Unveiling the role of heat treatment approaches in Tailoring corrosion performance of Laser Powder − Directed Energy Deposited SS304

This study investigates the effect of different post-processing heat treatment approaches on the corrosion behavior of Laser Powder-Directed Energy Deposited (LP-DED) SS304. Samples were fabricated using optimized LP-DED parameters: laser power of 400 W, scan speed of 800 mm/min, feed rate of 4 g/min, 0.6 mm beam diameter, and 33 % track overlap.Electrochemical analysis revealed significant differences in corrosion performance depending on the applied heat treatment approach. This treatment resulted in changes to residual stress, microstructure, and oxide layer characteristics which together influence the corrosion rate (CR). The stress-relief annealed (SRA) samples significantly improved corrosion resistance by up to 90 % compared to the as-built condition, while preserving the fine microstructure formed during the LP-DED process and maintaining a stable protective oxide layer. Solution treated and different quenched samples exhibited varying CR depending on the cooling rate and resulting coarse grain structure. These findings highlight the significant influence of post-processing heat treatments on corrosion behavior and microstructural characteristics.