The strengthening effect of (Ni,Fe)Al precipitates on the mechanical properties at high temperatures of ferritic Fe–Al–Ni–Cr alloys

Stallybrass, C. O.; Schneider, A.; Sauthoff, Gerhard

doi:10.1016/j.intermet.2004.07.048

Cited by 117 publications

(91 citation statements)

References 12 publications

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“…The replacement of some Cr with Al as alloying elements are of great interest especially for development of FeNi-Al based alloys 14 as these materials are relatively cheaper, lighter and stronger as a result of the dispersion of intermetallic compound precipitates of B2-(Fe,Ni)Al 15,16 . Investigation on the effect of aluminum addition on the microstructural evolution of Fe-Ni-Al alloys at high temperatures has been recently conducted 17 .…”

Section: Development Of B2-(feni)al In α and γ Matrixmentioning

confidence: 99%

Alloys developed for high temperature applications

Basuki

Prajitno

Muhammad

2017

AIP Conference Proceedings

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Co-based alloys design based on first-principles calculations: Influence of transition metal and rare-earth alloying element on stacking fault energy AIP Conference Proceedings 1805, 060004 (2017) Abstract. Alloys used for high temperatures applications require combinations of mechanical strength, microstructural stability and corrosion/oxidation resistance. Nickel base superalloys have been traditionally the prime materials utilized for hot section components of aircraft turbine engines. Nevertheless, due to their limited melting temperatures, alloys based on intermetallic compounds, such as TiAl base alloys, have emerged as high temperature materials and intensively developed with the main aim to replace nickel based superalloys. For applications in steam power plants operated at lower temperatures, ferritic high temperature alloys still attract high attention, and therefore, development of these alloys is in progress. This paper highlights the important metallurgical parameters of high temperature alloys and describes few efforts in the development of Fe-Ni-Al based alloys containing B2-(Fe,Ni)Al precipitates, oxide dispersion strengthening (ODS) ferritic steels and titanium aluminide based alloys include important protection system of aluminide coatings.

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Section: Development Of B2-(feni)al In α and γ Matrixmentioning

confidence: 99%

Alloys developed for high temperature applications

Basuki

Prajitno

Muhammad

2017

AIP Conference Proceedings

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“…7(a), the endothermic peak at a temperature of ~ 923 K is most likely the solvus temperature of the secondary NiAl precipitates [27]. However, the ferromagnetic to paramagnetic transition temperature (T c ) of the Fe-Al-Ni system was reported [104] to be also between 873 and 973 K. Therefore, further studies will need to be carried out to verify this phase transition.…”

Section: B331 Phase Transformationmentioning

confidence: 99%

“…Fe-Ni-Al-Cr-based ferritic alloys, containing fine dispersions of coherent, nanoscale (B2-NiAl based) precipitates in a bcc Fe matrix [26][27][28][29]. To optimize the properties of ferritic alloys for such high-temperature applications, it is desirable to identify slow-diffusing solute additions that can act to reduce precipitate-coarsening kinetics, and help optimize creep strengths [25,29].…”

Section: B11 Introductionmentioning

confidence: 99%

Computational Design and Prototype Evaluation of Aluminide-Strengthened Ferritic Superalloys for Power-Generating Turbine Applications up to 1,033 K

Liaw¹,

Ghosh²,

Asta³

et al. 2010

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The objective of the proposed research is to utilize modern computational tools, integrated with focused experiments, to design innovative ferritic NiAl-strengthened superalloys for fossil-energy applications at temperatures up to 1,033 K. Specifically, the computational alloy design aims toward (1) a steady-state creep rate of approximately 3 x 10 -11 s -1 at a temperature of 1,033 K and a stress level of 35 MPa, (2) a ductility of 10% at room temperature, and (3) good oxidation and corrosion resistance at 1,033 K.The research yielded many outstanding research results, including (1) impurity-diffusion coefficients in α Fe have been calculated by first principles for a variety of solute species; (2) the precipitates were characterized by the transmission-electron microscopy (TEM) and analytical-electron microscopy (AEM), and the elemental partitioning has been determined; (3) a bending ductility of more than 5% has been achieved in the unrolled materials; and (4) optimal compositions with minimal secondary creep rates at 973 K have been determined. Impurity diffusivities in α Fe have been calculated within the formalisms of a harmonic transition-state theory and Le Claire nine-frequency model for vacancy-mediated diffusion. Calculated diffusion coefficients for Mo and W impurities are comparable to or larger than that for Fe self-diffusion. Calculated activation energies for Ta and Hf impurities suggest that these solutes should display impurity-diffusion coefficients larger than that for self-diffusion in the body-centered cubic Fe. Preliminary mechanical-property studies identified the alloy Fe-6.5Al-10Ni-10Cr-3.4Mo-0.25Zr-0.005B (FBB-8) in weight percent (wt.%) for detailed investigations. This alloy shows precipitation of NiAl particles with an average diameter of 130 nm.In conjunction with the computational alloy design, selected experiments are performed to investigate the effect of the Al content on the ductility and creep of prototype Fe-Ni-Cr-Al-Mo alloys. Three-point-bending experiments show that alloys containing more than 5 wt.% Al exhibit poor ductility (< 2%) at room temperature, and their fracture mode is predominantly of a cleavage type. Two major factors governing the poor ductility are (1) the volume fraction of NiAl-type precipitates, and (2) the Al content in the α-Fe matrix. A bend ductility of more than 5% can be achieved by lowering the Al concentration to 3 wt.% in the alloy.The alloy containing about 6.5 wt.% Al is found to have an optimal combination of hardness, ductility, and minimal creep rate at 973 K. A high volume fraction of precipitates is responsible for the good creep resistance by effectively resisting the dislocation motion through Orowan-bowing and dislocation-climb mechanisms. The effects of stress on the creep rate have been studied. With the threshold-stress compensation, the stress exponent is determined to be 4, indicating power-law dislocation creep. The threshold stress is in the range of 40 ~ 53 MPa. The addition of W can significantly reduce the secondary c...

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“…Sin embargo, todos estos trabajos encontraron que la presencia de una fv diferente de cero no altera el exponente temporal predicho por la teoría LSW, pero sí altera las amplitudes de la ley de crecimiento, es decir, predicen distribuciones de tamaño de partícula más anchas y más simétricas que las que predice LSW conforme la fv aumenta [20] . Por otra parte, la resistencia mecánica a temperaturas relativamente altas en las aleaciones base hierro se basa, principalmente, en la presencia de precipitados coherentes β', del tipo (NiAl) con una estructura B2 (CsCl), finamente dispersos en la matriz [21][22][23] . Además, este compuesto intermetálico le proporciona una excelente resistencia a la oxidación a temperaturas cercanas a los 1.000 °C [24] .…”

Section: I In Nt Tr Ro Od Du Uc Cc Ci Ió óN Nunclassified

Coarsening kinetics of coherent precipitates in Fe-10 % Ni-15 % Al alloy

et al. 2008

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Las propiedades mecánicas de los materiales metálicos endurecibles por precipitación están íntimamente relacionadas con la morfología, distribución espacial, fracción volumétrica y tamaño de partículas de una segunda fase [1 y 2] . Un método efectivo para controlar dichas partículas consiste en tratamientos térmicos de envejecido [3 y 4] . Generalmente, en sistemas de aleación que contienen precipitados que provocan su endurecimiento, p. e., superaleaciones base níquel y, en ausencia de esfuerzos externos, el equilibrio termodinámico se obtiene reduciendo la energía libre interfacial total mediante un proceso de transferencia de masa difusional de regiones de alta curvatura interfacial hacia regiones de baja curvatura interfacial [5 y 6] . Este proceso es, comúnmente, llamado engrosamiento o maduración de Ostwald [7] . Por lo tanto, el proceso de engrosamiento ocurre por la disolución de partículas pequeñas y su transferencia de masa a partículas grandes [8 y 9] . Una de las primeras teorías de engrosamiento de precipitados fue desarrollada por Lifshitz, Slyosov [10] y Wagner [11] , conocida como la teoría LSW. Dicha teoría considera sistemas C Ci in né ét ti ic ca a d de e e en ng gr ro os sa am mi ie en nt to o d de e p pr re ec ci ip pi it ta ad do os s c co oh he er re en nt te es s e en n l la a a al le ea ac ci ió ón n F Fe e--1 10 0 % % N Ni i--1 15 5 % % A Al l (N. Cayetano-Castro * , H.J. Dorantes-Rosales * , V.M. López-Hirata * , J.J. Cruz-Rivera ** , J. Moreno-Palmerin * y J.L. González-Velázquez * R Re es su um me en n La cinética de engrosamiento y la evolución morfológica de precipitados coherentes β' (Fe, Ni)Al en una matriz ferrítica se estudió en la aleación Fe-10 % Ni-15 % Al. Se solubilizaron muestras a 1.100 °C por 24, y posteriormente, se envejecieron a 750, 850 y 920 °C por diferentes tiempos. Los resultados de DRX, MEB y MET mostraron la descomposición, α sss →α+β, durante su envejecido. La distribución de precipitados dentro del grano cambia, gradualmente, de aleatoria a un alineamiento preferencial sobre las direcciones cristalográficas <100> de la matriz. Asimismo, la evolución morfológica de los precipitados fue: esféricos → cúbicos → paralelepípedos → placas. La variación del tamaño de partícula, r 3 , y la densidad de precipitados en función del tiempo se comportan linealmente, como lo predice la teoría de Lifshitz, Slyosov y Wagner (LSW) para el engrosamiento controlado por difusión. La cinética de crecimiento (K) se incrementó a temperaturas de envejecido mayores. La energía de activación para el proceso de engrosamiento fue de alrededor de 220 kJ/mol. P Pa al la ab br ra as s c cl la av ve eEngrosamiento. Transformaciones de fase. Aleación Fe-Ni-Al. Precipitados coherentes. Envejecido.C Co oa ar rs se en ni in ng g k ki in ne et ti ic cs s o of f c co oh he er re en nt t p pr re ec ci ip pi it ta at te es s i in n F Fe e--1 10 0 % % N Ni i--1 15 5 % % A Al l a al ll lo oy y A Ab bs st tr ra ac ct tThe coarsening kinetics and the morphology evolution of the coherent β' (Fe, Ni)...

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The strengthening effect of (Ni,Fe)Al precipitates on the mechanical properties at high temperatures of ferritic Fe–Al–Ni–Cr alloys

Cited by 117 publications

References 12 publications

Alloys developed for high temperature applications

Alloys developed for high temperature applications

Computational Design and Prototype Evaluation of Aluminide-Strengthened Ferritic Superalloys for Power-Generating Turbine Applications up to 1,033 K

Coarsening kinetics of coherent precipitates in Fe-10 % Ni-15 % Al alloy

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