A thermodynamic model of the Z-phase Cr(V, Nb)N

Danielsen, Hilmar Kjartansson; Hald, John

doi:10.1016/j.calphad.2007.04.001

Cited by 85 publications

(65 citation statements)

References 11 publications

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“…[3] Thermodynamic calculations also show Cr to be the most important element, and this is the main difference between Cr(V,Nb)N Z-phase and (V,Nb)N MX. [4] The results show that the Z-phase precipitation speed is fastest at 923 K (650°C) for the 12CrVNbN alloy, which is consistent with time-temperature-precipitation (TTP) maps for Z-phase formation in 9 to 12 pct Cr commercial steels. [14] The Z-phase precipitation is much slower in the 9CrVNbN alloy at all temperatures, but it occurs fastest at 873 K (600°C) compared to the other temperatures.…”

Section: Resultssupporting

confidence: 76%

“…The first alloy, 12CrVNbN, was designed for a fast precipitation of Z-phase using a thermodynamic model, [4] as the precipitation process could otherwise take decades.…”

Section: Methodsmentioning

confidence: 99%

“…Thermodynamic modeling has shown the main driving force for Z-phase precipitation to be the Cr content dissolved in the matrix. [4] Investigations by electron microscopy have revealed the nucleation of Z-phase to be a diffusion of Cr atoms from the matrix into existing MX particles, physically transforming them into Z-phase. [5] The effects of Z-phase on the creep strength of 12 pct Cr steels has been well described because of the relatively fast precipitation, but recent investigations of commercial 9 pct Cr steel grades have indicated that the Z-phase might also affect these steels within their expected service life.…”

Section: Hilmar K Danielsen Paolo Emilio DI Nunzio and John Haldmentioning

confidence: 99%

See 2 more Smart Citations

Kinetics of Z-Phase Precipitation in 9 to 12 pct Cr Steels

Danielsen

Nunzio

Hald

2013

Metall Mater Trans A

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Section: Resultssupporting

confidence: 76%

“…The first alloy, 12CrVNbN, was designed for a fast precipitation of Z-phase using a thermodynamic model, [4] as the precipitation process could otherwise take decades.…”

Section: Methodsmentioning

confidence: 99%

Section: Hilmar K Danielsen Paolo Emilio DI Nunzio and John Haldmentioning

confidence: 99%

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Kinetics of Z-Phase Precipitation in 9 to 12 pct Cr Steels

Danielsen

Nunzio

Hald

2013

Metall Mater Trans A

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“…The experimental results provided by Dimmler et al [16] and Hättestrand et al [13] also showed that the precipitated volume fraction of Laves-phase in steel P92 aged for 10000 h at 923 K is close to 1.0%. The calculated value is obtained at equilibrium which the Z-phase [Cr（V,Nb）N] forms and fully replaces the MX [（V,Nb）(C,N)] carbonitride, however, no Z-phase is observed during aging at 923 K up to 8000 h. Danielsen [17]have reported observed quantity of Z-phase is still low in P92 steel even after being exposured at 923K for 31000 h. Thus, the …”

Section: Quantitative Results Of the Laves-phasementioning

confidence: 99%

Laves-phase evolution during aging in 9Cr-1.8W-0.5Mo-VNb steel for USC power plants

Wang

et al. 2015

Materials Chemistry and Physics

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-Laves-phase precipitation and coarsening of tungsten strengthened 9% Cr steel under thermal aging at 923K up to 8000 h was reported in this paper, where the information of the evolution of mean particle size, the number density, the volume fraction of Laves-phase precipitates and the partition coefficients of W and Mo in the matrix over the aging time were determined. The change of hardness over time was also measured. The main results of this investigation were: 1) Laves-phase nucleates and grows rapidly on grain boundaries and lath boundaries within the first 1,500 h of aging time; 2) the coarsening of Laves-phase is much faster than that of M 23 C 6 carbides, meanwhile it demonstrates the two stages characteristics and kinetics of Laves-phase nucleation and growth which were determined experimentally; 3)The precipitation of Laves-phase produces a pronounced matrix depletion of W and Mo atoms; and 4) The precipitated Laves-phase gives rise to weaker precipitation strengthening in comparison with M 23 C 6 carbides, and causes the loss of hardenss and creep strength due to the Corresponding author. Tel.: +86 13554693820; fax: +86 02768772253. E-mail address: wxue2011@whu.edu.cn (Xue Wang) 2 depletion of Mo and W from the solid solution. This paper contributes to the knowledge of kinetics of Laves-phase precipitation and coarsening, as well as understanding the creep damage broadly.

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“…There are many further examples of applying CALPHAD for ferritic boiler steels [21][22][23]. The growth, dissolution, and coarsening of precipitates during long-term service at high temperatures is also tackled by various authors using DICTRA [24][25][26][27][28].…”

Section: Kineticsmentioning

confidence: 99%

Application of the Calphad Method for Ferritic Boiler Steels

Schneider¹

2016

TMM

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Some applications of the CALPHAD method are shown with reference to seamless tubes and pipes for high-temperature service in power plants. The focus is on concepts on the improvement of creep strength. In view of developing or improving steels for the application in conventional power plants, various elements have been tested with respect to a controlled precipitation of chromium carbides, carbonitrides and the intermetallic Laves phase.The kinetic simulations are focussed on diffusion-controlled transformations during heat-treatment and application in the power plant. A key-issue is to include important aspects such as nucleation density (in terms of pre-defined cell sizes of the model), growth, and dissolution of precipitates. Keywords: Steel; CALPHAD; Boiler; Diffusion simulation; Microstructure. APLICAÇÃO DO MÉTODO CALPHAD A AÇOS FERRÍTICOS PARA CALDEIRAS ResumoAlgumas aplicações do método CALPHAD a tubulações para aplicação a alta temperatura em plantas termoelétricas de alta temperatura são apresentadas. O trabalho é focalizado no desenvolvimento de concepções que resultem em aumento da resistência a fluência. Visando desenvolver e aprimorar aços para a aplicação em usinas térmicas convencionais vários elementos de liga foram investigados com vistas a precipitação controlada de carbonetos de cromo, carbonitretos e a fase intermetálica de Laves. As simulações cinéticas são focadas em transformações controladas por difusão que ocorrem durante o tratamento térmico e durante a aplicação do aço nas usinas. Um ponto chave é a inclusão de aspectos importantes como a densidade de núcleos (expressa como um tamanho de célula pré-definido no modelo), o crescimento e a dissolução dos precipitados. Palavras-chave: Aço; CALPHAD; Caldeiras; Simulação de difusão; Microestrutura.

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A thermodynamic model of the Z-phase Cr(V, Nb)N

Cited by 85 publications

References 11 publications

Kinetics of Z-Phase Precipitation in 9 to 12 pct Cr Steels

Kinetics of Z-Phase Precipitation in 9 to 12 pct Cr Steels

Laves-phase evolution during aging in 9Cr-1.8W-0.5Mo-VNb steel for USC power plants

Application of the Calphad Method for Ferritic Boiler Steels

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