Oxidation assisted intergranular cracking in 718 Nickel Superalloy: on the mechanism of dynamic embrittlement

Varela, Amanda de Vasconcelos; Deus, Henrique Dias de; Siqueira, Maisa Conceição de; Rezende, Mônica Costa; Almeida, Luiz Henrique de

doi:10.1016/j.jmrt.2018.02.008

Cited by 19 publications

(5 citation statements)

References 12 publications

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“…The embrittling behaviour is reported between 500 and 900°C, with maximum of embrittlement around 600°C [148]. The intergranular cracking of Ni-based superalloys, caused by the diffusion of atomic oxygen at the grain boundaries (GB), is known as Oxidation Assisted Intergranular Cracking (OAIC) [149] or dynamic embrittlement [150]. A similar process of time-dependent decohesion at GB may occur under sustained or cyclic loading, determined by interactions with oxygen at the crack tip for Ni-based superalloys [151].…”

Section: Dynamic Embrittlementmentioning

confidence: 99%

“…Embrittling elements may be present in the alloy or oxygen from surrounding atmosphere may diffuse into the steel lattice and induce cracking along GB in the alloy. Ni-based superalloy IN718 was designed for high temperature, but its application is limited to 650°C due to the embrittlement occurring at higher temperatures [149]. For the Ni-based superalloy U720Li no embrittlement was reported below 600°C, with trans-granular failure observed.…”

Section: Additive Manufacturingmentioning

confidence: 99%

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Materials challenges in hydrogen-fuelled gas turbines

Stefan

Talic

Larring

et al. 2021

International Materials Reviews

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With the increased pressure to decarbonize the power generation sector several gas turbine manufacturers are working towards increasing the hydrogen-firing capabilities of their engines towards 100%. In this review, we discuss the potential materials challenges of gas turbines fuelled with hydrogen, provide an updated overview of the most promising alloys and coatings for this application, and highlight topics requiring further research and development. Particular focus is given to the high-temperature oxidation of gas turbine materials exposed to hydrogen and steam at elevated temperatures and to the corrosion challenges of parts fabricated by additive manufacturing. Other degradation mechanisms such as hot corrosion, the dual atmosphere effect and hydrogen diffusion in the base alloys are also discussed.

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Section: Dynamic Embrittlementmentioning

confidence: 99%

Section: Additive Manufacturingmentioning

confidence: 99%

Materials challenges in hydrogen-fuelled gas turbines

Stefan

Talic

Larring

et al. 2021

International Materials Reviews

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“…Therefore, it is crucial to understand how the g matrix behaves inelastically. Dynamic strain ageing (DSA), which is also known as the Portevin-Le Chatelier (PLC) effect (Marais et al, 2012), in IN718 usually manifests itself at high temperatures in the form of a negative strain rate sensitivity (NSRS), serrated yielding and propagating localised strain rate bands (Zhang et al, 2005;Nalawade et al, 2008;Chen and Chaturvedi, 1997;Fournier et al, 2001;Garat et al, 2008;Prasad et al, 2010Prasad et al, , 2013Max et al, 2014;Hale et al, 2001;Maj et al, 2014;Rezende et al, 2015;Li et al, 2015;Varela et al, 2018). For ageing treated IN718, it is found that DSA can occur within certain temperature (from 200 8 C to 700 8 C) and strain rate (e.g.…”

Section: Investigationsmentioning

confidence: 99%

Experimental and numerical investigations of dynamic strain ageing behaviour in solid solution treated Inconel 718 superalloy

Song

Qin

et al. 2020

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Purpose The purpose of this paper is to systematically investigate the dynamic strain aging (DSA) effect in solid solution treated IN718 at different temperatures through experiments and simulations to gain an understanding of the inelastic deformation mechanisms. Design/methodology/approach In the present work, uniaxial tensile tests have been carried out in conjunction with finite element (FE) simulations to investigate the behaviour of the solid solution treated Inconel 718 superalloy at different temperatures and strain rates. Dynamic strain aging (DSA) effects, which manifested during the tests in the form of a negative strain rate sensitivity and stress serrations, are investigated. The most significant DSA effect occurs at 500°C and at a strain rate of 10–4 s-1. In a newly proposed rate-dependent constitutive formulation, the DSA model, proposed by McCormick, Kubin and Estrin, was introduced into slip-assisted solute hardening, and an activation energy-dependent exponential flow rule was adopted. Findings The observed negative strain rate sensitivity and stress serrations are well predicted by a 3 D FE. The FE results indicate that the equivalent plastic strain rate distribution in the specimen gauge length is as highly inhomogeneous as in the other materials exhibiting DSA effects such as aluminium and titanium alloy. During inelastic deformation, propagating high strain rate bands can be closely correlated to the stress serrations. Originality/value For the DSA effect in solid solution treated IN718, the existing researching mainly focuses on the mechanical properties experiment and microstructure observation. In this study, a constitutive formulation, combined with the DSA model, has been proposed, and the mechanical behaviors, including the DSA effect, have been well predicted by a finite element model.

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“…Nickel and nickel-based superalloys are widely used in space, aviation, chemical and petrochemical industries owing to their relatively high strength at high temperatures [1][2][3]. But their hot corrosion resistance needs to be improved through various surface treatments [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and hot corrosion behavior of hot dip siliconized coating on Ni-base superalloy IN738LC

Targhi

Omidvar

Hadavi

et al. 2020

Mater. Res. Express

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Nickel-based superalloys are widely used at elevated temperature applications because of their high corrosion and oxidation resistance characteristics as well as high stability. To improve the hot corrosion resistance of Nickel-based superalloys, different coatings are applied. In this study, nickelbase superalloy Inconel 738LC was coated via a novel hot-dip diffusion siliconizing process and the corrosion behavior was investigated by XRD, SEM and EDS analyses. A sever degradation and poor hot corrosion resistance was detected by the uncoated sample, while the siliconized coated sample possessed high corrosion resistance. It was figured out that the high hot corrosion resistance of the coated sample was due to the formation of SiO 2 protective scale in the surface layer which protects the substrate elements in the hot corrosion environment.

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Oxidation assisted intergranular cracking in 718 Nickel Superalloy: on the mechanism of dynamic embrittlement

Cited by 19 publications

References 12 publications

Materials challenges in hydrogen-fuelled gas turbines

Materials challenges in hydrogen-fuelled gas turbines

Experimental and numerical investigations of dynamic strain ageing behaviour in solid solution treated Inconel 718 superalloy

Microstructure and hot corrosion behavior of hot dip siliconized coating on Ni-base superalloy IN738LC

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