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Poster communications

Microstructure impact on high temperature corrosion behavior of AISI 316L stainless steel additively manufactured by Selective Laser Melting (AM-SLM)

Abstract : Additive Manufacturing by Selective Laser Melting (AM-SLM) is a near-net shape method producing dense and geometrically complex materials from micrometric powders. This process involves complete melting and very high cooling rates who induce a refinement of microstructure, improving the mechanical properties of the material [1,2]. However, the impact of these new microstructures on real functioning properties, like for instance the high temperature durability, needs to be studied. In this purpose, AISI 316L is considered in this work. Samples elaborated by AM-SLM and by conventional metallurgy were oxidized under laboratory air at 900°C for periods up to 3000h. The results highlight better behaviour for AM samples, which present a very good corrosion resistance throughout the 3000 hours. The conventional samples show a good resistance only during the first 1000 hours. These differences were related to the different composition of the oxide layers growing on the surface of the samples during the high temperature ageing: protective chromia for AM-SLM and non-protective iron oxides for conventional samples. To explain these differences of reactivity, several hypotheses were considered. XRD, SEM-EBSD and TEM studies were performed on initial samples in order to evaluate their microstructure, surface mechanical state and crystallographic orientation. The most promising hypothesis seems to be related to the microstructure (probably at nanoscale) of the samples. For AM-SLM coupons, a typical cellular structure was identified by TEM, with a size between 0.2 and 1 µm, corresponding to a very dense network of dislocations, which accumulate forming cell walls. Dislocation might act during the high temperature exposure as short-circuit paths for Cr diffusion from the bulk to the surface allowing the growth of protective scales for long ageing times. Moreover, AM-SLM samples found to contain large quantity of nano-inclusion that might equally influence corrosion behaviour.
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Poster communications
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https://hal.archives-ouvertes.fr/hal-03169227
Contributor : Corentin Siri <>
Submitted on : Monday, March 15, 2021 - 11:01:11 AM
Last modification on : Friday, March 19, 2021 - 3:20:48 AM

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  • HAL Id : hal-03169227, version 1

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Corentin Siri, Ioana Popa, Rémi Chassagnon, Cécile Langlade, Alexis Vion, et al.. Microstructure impact on high temperature corrosion behavior of AISI 316L stainless steel additively manufactured by Selective Laser Melting (AM-SLM). C'NANO, Dec 2019, Dijon, France. 2019. ⟨hal-03169227⟩

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