Experimental investigation of laser remelting in directed energy deposition (DED) of CPM-9V

Abstract

Laser-directed energy deposition (L-DED) is a versatile additive manufacturing process with a wide range of applications due to its ability to create complex geometries and heterogeneous structures. However, internal porosity and surface defects can hamper the part quality produced by the L-DED process, especially at high deposition rates. While hot-isostatic pressing (HIP) is commonly used as a post-processing technique to minimize internal porosity, it is inadequate for pores near the surface. Recently, laser remelting has been explored as an alternative to improve the quality of DED-produced parts. This research aims to assess the performance of the in situ laser remelting process in terms of decreased porosity, increased micro–hardness, and improved surface finish of the L-DED parts. The experimental findings reveal that laser remelting reduces the porosity in the as-deposited sample by 72% on average while improving the micro–hardness by 13%. A significant improvement of 68% is also observed in the surface finish of the remelted sample.