Pulsed Laser Additive Manufacturing for 316L Stainless Steel: A New Approach to Control Subgrain Cellular Structure

An in-depth examination of the effects of a pulsed laser on the additively manufactured 316L stainless steel by laser powder bed fusion (L-PBF) was conducted in this work. It demonstrated that dense parts can be obtained over a broad spectrum of parameters during pulsed laser L-PBF. The results show that a pulsed laser can significantly refine the sub-micron cellular structure and microsize grain structure and hence enhance the mechanical properties of L-PBF 316L SS. Simulations conducted via FLOW-3D validate the distinctions in thermal history between various printing parameters. The improved cooling rate during the laser process led to microstructure refinement. The Hall–Petch relationship of the AM 316L SS at the sub-micron scale was determined and could provide a guideline for Hall–Petch strengthening of AM stainless steel with cellular structure refinement.