On the effects of build orientation, strain rate sensitivity and sample thickness on the mechanical behavior of 316l Stainless Steel manufactured by Selective Laser Melting

Carassus, Hugo; Morvan, Hervé; Haugou, Grégory; Guérin, Jean-Dominique; Sadat, Tarik; Guérard, Sandra; Markiewicz, Éric

doi:10.1051/epjconf/202125005009

Cited by 1 publication

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References 11 publications

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“…The specimen geometry was a type B 4 × 20 according to DIN 50125:2021-08 [35], and was obtained by machining of cylinders with a 2 mm allowance in the conditions SA + Q and HIP + SA + Q. The load was applied vertically and parallel to the building axis, i.e., in the "weakest" direction [36]. Four specimens were tested for each heat treatment condition and process gas, and the overall mechanical properties were determined as an average of all specimens per group.…”

Section: Tensile and Hardness Testingmentioning

confidence: 99%

Influence of the L-PBF Process Atmosphere on the Microstructure and Tensile Properties of AISI 318LN Duplex Stainless Steel

Mirz

Herzog

Broeckmann

et al. 2022

JMMP

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Duplex stainless steels (DSSs) have excellent mechanical properties, owing to their austenitic–ferritic microstructure. The phase equilibrium strongly depends on solidification conditions and chemical composition, where elemental nitrogen significantly stabilizes the austenitic phase. When DSSs are processed by laser powder bed fusion (L-PBF) under an argon atmosphere, the rapid cooling rates result in an undesirable fully ferritic microstructure. To better understand the microstructure formation, this study examined the influence of the L-PBF process atmosphere on the porosity, microstructure, and mechanical properties of DSS AISI 318LN. Gaseous argon and nitrogen were used as a protective atmosphere, and specimens were analyzed in the as-built and post-processed conditions via optical and electron microscopy, electron backscatter diffraction, and tensile testing. Specimens processed under a nitrogen atmosphere showed a lower initial density in the as-built conditions, and tended to form more lack-of-fusion and gas pores compared to specimens processed under argon. The different defect types in nitrogen-processed specimens were still present after solution-annealing and quenching, leading to a 13% lower tensile strength and 43% lower elongation at fracture. Differences in phase equilibrium caused by the process atmosphere could not be established. All differences in porosity can be minimized by hot isostatic pressing, thus resulting in comparable mechanical properties of argon- and nitrogen-processed specimens.

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Section: Tensile and Hardness Testingmentioning

confidence: 99%