Alloys-by-design: A low-modulus titanium alloy for additively manufacture d biome dical implants

The performance of many metal biomedical implants - such as fusion cages for spines - is inherently limited by the mismatch of mechanical properties between the metal and the biological bone tissue it promotes. Here, an alloy design approach is used to isolate titanium alloy compositions for biocompatibility which exhibit a modulus of elasticity lower than the Ti-6Al-4V grade commonly employed for this application. Due to the interest in alloys for personalised medicine, additive manufacturability is also considered: compositions with low cracking susceptibility and with propensity for non-planar growth are identified. An optimal alloy composition is selected for selective laser melting, and its processability and mechanical properties tested. Additive manufacturing is used to engineer an heterogeneous microstructure with outstanding combined strength and ductility. Our results confirm the suitability of novel titanium alloys for lowering the stiffness towards that needed whilst being additively manufacturable and strong. (c) 2022 The Authors. Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Automated summary

This study utilizes an alloy design approach to identify biocompatible titanium alloy compositions with a lower modulus of elasticity than the commonly used Ti-6Al-4V grade. The study also considers the additive manufacturability of the alloys and identifies compositions with low cracking susceptibility and propensity for non-planar growth. An optimal alloy composition is selected for selective laser melting, resulting in an engineered microstructure with outstanding combined strength and ductility.