Anisotropic cellular structure and texture microstructure of 316L stainless steel fabricated by selective laser melting via rotation scanning strategy

In this work, the effects of solidification and remelting under chessboard 67 degrees rotation scanning strategy on the microstructure and properties of selective laser melted (SLMed) 316L stainless steel (316L SS) were studied, including dendrite microstructure, element distribution, grain orientation, dislocation structure, microhardness and corrosion resistance. We put forward a complete foundation relationship among texture, cellular structure and mechanical property influenced by anisotropy. Main results are summarized as follows: The (101) texture formation is the result of dendrite epitaxial growth. The cel-lular dislocation structure highly overlapped with dendrite significantly changed in remelting zone. Hence the high ratio of (101) texture signifies the anisotropy distribution of epitaxially growth dendrite which released the internal stress. The dislocation structure has a contribution to strength similar work hardening strengthening. Meanwhile, the 316L SS obtains Orowan strengthening via the nano oxide pin-ning effect in dislocation wall. Thus, the dislocation density and oxide distance obvious changed in dif-ferent directions of cellular dislocation structure, resulting in the cellular dendrite regions performed higher microhardness than the columnar dendrite regions. The drastic change of dendrite increased the crack sensitivity of SLMed 316L SS, and the junction of different epitaxially growth direction den-drites formed high energy grain boundary. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study investigates the effects of solidification and remelting under a chessboard 67 degrees rotation scanning strategy on the microstructure and properties of selective laser melted 316L stainless steel. The findings provide insights into the relationship between microhardness, dislocation structure, and texture, contributing to a better understanding of the characteristics of 316L stainless steel.