Thermal Mechanical Fatigue Behavior of Advanced Overlay Coatings

Czech, N.; Schmitz, F.; Werner, Stefan

doi:10.1080/10426919508935086

Cited by 29 publications

(7 citation statements)

References 7 publications

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“…Common processes for overlay coating deposition are: vacuum plasma spraying (VPS), atmospheric plasma spraying (APS), high-velocity oxy-fuel (HVOF) spraying, low-pressure plasma spraying (LPPS) and electron beam physical vapor deposition (EB-PVD) [1,3,8,9]. The former two produce coatings with a characteristic splat-on-splat structure.…”

Section: Introductionmentioning

confidence: 99%

Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Yuan

Eriksson

Peng

et al. 2013

Surface and Coatings Technology

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MCrAlY coatings are deposited onto superalloys to provide oxidation and corrosion protection at high temperature by the formation of a thermally grown oxide scale. In this project, the oxidation behaviour of a HVOF CoNiCrAlYSi coating on IN792 was studied for both isothermal oxidation (900, 1000 and 1100 °C) and thermal cycling (100-1100 °C). The microstructural evolution of the CoNiCrAlYSi coatings after oxidation was investigated. It was found that the Al-rich β phase is gradually consumed due to two effects: surface oxidation and coating-substrate interdiffusion. Some voids and oxides along the coating-substrate interface, or inside the coating, were considered to play a role in blocking the diffusion of alloying elements. Based on the microstructural observation, an oxidation-diffusion model, considering both surface oxidation and coating-substrate interdiffusion, was developed by using Matlab and DICTRA software to predict the useful life of MCrAlY coatings.A new concept of diffusion blocking is also introduced into the model to give more accurate description on the microstructural evolution. The results from modeling and the experimentally established composition profiles showed good agreement.

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Section: Introductionmentioning

confidence: 99%

Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Yuan

Eriksson

Peng

et al. 2013

Surface and Coatings Technology

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“…Re additions in NiCrAl alloy [18] or NiCrAlY coating [19] have also been shown to improve the alloy's or coating's cyclic oxidation resistance, mainly by affecting the alloy microstructure and phase compositions, making the alloy more ductile and also less susceptible to internal oxidation attacks. However, it was found that high amounts of Re (10 at.%) or Al (24 at.%) could cause an embrittlement of the bond coat material [22][23][24][25].…”

Section: Introductionmentioning

confidence: 97%

Influence of Aluminum and Rhenium on the Isothermal Oxidation Behavior of CoNiCrAlY Alloys

et al. 2010

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The oxidation behavior of a Co32Ni21Cr8Al0.6Y (wt%) alloy with and without the addition of 3.5 wt% rhenium, 2 wt% aluminum or a combination of the two was investigated at 1000°C. Results showed that increasing the Al content from 8 to 10 wt% led to an increase of the alloy b-phase, but did not affect the oxidation behavior. Re addition induced (Cr,Re,Y)-rich phase to precipitate in the alloy, accelerated the h-to a-alumina transformation, reduced the oxidation rate and enhanced the rate of alloy Al diffusion. Adding both Al and Re further improved the oxidation behavior by promoting the development of the external alumina scale and suppressing the formation of Ni, Co containing spinel. This alloy also showed the largest reduction of oxidation rate and emerged to be the most beneficial. A continuous Cr-Re rich layer was observed at the oxide/alloy interface of the Re, Al containing alloy after longer oxidation times, but this layer is not expected to affect the continued growth of the alumina scale.

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“…The TMF behavior of MCrAlY coatings can be improved by composition modification. For instance, the addition of Re to MCrAlY can increase the TMF lifetime [25,86].…”

Section: Fatiguementioning

confidence: 99%

“…The addition of Si and Hf may provide beneficial effect on hot corrosion resistance, while some heavier elements like Ta in the coating may affect the diffusion activities of alloying elements by reducing their diffusion rates [6]. MCrAlY coatings can be deposited or sprayed by a number of techniques: atmospheric plasma spraying (APS), low-pressure plasma spraying (LPPS), vacuum plasma spraying (VPS), electron-beam physical vapor deposition (EB-PVD), and high-velocity oxy-fuel spraying (HVOF) [23][24][25][26].…”

Section: High-temperature Coatingsmentioning

confidence: 99%

Oxidation and Corrosion of New MCrAlX Coatings : Modelling and Experiments

Yuan¹

2014

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after a high-temperature oxidation (the image height is 191 μm). Back: The profiles of alloying elements in a MCrAlY coating-superalloy system after a high-temperature oxidation (the solid curves are simulation results, and the dots are experimental ones).Printed by: LiU-Tryck, Linköping, Sweden, 2014 ISBN: 978-91-7519-247-5 ISSN 0345-7524 Distributed by: Linköping University Department of Management and Engineering SE-581 83, Linköping, Sweden © 2014 Kang YuanNo part of this publication may be reproduced or transmitted in any form without prior permission of the author.iii Abstract MCrAlY coatings ("M" for Ni and/or Co) are widely used for the protection of superalloy components operated at high temperatures such as in the hot sections of gas turbines. The exposure to high temperature can cause coating degradation due to oxidation or hot corrosion at the coating surface. Microstructures in the coating and the coating life are affected also by the diffusion of alloying elements through the coating-superalloy interface. This PhD project, by applying thermodynamic modelling and experimental tests, investigates the oxidation and hot corrosion behavior of new MCrAlX coatings, in which X, referring to minor elements, is used to highlight the functions of such elements.In order to understand and predict the coating degradation progress during thermal exposure, an oxidation-diffusion model has been established for MCrAlX coating-superalloy systems, which integrates the oxidation of aluminum at coating surface, diffusion of alloying elements, and the diffusion-blocking effect in the materials. The predicted chemical composition profile and microstructure agreed well with experimental results in a CoNiCrAlYSiTa-Inconel 792 system. The model was further applied in several coating-superalloy systems to study the influence of coating composition, superalloy composition and temperature on the evolution of microstructure in the coating and the coating life. The results have demonstrated the potential of the model in designing new durable MCrAlX coatings. In addition to the applications in coating-superalloy systems, the model was also adapted for studying the microstructural development in a superalloy in which internal oxidation and nitridation occurred in an oxidation process.The oxidation behavior of some HVOF MCrAlX coatings was studied by thermal exposure at different temperatures (900, 1000, 1100 °C). Different spinels formed above the alumina scale, depending on the oxidation temperature. The minor alloying elements, Ru and Ir, had no direct influence on the oxidation behavior but may affect the phase stability in the coating.MCrAlX coatings were also tested in 48-hour cycles at 900 °C in different hot corrosion environments containing sulphates and/or SO 2 . The results showed that the coating performance was dependent on coating quality, concentration of Al and Cr in the coating, and the hot corrosion condition. It was also found that the addition of SO 2 in the environment may not necessarily be bad for hot cor...

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Thermal Mechanical Fatigue Behavior of Advanced Overlay Coatings

Cited by 29 publications

References 7 publications

Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Influence of Aluminum and Rhenium on the Isothermal Oxidation Behavior of CoNiCrAlY Alloys

Oxidation and Corrosion of New MCrAlX Coatings : Modelling and Experiments

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