Additive manufacturing of alumina-silica reinforced Ti6Al4V for articulating surfaces of load-bearing implants

In this study, functional gradation via layer-wise additive manufacturing was coupled with Al2O3 and SiO2 ceramics' advantages to creating a composite of Ti6Al4V (Ti64) with improved hardness and wear resistance. It was hypothesized that with Al2O3 and SiO2 into Ti64, wear-resistance and hardness would increase compared to the base Ti64 alloy. It was also hypothesized that if the structure could be created, an additional laser pass (LP) over the structure's top surface would further increase the hardness. Successfully fabricated composite structures were found to have varying phases of TiSi2 and Ti5Si3 . Refined a-Ti grains were present in the composite region. The interface between the composite and pure Ti64 regions was crack-free, indicating a metallurgically sound bond. Dendritic microstructures were observed with the addition of LP on the composite top surface. Hardness was increased from 323.8 +/- 9.6 HV in Ti64 substrate to 434.7 +/- 7.3 HV, and 677.1 +/- 29.7 HV in 3D Printed Ti64 and the composite sample, respectively. An LP increased hardness further to 938.8 +/- 57.5 HV, a 186% increase in hardness than the original Ti64 alloy. Wear resistance was also increased with the addition of Al2O3 and SiO2 by similar to 90%, indicating the potential processing variations placed on this material system to produce structures with site-specific functionality for biomedical applications, particularly in articulating surfaces of load-bearing implants.