Abstract
Currently, the post-processing of metal/composite products manufactured using 3D printing technologies (direct energy deposition or powder bed fusion methods) has become increasingly important in additive manufacturing chains. The post-processing is the final stage that defines the surface finish and functionality, as well as the physico-mechanical properties of end-products. The application of non-material removal mechanical surface post-treatments (sandblasting (SB) followed by the laser shock peening (LSP) and ultrasonic impact treatment (UIT)) for surface finishing of superalloy 718 fabricated by the laser powder bed fusion (LPBF) 3D printing innovative technology was analyzed in this work. The surface roughness parameters and topography/texture, structure, and microhardness depth profiles in the subsurface layers were studied in the INCONEL 718 parts produced by LPBF and post-processed by SB + LSP and SB + UIT. The transmission electron microscopy of the SB + LSP and SB + UIT-treated samples showed significant grains’ refinement in severely deformed top surface layers which resulted in the increase in the hardness from ~ 3.8 GPa to ~ 5.5 GPa and ~ 5.3 GPa, respectively. A surface microrelief was formed with a noticeably reduced roughness (Sa = ~ 0.14 µm) after SB + UIT.