Ming Wen

Improvement of the biomedical properties of titanium using SMAT and thermal oxidation

Titanium and its alloys are excellent candidates for biomedical implant. However, they exhibit relatively poor tribological properties. In this study, a two-step treatment including surface mechanical attrition treatment (SMAT) combined with thermal oxidation process has been developed to improve the tribological properties and biocompatibility of Ti. Ti after two-step treatment shows excellent wear-resistance and biocompatibility among all Ti samples, which can be ascribed to the highest surface energy, well crystallinity of rutile layer on its surface. Overall, the two-step treatment is a prospective method to produce excellent biomedical Ti materials.

Wear Behaviour of Pure Ti with a Nanocrystalline Surface Layer

A nanocrystalline (NC) layer with the thickness of 30 µm was produced on pure titanium surface by surface mechanical attrition treatment (SMAT). Microstructure observation indicated that the grain size increases with depth from the treated surface. The friction coefficient decreases and the wear resistance increases with the SMAT sample as compared to its coarse-grained counterpart. The improvement of the wear properties could be attributed to the higher hardness of SMAT sample.

Mechanical Property and Microstructure of Ti-Ta-Ag Alloy for Biomedical Applications

Ti and some of its alloys (e.g. Ti–6Al–4V alloy) have become the metals of choice for the endosseous parts of presently available dental implants. In the present study, Ti-Ta-Ag alloys with a different Ag content were prepared using vacuum sintering (VS) and spark plasma sintering (SPS) process. The microstructure and mechanical properties of the Ti-Ta-Ag alloys were investigated. The results show that dense Ti-Ta-Ag alloys prepared using the SPS process exhibit high hardness and a suitable elastic modulus for implant materials for load-bearing applications. The effect of preparation methods on the microstructure of Ti-Ta-Ag alloys is discussed.

Morphology evolution during annealing and electrical conductivity of titania nanotube films

Titania nanotube films were produced by anodization of titanium foil. The titania nanotube films were annealed at different temperatures. Morphology evolution, phase transformation and electrical conductivity of the titania nanotubes were studied. Results showed that the nanotube walls became rough, porous and even collapsed after annealed at 400, 500 and 600 °C respectively. Titania anatase phase formed after annealed at 400 °C; the amount of anatase phase increased as the annealing temperature increased. The conductivity of the nanotube film annealed at 400 °C was improved greatly compared with the conductivity of the as-anodized nanotube film. However, the conductivity of the nanotube films annealed at higher temperatures decreased. The effect of the morphology on the electronic conductivity of the titania nanotube films was discussed.