Two-Step Laser Based Surface Treatments Of Laser Metal Deposition Manufactured Ti6al4v Components

Surface treatment is required in additive manufacturing (AM) to improve the surface quality. However, laser polishing (LP) with a small molten zone cannot directly remove the surface waviness generated by laser metal deposition (LMD). In this study, a two-step surface treatment involving picosecond laser machining (PLM) and LP is presented to improve the surface quality of Ti6Al4V components fabricated by LMD. The effectiveness of PLM on the surface waviness removal is investigated by evaluating 3D surface topography and 2D surface profile under different processing parameters. The surface roughness improvement is mainly contributed by LP as compared to PLM. The surface quality can be greatly improved by the present two-step laser based treatment. The microstructure evolution in the present treatment is also investigated through experimental observation and thermal analysis based on finite element method.