Improvement of forming quality, microstructure, and bio-tribological properties of additive manufactured Ti6Al4V with LaB₆ addition

The poor wear resistance limits the applications of Ti6Al4V alloy. The additive manufactured Ti6Al4V alloy, particularly produced in the air, has issues with the poor forming quality. In this study, a rare earth compound (LaB₆) was introduced to enhance both the forming quality and bio-tribological properties of Ti6Al4V alloy. The results show that adding an appropriate amount of LaB₆ can reduce defects (pores). The microstructure is obviously refined due to pinning and heterogeneous nucleation effects, and the La₂O₃ and TiB are formed through the in-situ reactions. The sample with 4 wt% LaB₆ addition exhibits excellent microhardness and bio-tribological properties. Grain refinement, dispersion strengthening and solution strengthening can significantly improve the microhardness, and the bio-tribological properties are further improved when combined with the in-situ network-structured hard TiB whisker (TiBw). This work is expected to provide reference suggestions for the development of additive manufactured titanium alloys and its application in implants.