In-situ Observation of Dislocation Motion and Its Mobility in Fe-Mo and Fe-W Solid Solutions at High Temperatures.

Terada, Daisuke; Yoshida, Fuyuki; Nakashima, Hideharu; Abe, Hiroshi; Kadoya, Y.

doi:10.2355/isijinternational.42.1546

Cited by 20 publications

(14 citation statements)

References 14 publications

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“…[22], a mean dislocation velocity of 2 × 10 −15 m/s is obtained. This value is much lower than the dislocation velocity of 2.3 × 10 −3 m/s evaluated by in-situ TEM observations in a Fe-Mo alloy (0.001C-1.2Mo-0.02N-0.4Si, wt.%) at 738 • C, under a stress actiong on dislocations of 5.3 MPa [23]. This is probably mainly due to different testing temperatures and different levels of stress.…”

Section: Dislocation Densitymentioning

confidence: 57%

Evolution of dislocation density, size of subgrains and MX-type precipitates in a P91 steel during creep and during thermal ageing at 600C for more than 100,000h

Panait

Zielińska‐Lipiec

Kozieł

et al. 2010

Materials Science and Engineering: A

209

101

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a b s t r a c tThere are rather few quantitative data on the microstructure of the 9-12%Cr heat resistant steels after long-term creep. This paper presents results of the quantitative measurement of the size of MX precipitates, subgrain size and dislocation density in a P91 steel that had been creep tested for 113,431 h at 600 • C. The same measurements were conducted in the same P91 steel in the as received conditions.Transmission electron microscopy investigations were conducted using thin foils and revealed a decrease in dislocation density and an increase in subgrain size after creep exposure. MX carbonitrides are very stable during thermal and creep exposure of P91 steel at 600 • C up to 113,431 h.Electron backscatter diffraction (EBSD) investigations also revealed a significant change in the substructure of the steel after creep exposure.

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Section: Dislocation Densitymentioning

confidence: 57%

Evolution of dislocation density, size of subgrains and MX-type precipitates in a P91 steel during creep and during thermal ageing at 600C for more than 100,000h

Panait

Zielińska‐Lipiec

Kozieł

et al. 2010

Materials Science and Engineering: A

209

101

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“…The regression using Equation gives a good fit to the experimental measurements, and the resulting value of 54 844 K for k 3 corresponds to an activation energy of 456 000 J mol −1 . This is substantially larger than the value of 224 200 J mol −1 adopted from Terada et al for Mo diffusion. A more detailed evaluation of k 2 and k 3 is, however, difficult due the complexity of the parent system.…”

Section: Discussionmentioning

confidence: 54%

“…Calculations using the LSW theory require values for the diffusion coefficient, surface energy, solubility, molar volume, and volume fraction coefficient . The computed results show considerably slower growth than experimentally measured, even with a volume fraction coefficient k ( f V ) = 4.…”

Section: Discussionmentioning

confidence: 91%

“…The calculations were done assuming Mo diffusion in ferrite to be rate determining for the growth, the slowest diffusing of the substitutional species in the alloy. This can be described according to Terada et al as

D = 6.63 \times 10^{- 5} e^{- 224200 / R T} {normalm}^{2} {normals}^{- 1}

. The value for the surface energy σ was chosen as 0.56 J m −2 , using a value for incoherent αFe–γFe given by Martin et al from Smith .…”

Section: Theoretical Predictionsmentioning

confidence: 99%

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An Experimental and Theoretical Evaluation of Microstructure Coarsening in Duplex Stainless Steels

Wessman¹,

Wilson

Hertzman

et al. 2013

steel research int.

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The coarsening of duplex stainless steel microstructures at temperatures above 10008C was investigated experimentally and theoretically. Hot-rolled duplex 2205 and superduplex 2507 samples were heat treated isothermally at 11008C up to 700 h, and also between 1000 and 12508C for 24 h. The ferrite content and the microstructure coarseness, quantified by the measured austenite spacing, AS, were evaluated. It was found that the observed coarsening could be described using Ostwald ripening theory expressed as AS n À AS n 0 ¼ kt, where AS 0 is austenite spacing of the as-delivered material, k the rate constant, n the exponent, and t the heat treatment time. Using regression analysis, n and k were evaluated and the resulting predictions compared with literature theories and results. The results were also calculated according to the original Lifshitz, Slyozov, Wagner (LSW) theory with parameters taken from literature, as well as with the Dictra software for diffusion and growth in multicomponent systems. The calculations indicated that while the classical LSW theory failed to give a good description of the experimental results, the Dictra simulations proved very accurate, even though systems of equal ferrite and austenite content are considerably outside the intended range of applicability of the software.

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“…In case of 316 LN steel, Praveen et al [24] reported the dislocation glide velocity to be in the range of ~5 ×10 -9 -5 ×10 -8 m/s for 120-225 MPa at 650 o C. Bonora et al [26] reported the average dislocation velocity to be in the range of ~2 ×10 -12 -3.25 ×10 -8 m/s. In case of Fe-0.7W alloys, Terada et al [27] reported the dislocation velocity to be ~3.25 ×10 -8 m/s for 720 o C / 3.8 MPa. In case of Fe-0.7Mo alloys, Terada et al [27] reported the dislocation velocity to be ~ 2.3 ×10 -8 m/s for 738 o C / 5.3 MPa.…”

Section: Resultsmentioning

confidence: 99%

Creep curve modelling of Austenitic Steel 316LN

Kumar

Yadav

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Physical based creep models that elucidate the creep deformation behaviour with ongoing microstructural evolution can be a useful tool for the components life assessment as well as the design of improved materials, deployed at high temperature and pressure. In this research work, a creep model that is a combination of physical based model and CDM approach is employed to predict the creep curves of steel 316LN. The microstructure based variables those are different dislocation densities (mobile and forest) are the input parameters. The model provides a provision for the assessment of each microstructural variable, in each time step of the creep deformation. Consequently, other than creep curves, the model also demonstrates the evolution of dislocation density (mobile and forest), dislocation velocity, dislocation mobility and mean free path. Initial values of input parameters (various dislocation densities and mean free path) are obtained from the literature for initializing the model. It can be observed that the predicted creep curves are in reasonable agreement with experimental ones and the evolution of other involved parameters is discussed thoroughly.

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In-situ Observation of Dislocation Motion and Its Mobility in Fe-Mo and Fe-W Solid Solutions at High Temperatures.

Cited by 20 publications

References 14 publications

Evolution of dislocation density, size of subgrains and MX-type precipitates in a P91 steel during creep and during thermal ageing at 600C for more than 100,000h

Evolution of dislocation density, size of subgrains and MX-type precipitates in a P91 steel during creep and during thermal ageing at 600C for more than 100,000h

An Experimental and Theoretical Evaluation of Microstructure Coarsening in Duplex Stainless Steels

Creep curve modelling of Austenitic Steel 316LN

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