Effect of heat treatment on the recrystallisation of thin-walled stainless steel 316L fabricated by laser beam powder bed fusion

Additive Manufacturing (AM), particularly laser beam powder bed fusion (LB-PBF), enables fabrication of complex thin-wall geometries, yet post-processing studies on such structures are limited. This work investigates heat-treatment annealing of thin-walled stainless steel 316L (SS316L) built via LB-...

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Bibliographic Details
Main Authors: Charlie Bevan, Nicholas Barnard, Thomas Jones, Robert Lancaster
Format: Article
Language:English
Published: Elsevier 2025-10-01
Series:Materials & Design
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Online Access:http://www.sciencedirect.com/science/article/pii/S0264127525010123
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Summary:Additive Manufacturing (AM), particularly laser beam powder bed fusion (LB-PBF), enables fabrication of complex thin-wall geometries, yet post-processing studies on such structures are limited. This work investigates heat-treatment annealing of thin-walled stainless steel 316L (SS316L) built via LB-PBF. A novel build geometry with wall thicknesses from 0.2–1.8 mm was used to examine microstructures before and after heat-treatment (HT) at 1050 °C and 1150 °C. In the as-built state, thinner walls showed grains oriented in <001> toward the wall centre, while thicker walls exhibited a <101> orientation due to a central band of preferential grain growth, typical of larger LB-PBF SS316L parts. Annealing at 1150 °C produced partial recrystallisation in all samples, reaching 86 % in the thickest walls, whereas 1050 °C annealing had little effect. Analysis of geometrically necessary dislocation density, low-angle boundaries (LAB), and high-angle boundaries (HAB) showed no correlation with recrystallisation behaviour. The primary factor limiting recrystallisation was Mn- and Si-based oxide distributions, which impeded grain boundary migration. This caused a stop-and-go growth mechanism, leading to abnormal grain growth in some cases. Findings highlight that chemical segregation, rather than dislocation structure, controls recrystallisation in thin-walled LB-PBF SS316L.
ISSN:0264-1275