Formation of two distinct cellular structures in 316L stainless steel fabricated by micro-laser beam powder-bed-fusion

Abstract

Micro-laser beam powder-bed-fusion (µL-PBF) technique offers the capability to fabricate metallic components with enhanced surface quality and geometrical accuracy through refinement of processing parameters. Here, we elucidate the interrelated nature governing the scale-down of processing parameters and the evolution of solidification microstructures in a µL-PBF fabricated 316L stainless steel. We reveal the formation of two distinct cellular structures displaying different chemical segregations and dislocation arrangements within molten pools. Our findings underline the importance of chemical heterogeneity in modulating the evolution of dislocation structures, a phenomenon attributed to the intrinsic thermal gradients and unique thermal histories associated with the µL-PBF technique.