Chemical and mechanical post-processing of Alloy 718 built via electron beam-powder bed fusion: Surface texture and corrosion behavior

Alloy 718 specimens manufactured via electron beam-powder bed fusion (EB-PBF) were subjected to post-processing techniques, such as thermal post-treatment and surface finishing. Hot isostatic pressing followed by solution-aging heat treatment (HIP-HT) was used as the thermal post-treatment. Surface finishing techniques, such as turning (TU), shot peening (SP), chemically accelerated vibratory finishing (CAVF), and electro-polishing (EP), were applied on the as-built and HIP-HT specimens. The surface texture of all the specimens was characterized, with the HIP-HT specimen having the highest area arithmetical mean height (Sa) value of 52 +/- 1.8 mu m and the TU specimen having the lowest at 1.1 +/- 0.1 mu m. The corrosion performance, typically associated with surface texture, was not always tied to the overused Sa value. CAVF had the highest polarization resistance of 75.8 k Omega cm(2) among the studied methods, followed by TU with polarization resistance of 43.8 k Omega cm(2) , showing that the two techniques have a great potential for improving the surface characteristics of the EB-PBF-built Alloy 718 parts. (C) 2022 The Authors. Published by Elsevier Ltd.