Effect of volumetric energy density on micro-structural evolution, wear, and corrosion properties of SLM 316L stainless steel

The micro-structural evolution, wear, and corrosion behaviour of select laser melting 316L stainless steel at different volumetric energy density (VED) conditions was investigated. The amount of un-melted defect was decreased as VED was increased. The austenite grains changed from equiaxed to columnar at surface, and the melting pool exhibited a fish-scale morphology at cross-section with an increase in VED. The fraction of low-angle boundary grain and dislocation density was increased with an increase in VED. The sample's hardness and wear rate were the lowest at 57 J·mm −3 . With an increase in VED, the sample's hardness and wear resistance were gradually enhanced. The sample's corrosion resistance was poor at 57 J·mm −3 due to un-melted defects, optimal at 62 J·mm −3 and decreased with the increase in VED owing to grain coarsening. At 125 J·mm −3 , the high LAGB and dislocation density enhanced sample's corrosion resistance. The wear and corrosion mechanism were discussed in detail.