Corrosion properties of 304L stainless steel made by directed energy deposition additive manufacturing

The impact of microstructure and processing defects of directed energy deposition (DED) 304L stainless steel on its corrosion behavior was investigated. Materials produced by DED with heat inputs of 0.45 and 0.03 kJ/mm were compared to wrought 304L. Lack of fusion pores in the DED material controlled breakdown potential (Eb) to the first order, reducing it by up to 400 mV versus the base material in 0.6 M NaCl. The hierarchal control of these and other microstructure features, nanoscale oxides and δ-ferrite, and processing features on the Eb of DED 304L is addressed.