Evolution and its stability of M23(C,N)6 carbonitride in martensite ferritic steel during long-term thermal aging

Wang, Zixi; Zhao, Hongchang; Chen, Lei; Wu, Guo-rui; Wang, Yan; Shen, Dejiu; Wang, Mingjia

doi:10.1016/j.matchar.2019.04.002

Cited by 6 publications

(2 citation statements)

References 23 publications

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“…In addition, doping nitrogen into M 23 C 6 to form the much more stable M 23 (C, N) 6 may be another important reason. [28]…”

Section: Effect Of Nitrogen On Microstructurementioning

confidence: 99%

Nitrogen Effects on Microstructural Evolution, Fracture Behavior of Cr–Mo–V Hot‐Working Die Steel during High‐Temperature Deformation at 700 °C

Gu,

Chi,

Zhou

et al. 2023

steel research int.

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In present work, nitrogen effects on microstructural evolution, fracture behavior of Cr‐Mo‐V hot‐working die steel during high‐temperature deformation at 700 °C are systematically investigated. The results reveal that increasing N/C ratio can enhance the amounts and stability of undissolved V(C, N) and enable austenitizing temperature of steel increase from 1030 °C to 1080‐1100 °C. Adding both nitrogen and nitrogen‐substituted carbon can increase the ultimate tensile strength (UTS) at 700 °C from 380 MPa to 480‐490 MPa, but had the inverse effect on resistance to crack initiation. Nitrogen addition promotes the M23C6 nucleation locating on the boundary and decrease resistance to crack initiation. The mechanisms of nitrogen‐substituted carbon contributing to the improvement of resistance to crack initiation and high‐temperature strength could be ascribed to several reasons. First, allowed higher austenitizing temperatures and lower carbides coarsening rates delayed matrix recovery and voids formation, ensuring grain boundary strength. Next, the amounts and coarsening rate of undesirable M23C6 located on the grain boundaries were effectively decreased, reducing the crack initiation. Then, increasing desirable V(C, N) could act as strong obstacles to the crack propagation. These results contributed to the further interpretation of nitrogen mechanisms in steels worked at high temperature.This article is protected by copyright. All rights reserved.

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“…In addition, doping nitrogen into M 23 C 6 to form the much more stable M 23 (C, N) 6 may be another important reason. [28]…”

Section: Effect Of Nitrogen On Microstructurementioning

confidence: 99%

Nitrogen Effects on Microstructural Evolution, Fracture Behavior of Cr–Mo–V Hot‐Working Die Steel during High‐Temperature Deformation at 700 °C

Gu,

Chi,

Zhou

et al. 2023

steel research int.

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“…Fig 13. Comparison of thermal expansion rate between compound layer and non-nitrided matrix of SUS304.…”

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confidence: 99%

ガス窒化およびガス軟窒化の環境下でのsus304治具のミクロ組織変化と破断

Luan,

Yamamoto,

Okuyama

et al. 2024

J. Japan Inst. Metals and Materials

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The microstructural change and fracture by repeated gas nitriding and gas nitrocarburizing of SUS304 jig were investigated in this study. It was found that an oxide layer which was formed owing to high-temperature oxidation of the microstructure near the surface, was easily detached from the surface layer. Also, many micro voids in the oxide layer were observed. Beneath the oxide layer, a compound layer containing mainly nitrides was identified. A carbon diffusion region was observed in the matrix adjacent to the interface between the compound layer and the matrix. It was considered that the fine voids and uneven surfaces induced under loading stress during both treatments were the crack initiation points, which coalesced for the development of cracking. The fractured surface exhibits a sequence of brittle and ductile fracture patterns as the microstructure changes from the surface to the interior.

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Ferritic–Martensitic Steels in Power Industry: Microstructure, Degradation Mechanism, and Strengthening Methods

Jiang,

Huang,

Feng

et al. 2024

steel research int.

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Ferritic–martensitic (F–M) steels are widely used for high‐temperature pressure vessels and reactor cladding structures in power plants. The high operating temperatures and pressures, as well as the radiation environment, significantly challenge the mechanical stability of these steels. Here, the degradation mechanisms in F–M steels during creep and thermal aging under these harsh environments are reviewed. The exceptional mechanical properties of F–M steels are mainly attributed to their well‐constructed microstructures and chemical compositions. Microstructural barriers such as dislocations, solid solution atoms, and precipitates play key roles in resisting degradation. During the long‐term service, the microstructures undergo gradual evolution, resulting in a deterioration of mechanical properties at the macrolevel. In addition to the degradation mechanisms, some recent advancements in strengthening methods, including microalloying strengthening, thermomechanical treatment (TMT), and oxide dispersion strengthening, are summarized, aimed at the development of next‐generation F–M steels. The strengthening of the F–M steels is mainly achieved by enhancing the thermal stability of their microstructures. Insight into both the deterioration mechanisms and strengthening methods of F–M steels may pave the way for new approaches in developing high‐performance steels for applications in next‐generation power plants operating at ultrahigh operating temperatures and pressures.

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Evolution and its stability of M23(C,N)6 carbonitride in martensite ferritic steel during long-term thermal aging

Cited by 6 publications

References 23 publications

Nitrogen Effects on Microstructural Evolution, Fracture Behavior of Cr–Mo–V Hot‐Working Die Steel during High‐Temperature Deformation at 700 °C

Nitrogen Effects on Microstructural Evolution, Fracture Behavior of Cr–Mo–V Hot‐Working Die Steel during High‐Temperature Deformation at 700 °C

ガス窒化およびガス軟窒化の環境下でのsus304治具のミクロ組織変化と破断

Ferritic–Martensitic Steels in Power Industry: Microstructure, Degradation Mechanism, and Strengthening Methods

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