Density Determination and Metallographic Surface Preparation of Electron Beam Melted Ti6Al4V.

摘要

Electron Beam Melting (EBM) is currently used to produce customized Ti6Al4V cranial implants for wounded warfighters who require cranial reconstruction surgeries due to loss of skull tissue. Infections occurring at implant sites may be due to the surface topography of the implants, which favor bacterial contact and adhesion. The objective of this study was to establish density determination and metallographic surface preparation procedures for EBM Ti6Al4V coupons. Densities of EBM Ti6Al4V coupons were measured using the Archimedes method and compared to those of commercial medical grade (CMG) Ti6Al4V coupons. Surfaces of EBM Ti6Al4V and CMG Ti6Al4V coupons were polished to 60 grit silicon carbide (SiC), 120 grit SiC, 400 grit SiC, and colloidal silica finishes and analyzed using scanning electron microscopy (SEM). Statistical analysis to compare density measurements of EBM and of CMG Ti6Al4V was performed using a t-test. The average density of EBM Ti6Al4V and CMG Ti6Al4V were 4.26 plus or equal to 0.04 g/cm3and 4.41 plus or equal to 0.01 g/cm3, respectively. The difference in densities between EBM Ti6Al4V and CMG Ti6Al4V were statistically significant (p < 0.05). SEM analysis of polished EBM Ti6Al4V samples showed a progressive change in surface topography from polishing with 60 grit SiC paper to polishing with colloidal silica suspension. The density of CMG Ti6Al4V was close to the theoretical density (4.43 g/cm3). One factor contributing to an average lower density of EBM Ti6Al4V compared to CMG Ti6Al4V may be due to the presence of porosity, which is known to be introduced during the EBM process. Conventional metallographic surface preparation can be used to engineer the surface of EBM Ti6Al4V to produce different surface topographies.