Excellent mechanical and corrosion properties of austenitic stainless steel with a unique crystallographic lamellar microstructure via selective laser melting

Crystallographic Orientation Control of 316L Austenitic Stainless Steel via Selective Laser Melting

“…3,4) The formation of CLM was achieved by appropriate modification of the laser condition based on the single-crystalline formation. 13) However, the single crystalline-like texture with {001} orientation in the build direction is reported for the first time under the X-scan strategy in SLM.…”

“…The melt pool with a smaller depth/ width ratio, generated in Specimen_B, indicates conduction mode melting. It has been argued that the shape of the melt pool controls the crystallographic texture formation 13,20) because the melt pool shape reflects the temperature distribution; thus, affects the directions of the thermal gradient and solid/liquid interface migration. In the conduction mode, the curvature of the melt pool bottom decreases during solidification, and the migration of the solid/liquid interface is frequently toward the build direction as solidification proceeds.…”

“…When the vertically grown columnar cells are formed, the orientation is easily inherited through epitaxial growth. 13) Regarding the formation of the single-crystalline like texture with {001} orientation in the build direction (Specimen_A), the melt pool sidewall that towers almost vertically and the relatively small curvature of the melt pool bottom are considered to be involved in the mechanism. Lateral migration of the solid/liquid interface at the melt pool sidewall and upward migration of the solid/liquid interface at the bottom take place and struggle with each other in the lower half of the deep keyhole-type melt pool, leading to bidirectional cell growth in the y-and z-directions.…”

Corrosion behaviour of 316L stainless steel manufactured by selective laser melting

“…MnS inclusions are typically not found in SLM 316L stainless steel . The formation of an intragranular cellular structure in combination with randomly distributed nanoinclusions improves the mechanical properties of SLM 316L stainless steel …”

“…Although there is already a significant body of literature on this topic, it appears that the effect of the microstructure of additively manufactured stainless steel on corrosion behaviour is not completely understood yet. As an example, it is commonly reported that selective laser melted 316L stainless steel displays a higher corrosion resistance than a traditional wrought material with comparable chemical composition . Nevertheless, it is also reported in some cases that as produced SLM stainless steel exhibits lower corrosion resistance than the wrought counterpart due to its complex microstructure or to the presence of defects related to the SLM process .…”