Curriculum Vitae

New concepts for biomedical applications with metal matrix composites

Ana Maria Pires Pinto

Universidade do Minho, Portugal

Abstract
Currently, there is a significant need to improve biomedical implant device performance because of the growing elderly population. Metallic alloys (Ti alloys and CoCrMo) remain the most adequate materials for orthopedic and dental implants. However, some major clinical concerns are still valid, namely bone resorption due to stress shielding, low tribocorrosion resistance and lack of bioactivity. The first issue is related with biomechanical mismatch of Young's modulus between bone and metallic implant (determined by the bulk properties) while the other two are linked to the implant surface properties. Hard ceramic or bioactive coatings are being widely used in order to address these issues, however, failure at the metal-coating interface is a matter of major concern due to the changes in phase composition at high processing temperatures and the coefficient of thermal expansion (CTE) mismatch between the implant material and the coating. On the other hand, it is possible to produce hybrid MMCs with a gradual increase on the volume fraction of the ex-situ and in-situ reinforcing phases from core to the surface, as a functionally graded material (FGM), allowing to obtain a tough core of a biomedical alloy and a hard/tribocorrosion-resistant/bioactive/porous surface in the same time. The aim of this talk is to introduce some possibilities on developing functionalized implant materials by using functionally graded hybrid structures. Since a major concern is to control the surface and sub-surface properties in order to improve the tribocorrosion performance of the system, a special attention will be given on the tribocorrosion behaviour of the composite structures.