Design of a low Young's modulus Ti-Zr-Nb-Sn biocompatible alloy by in situ laser powder bed fusion additive manufacturing process

A new metastable beta Ti-22Zr-11 Nb-2Sn (at%) biomedical titanium alloy was elaborated from elemental powders by in situ laser powder bed fusion technique (L-PBF). Iterative design of experiments was used to identify optimized manufacturing parameters to obtain dense and homogeneous parts (>99.3%) with low unmolten niobium fraction (<0.05%). The microstructural and mechanical properties of this alloy were investigated in its as-fabricated state and after two heat-treatments at 400 C and 700 C, respectively. The alloy, showing a beta-type microstructure, possesses a very low Young's modulus (-50 GPa) combined with a high tensile strength reaching about 1100 MPa after heat-treatment. These properties are very suitable for medical devices in osseous site such as hip prostheses or dental implants and the results were compared to the Ti-6Al-4 V ELI (wt%) medical grade fabricated from pre-alloyed powders. Thus, the present work demonstrates the significant potential of the in situ L-PBF technique to elaborate highly biocompatible titanium alloys with tailored chemical compositions.

Automated summary

A new beta Ti-22Zr-11Nb-2Sn biomedical titanium alloy was fabricated using in situ laser powder bed fusion technique. Optimized manufacturing parameters were determined through iterative design of experiments to achieve dense and homogeneous parts with low unmolten niobium fraction. The alloy exhibited a beta-type microstructure with a low Young's modulus and high tensile strength, making it suitable for medical devices in osseous site.