate tensile strength reaches a maximum of 1102 MPa for the Ti-15Ta alloy. The use of lattice structures allows for a further reduction in the elastic modulus to 10–19 GPa, depending on the lattice type. Electrochemical tests showed high corrosion resistance for all investigated alloys, with the best pitting resistance basis indicators for Ti-10Ta (3.270 V) and Ti-15Ta (3.075 V). The results of the study demonstrate the potential of using Ti-Ta alloys with lattice structures, obtained by in-situ synthesis during SLM, for biomedical applications , particularly for the manufacture of implants with mechanical properties close to those of bone tissue.