Interdiffusion in γ (face-centered cubic) Ni-Cr-X (X=Al, Si, Ge, or Pd) alloys at 900 °C

Garimella, N.; Brady, Michael P.; Sohn, Yongho

doi:10.1007/bf02736570

Cited by 11 publications

(19 citation statements)

References 29 publications

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“…(3) and (6) provide independent relations when the composition ranges are selected to include non-linear segments of the profiles. This analysis method to determine average ternary interdiffusion coefficients has been directly employed in various studies [3,[50][51][52][53][54][55][56][57][58]. In addition, the independence of Eqs.…”

Section: Determination Of Ternary Interdiffusion Coefficientsmentioning

confidence: 99%

Effects of Ir or Ta Alloying Addition on Interdiffusion of L12–Ni3Al

et al. 2008

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Section: Determination Of Ternary Interdiffusion Coefficientsmentioning

confidence: 99%

Effects of Ir or Ta Alloying Addition on Interdiffusion of L12–Ni3Al

et al. 2008

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“…diffusion against its own concentration gradient, has been observed for both Ni-Cr-Al 26 and Ni-Cr-Si 56,57 systems. Garimella et al 56,57 reported enhanced chromium diffusion from Ni-Cr-X (X5Al, Si) alloys into pure nickel compared to the nickel2NiCr diffusion couple, i.e. chromium penetration into nickel occurred more rapidly in concurrent Cr and Si/Al gradients than only in a single Cr gradient.…”

Section: Chromium Depletion Profilesmentioning

confidence: 99%

“…Internal precipitation of alumina (and/or silica) beneath chromia scales promotes enhanced chromium diffusion towards the surface and a higher Cr supply at the scalealloy-interface thereby providing better oxidation/corrosion resistance with respect to the occurrence of for example breakaway oxidation. 26,56,58 …”

Section: Modeling External and Internal Oxidationmentioning

confidence: 99%

Modelling compositional changes in nickel base alloy 602 CA during high temperature oxidation

Chyrkin

Sloof

Pillai

et al. 2015

Materials at High Temperatures

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The high chromium nickel base alloy 602 CA is used as construction material for high temperature components in aggressive environments such as gas burners or heat exchangers. The high temperature oxidation behaviour of this alloy is characterised by the formation of an external Cr 2 O 3 scale and internal precipitation of alumina. The main goal of the present investigation was to elucidate the effect of aluminum on the subscale chromium depletion phenomena. The chromium concentration profiles were found to be flat and sometimes even increasing towards the oxide-alloy interface. The experimental observations were interpreted in terms of alloy thermodynamics, i.e. effect of oxidation induced compositional changes on chemical potentials of the alloy constituents. The concentration profiles in alloy 602 CA observed during high temperature exposure were modelled using the CALPHAD approach for thermodynamic and kinetic calculations. Thermodynamic calculations revealed that the Al depletion in the alloy subsurface due to internal alumina precipitation leads to enhanced Cr diffusion towards the alloy surface.

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“…René-88 contains substantially more Cr than CMSX-10. Chromium is known to affect Al activity [42,43] and thus its diffusion [37] in Ni-base alloys. Therefore Cr was also added to the list of elements, which are subject to composition reduction analysis.…”

Section: Interdiffusion Profilesmentioning

confidence: 99%

Modeling Interdiffusion Processes in CMSX-10/Ni Diffusion Couple

Chyrkin

Epishin

Pillai

et al. 2016

J. Phase Equilib. Diffus.

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A diffusion couple between directionally solidified nickel and the single crystal Ni-base superalloy CMSX-10 was produced by hot pressing in vacuum. The diffusion couples were heat treated at temperatures between 1050 and 1250°C. The exposed samples were characterized by SEM/EBSD/EPMA. The interdiffusion results in dissolution of the c¢-Ni 3 Al in the superalloy and in growth of nickel grains towards CMSX-10. Rapid diffusion of aluminum from the superalloy into pure nickel leads to a significant formation of pores in the superalloy. The interdiffusion processes were modelled using the finite-element simulation software DICTRA with the databases TCNi5 and MobNi2, tailored specially for Ni-base superalloys. The effect of alloying elements on the interdiffusion profiles is discussed in terms of alloy thermodynamics. The calculated element concentration profiles are in good agreement with the EPMA measurements. The interdiffusion modeling correctly predicts the shapes of the concentration profiles, e.g. kinks on the Al and Ti profiles in the vicinity of the original interface in the joint. The calculation predicts with reasonable accuracy the extent and the location of the Kirkendall porosity.

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Interdiffusion in γ (face-centered cubic) Ni-Cr-X (X=Al, Si, Ge, or Pd) alloys at 900 °C

Cited by 11 publications

References 29 publications

Effects of Ir or Ta Alloying Addition on Interdiffusion of L12–Ni3Al

Effects of Ir or Ta Alloying Addition on Interdiffusion of L12–Ni3Al

Modelling compositional changes in nickel base alloy 602 CA during high temperature oxidation

Modeling Interdiffusion Processes in CMSX-10/Ni Diffusion Couple

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