Influence of selective laser melting process parameters on the microstructure, corrosion resistance, and mechanical properties of 2205 duplex stainless steel

This study successfully fabricated 2205 duplex stainless steel (DSS) under varying volumetric energy densities using SLM and accurately simulated the melt pool solidification process during SLM via Ansys-APDL. The study elucidated the relationship between in-situ annealing time and the austenite formation mechanism during the melt pool solidification of DSS. It was found that at a constant volumetric energy density, the in-situ annealing time remains similar, whereas increasing the energy density leads to a prolonged annealing time, which is positively correlated with the austenite content in the duplex steel. SEM, EBSD, and TEM observations revealed that austenite predominantly forms at the phase boundaries between adjacent ferrite grains. Additionally, X-ray photoelectron spectroscopy (XPS) was used to analyze the composition of the passive film formed on DSS during Cl - corrosion resistance. The corrosion resistance of DSS is synergistically governed by the formation of a dual-layer passive film and the galvanic coupling between austenite and ferrite phases. The duplex passive film comprises an outer Fe 2 O 3 layer and an inner Cr 2 O 3 layer. The strengthening mechanisms in DSS include grain refinement strengthening, solid solution strengthening, and dislocation strengthening. The complex interplay among these mechanisms collectively determines the overall strength of DSS.