On the microstructural development of the tempered martensitic Cr-steel P 91 during long-term creep—a comparison of data

Polcik, P.; Sailer, T.; Blum, W.; Straub, Stefan; Buršı́k, Jiřı́; Orlová, A.

doi:10.1016/s0921-5093(98)00887-9

Cited by 49 publications

(20 citation statements)

References 6 publications

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“…13a). This is consistent with previous observations from the martensitic steels in which the substructure becomes more refined at an higher applied stress in the dislocation-climbcontrolled creep regime [22,49,50].…”

Section: Microstructural Characterisation Of Creep Exposed Materialssupporting

confidence: 93%

Investigation of short-term creep deformation mechanisms in MarBN steel at elevated temperatures

Benaarbia

Sun

et al. 2018

Materials Science and Engineering: A

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This paper reports the short-term creep behaviour at elevated temperatures of a MarBN steel variant. Creep tests were performed at three different temperatures (625°C, 650°C and 675°C) with applied stresses ranging from 160 MPa to 300 MPa, and failure times from 1 to 350 h. Analysis of the macroscopic creep data indicates that the steady-state creep exhibits a power-law stress dependence with an exponent of 7 and an activation energy of 307 kJ mol, suggesting that dislocation climb is the dominant rate-controlling creep mechanism for MarBN steel. Macroscopic plastic instability has also been observed, highlighted by an obvious necking at the rupture region. All the macroscopic predictions have been combined with microstructural data, inferred from an examination of creep ruptured samples, to build up relations between macroscopic features (necking, damage, etc.), and underlying microstructural mechanisms. Analysis of the rupture surfaces has revealed a ductile fracture mode. Electron Backscatter Diffraction (EBSD) analysis near to the rupture surface has indicated significant distortion and refinement of the original martensitic substructure, which is evidence of long-range plastic flow. Dislocation pile-ups and tangles from TEM were also observed near substructure boundaries and precipitate particles. All of these microstructural observations suggest that creep is influenced by a complex interaction between several elements of the microstructure, such as dislocations, precipitates and structure boundaries. The calculated stress exponent and activation energy have been found to agree quantitatively with the highlighted microstructural features, bearing some relationships to the true observed creep microstructures.

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Section: Microstructural Characterisation Of Creep Exposed Materialssupporting

confidence: 93%

Investigation of short-term creep deformation mechanisms in MarBN steel at elevated temperatures

Benaarbia

Sun

et al. 2018

Materials Science and Engineering: A

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“…Carbide coarsening and precipitation of the Z-phase might be related to lath recovery as they lead to a decrease in the dislocation pinning effect of carbides and MX particles (Iwanaga et al, 1998). The process of lath martensite recovery is usually described as subgrain nucleation and growth, where the kinetics of subgrain growth which can be well represented byḋ = Aσ −p , where d is the subgrain size and σ the principal stress (Orlová et al, 1998;Polcik et al, 1999). In addition, Laves phase precipitation induces a loss of solid solution strengthening effect of molybdenum and affects the material creep strength (Senior, 1989;Stocker et al, 2002).…”

Section: Ageing and Softening Effectsmentioning

confidence: 99%

Creep failure model of a tempered martensitic stainless steel integrating multiple deformation and damage mechanisms

2005

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International audienceA new model considering both deformation and damage evolution under multiple viscoplastic mechanisms is used to represent high temperature creep deformation and damage of a martensitic stainless steel in a wide range of load levels. First, an experimental database is built to characterise both creep flow and damage behaviour using tests on various kinds of specimens. The parameters of the model are fitted to the results and to literature data for long term creep exposure. An attempt is made to use the model to predict creep time to failure up to 105 h

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“…In this figure, the experimental observation for base material without any additional heat treatment is given for comparison. [8] The experimental data for the cross-weld sample has been evaluated in the fine-grained region of the heat-affected zone, [4] and it has been assumed to be equal to the 1173 K (900°C) heat treatment temperature.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…[4] For base material, the initial subgrain size is approximately 0.6 lm and increases during creep depending on loading and temperature. [8] Other studies on weld-simulated samples by heat treatment at 5 minutes and 1123 K (850°C) show an increase in average subgrain area from 0.58 to 0.98 lm 2 for creep testing at 873 K (600°C) and 140 MPa. [9] In the same study, the values for base material increases from 0.31 to 0.73 lm 2 at identical conditions.…”

Section: Introductionmentioning

confidence: 92%

Modeling Creep Strength of Welded 9 to 12 Pct Cr Steels

Magnusson

Sandström

2010

Metall Mater Trans A

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The influence of weld-simulated heat treatments of 9 to 12 pct steels is evaluated by a fundamental model for creep. The heat-affected microstructure is predicted by considering particle coarsening, particle dissolution, and subgrain coarsening. Particle coarsening is predicted for a multicomponent system, showing significant M 23 C 6 coarsening in the bcc matrix. Dissolution simulations of MX and M 23 C 6 are performed by considering a size distribution of particles, indicating that the smallest particles can be dissolved already at relatively low welding temperatures. Recovery in dislocation networks will take place due to the coarser particles. Creep rate modeling is performed based on the heat-affected microstructure, showing strength reduction of weld-simulated material by 12 pct at 1123 K (850°C) and 30 pct at 1173 K (900°C). The main cause of this degradation is believed to be the loss of the smallest carbonitrides.

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On the microstructural development of the tempered martensitic Cr-steel P 91 during long-term creep—a comparison of data

Cited by 49 publications

References 6 publications

Investigation of short-term creep deformation mechanisms in MarBN steel at elevated temperatures

Investigation of short-term creep deformation mechanisms in MarBN steel at elevated temperatures

Creep failure model of a tempered martensitic stainless steel integrating multiple deformation and damage mechanisms

Modeling Creep Strength of Welded 9 to 12 Pct Cr Steels

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