Microstructure evolution and corrosion behaviour of an ASTM A213 T91 tube after long term creep exposure

Fetni, Seifallah; Toumi, Arwa; Mkaouar, Imed; Boubahri, Chokri; Briki, Jalel

doi:10.1016/j.engfailanal.2017.03.023

Cited by 18 publications

(4 citation statements)

References 27 publications

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“…Iron−chromium (Fe-Cr) alloys are prime candidates with outstanding creep strength and heat resistance, for example, T91. 1,2 We may refer to superheaters in boilers, main steam pipelines, and heating furnace piping in the petrochemical industry as some of their current applications. 3,4 Fe-Cr alloys are also one of the prime candidate materials for nuclear fuel cladding, 5,6 specifically for Generation IV nuclear reactors with a life of 60+ years and operating in temperatures as high as 1000 K and extreme radiation doses because they have higher oxidation resistance compared to zirconium alloys.…”

Section: Introductionmentioning

confidence: 99%

“…There is an increasing need for materials that can operate under extreme conditions, specifically elevated temperatures. Iron–chromium (Fe-Cr) alloys are prime candidates with outstanding creep strength and heat resistance, for example, T91. , We may refer to superheaters in boilers, main steam pipelines, and heating furnace piping in the petrochemical industry as some of their current applications. , Fe-Cr alloys are also one of the prime candidate materials for nuclear fuel cladding, , specifically for Generation IV nuclear reactors with a life of 60+ years and operating in temperatures as high as 1000 K and extreme radiation doses because they have higher oxidation resistance compared to zirconium alloys. These emerging needs further emphasize the necessity of computational studies for Fe-Cr alloys, as experimental radiation tests are costly and require a minimum of 7 years of testing.…”

Section: Introductionmentioning

confidence: 99%

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A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

et al. 2021

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We developed a modified embedded atom method (MEAM) potential for Fe-Cr-Si ternary systems. These alloys have superior corrosion and crack resistance, making them candidate materials for several engineering applications such as accidenttolerant fuel cladding. We used a multiobjective optimization approach to match Fe-Cr-Si's elastic constants, ground-state energies, and structural parameters with ab initio calculations. The potential has been parameterized by fitting to a set of literature values obtained using density functional theory (DFT) or experimental studies. The developed potential was used in molecular dynamics (MD) simulations to extract mechanical and thermal properties. We obtained the calculated elastic constants for Fe-Cr-Si binary interactions using the proposed potential, agreeing with ab initio calculations. Our calculated self-diffusion coefficient values and defect formation energy using this potential are in good agreement with the previous literature. Therefore, the developed potential can investigate the fundamental behaviors on an atomic scale under harsh conditions like elevated temperature and irradiation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

et al. 2021

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“…The formation mechanism of the internal oxide layer is still unclear, and more efforts have been made to reveal the evolution of the internal oxide layer in recent years. To date, the selective grain/lath boundary oxidation is the results of preferential oxygen penetration along the grain/lath boundaries, where the Cr carbides were firstly oxidized to form Cr-rich oxides [24][25][26]28,[31][32][33]. In comparison, there are debates on the formation of the nanometric Cr-rich oxide precipitates in the grain interior.…”

Section: Introductionmentioning

confidence: 99%

Understanding the surface oxide evolution of T91 ferritic-martensitic steel in supercritical water through advanced characterization

2020

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The surface oxide scale formed on T91 steel after exposure to deaerated supercritical water (SCW) at 600 ºC for 100-1500 h are characterized in detail to reveal the oxide evolution over time. A triplex structure with outer, inner and internal oxide layers has been confirmed. The thickness of each oxide layer increases with the exposure time following the power law kinetics. The different oxide phases in each oxide layer are the results of the decreasing partial pressure of oxygen inwards the depth of oxide scale. The inner and internal oxide layers are not uniform in Fe and Cr contents. The internal oxide layer consists of Cr-rich oxide precipitates surrounded by metal matrix in the grain interior, which could be explained by the internal oxidation mechanism. After a further longtime exposure, a continuous thin Cr-rich spinel oxide layer is formed at the internal oxide layer-metal matrix interface, which is the result of transition from internal to external oxidation when the outward diffusion of Cr exceeds the inward diffusion of oxygen. The inner oxide layer consists of Cr-rich spinel oxide precipitates surrounded by Fe-rich spinel oxide. The formation of the inner oxide layer is the result of further oxidation of the internal oxide layer where the metal matrix in the grain interior is oxidized into Fe-rich spinel.

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“…10Cr9Mo1VNbN (F91) steel, as a martensitic, heat-resistant steel, has outstanding high-temperature performance and corrosion resistance, and is massively applied in manufacture of steam boiler, valve body, tube and turbine components [1]. The valve discs and seats mainly made of F91 steels are easily subjected to the severe erosion and wear of solid particles under high temperature and pressure in the service process.…”

Section: Introductionmentioning

confidence: 99%

Microstructure Evolution and Failure Behavior of Stellite 6 Coating on Steel after Long-Time Service

et al. 2019

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The microstructure evolution, elements diffusion and fracture behavior of the Stellite 6 weld overlay, deposited on 10Cr9Mo1VNbN (F91) steel by the tungsten inert gas (TIG) cladding process, were investigated after long-time service. Obvious diffusion of Fe occurred from the steel and fusion zone to the Stellite overlay, resulting in the microstructure evolution and hardness increase in the coating, where hard Co–Fe phases, σ phases (Fe–Cr metallic compounds) and Cr-rich carbides (Cr18.93Fe4.07C6) were formed. Besides, the width of the light zone, combined with the fusion zone and diffusion zone, increased significantly to a maximum value of 2.5 mm. The fracture of the Stellite coating samples mainly occurred in the light zone, which was caused by the formation and growth of circumferential crack and radial crack under high temperature and pressure conditions. Moreover, the micro-hardness values in the light zone increased to the maximum (470–680 HV) due to the formation and growth of brittle Co–Fe phases. The formation of these cracks might be caused by formed brittle phases and changes of micro-hardness during service.

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Microstructure evolution and corrosion behaviour of an ASTM A213 T91 tube after long term creep exposure

Cited by 18 publications

References 27 publications

A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

Understanding the surface oxide evolution of T91 ferritic-martensitic steel in supercritical water through advanced characterization

Microstructure Evolution and Failure Behavior of Stellite 6 Coating on Steel after Long-Time Service

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