Designing the microstructural constituents of an additively manufactured near β Ti alloy for an enhanced mechanical and corrosion response

Additive manufacturing of near beta-type Ti-13Nb-13Zr alloys using the laser powder bed fusion process (LPBF) opens up new avenues to tailor the microstructure and subsequent macro-scale properties that aids in developing new generation patient-specific, load-bearing orthopedic implants. In this work, we investigate a wide range of LPBF parameter space to optimize the volumetric energy density, surface characteristics and melt track widths to achieve a stable process and part density of greater than 99 %. Further, optimized sample states were achieved via thermal post-processing using standard capability aging, super-transus (900 degrees C) and sub-transus (660 degrees C) heat treatment strategies with varying quenching mediums (air, water and ice). The applied heat treatment strategies induce various fractions of a, marten site (alpha', alpha '') in combination with the beta phase and strongly correlated with the observed enhanced mechanical properties and a relatively low elastic modulus. In summary, our work highlights a practical strategy for optimizing the mechanical and corrosion properties of a LPBF produced near beta-type Ti-13Nb-13Zr alloy via careful evaluation of processing and post-processing steps and the interrelation to the corresponding microstructures. Corrosion studies revealed excellent corrosion resistances of the heat treated LPBF samples comparable to wrought Ti-13Nb-13Zr alloys. (C) 2022 The Author(s). Published by Elsevier Ltd.

Automated summary

This study investigates the additive manufacturing of near beta-type Ti-13Nb-13Zr alloys using the LPBF process and explores the optimization of process parameters and post-processing strategies. The research achieves stable process and high part density, and demonstrates excellent mechanical and corrosion properties. The findings are of great significance for the development of personalized orthopedic implants.