Enhanced tribological performance of laser directed energy deposited Ti5Si3/Ti3Al composite coatings through ultra-fine network structure

Laser directed energy deposition (LDED) is an emerging manufacturing method that could tune the microstructure of metal alloys such as network structures. In this work, in order to develop high-performance composite coatings to enhance the service durability of critical components under extreme wear conditions, a network structure is realized in Ti 5 Si 3 /Ti 3 Al composite coating via tailoring the volume ratio of Ti6Al4V to AlSi10Mg by LDED. At 60 % Ti6Al4V/40 % AlSi10Mg, the first precipitated Ti 5 Si 3 moved to the grain boundary of Ti 3 Al matrix during the solidification process, that leads to the formation of network structure. Compared with the other two coatings studied, the coating with network structure has the lowest wear rate of 1.27 ± 0.12 × 10 −4 mm 3 /Nm, which is much lower than that (4.30 ± 0.32 × 10 −4 mm 3 /Nm) of the as-deposited Ti6Al4V. This reduction is primarily attributed to the transformation of wear mechanisms, as a result of the increased microhardness coupled with the reduced sensitivity to adhesive wear through the Ti 5 Si 3 specific network structures. Our findings provide a straightforward approach to producing excellent wear resistance composite coating.