Development of elastically graded titanium alloys for biomedical applications

^a PSL Research University, Chimie ParisTech - CNRS, Institut de Recherche de Chimie Paris UMR CNRS 8247, 75005 Paris, France
^b BIOTECH DENTAL, 13300 Salon-de-Provence, France
^c Laboratoire Procédés et Ingénierie en Mécanique et Matériaux, PIMM, ENSAM, UMR 8006, CNRS, CNAM, 75013 Paris, France
^d Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux, LEM3 UMR CNRS 7239, Université de Lorraine, île du Saulcy, 57045 Metz Cedex, France
^e Paris Diderot University, Sorbonne Paris Cité, Faculty of dentistry, 75013 Paris, France
^f Hospital Rothschild, AP-HP, 75012 Paris, France

^* corresponding author: stephanie.delannoy@chimieparistech.psl.eu

Abstract

Recent works have shown that the elastic mismatch observed at the bone / implant interface could be responsible for stress shielding issues causing bone resorption phenomena and potentially implant failures. In the present study, new advanced thermomechanical approaches leading to titanium alloys with graded elastic properties are proposed. The underlying philosophy and the whole methodology is detailed here, from the selection of candidates with large elastic variability to the creation of gradients, involving the identification of microstructure-properties relationships and the use of appropriate thermo-mechanical treatments. Applied on Ti-Nb-Zr alloys, these original routes enabled to get the following graded properties: elastic modulus from 85 to 65GPa over 400μm for TNZ alloy by surface deformation, and from 130 to 75GPa over 100μm for Ti-13-13 by preferential dissolution. These promising results thus validated the previously designed material-strategy-process combinations.