Abstract
<title>Abstract</title> <p>To optimize the performance of Ti6Al4V coatings fabricated by laser directed energy deposition (LDED), ultrasonic impact treatment (UIT) was adopted for surface strengthening. In this study, the effects of ultrasonic impact power on the surface roughness, phase composition, microstructure, wear resistance, and corrosion resistance of the Ti6Al4V coating were investigated. The results show that UIT process does not change the phase composition of the Ti6Al4V cladding layer but effectively improves the surface quality by reducing surface waviness and burrs. The UIT process can refines the grains, and the grain refinement becomes more pronounced with increasing UIT power. Regarding performance enhancement, compared with the untreated Ti6Al4V cladding layer, UIT significantly improves the wear resistance. The friction coefficient and wear rate of the 1000 W UIT-treated layer are remarkably reduced, which is primarily attributed to grain boundary strengthening from grain refinement and the dense plastic deformation strengthening layer formed on the surface. Furthermore, the corrosion resistance of cladding layer is synchronously improved, with its corrosion potential (Ecorr) increasing from − 0.663 V vs. SCE of the untreated sample to -0.530 V vs. SCE of 1000 W UIT-treated sample.</p>