Predicting diffusion paths and interface motion in γ/γ + β, Ni-Cr-Al diffusion couples

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Department of Materials Science and Engineering


A simplified model has been developed to predict β recession and diffusion paths in ternary γ/γ + β diffusion couples (γ: fcc, β: NiAl structure). The model was tested by predicting β recession and diffusion paths for four γ/γ + β, Ni-Cr-Al couples annealed for 100 hours at 1200 °C. The model predicted β recession within 20 pct of that measured for each of the couples. The model also predicted shifts in the concentration of the y phase at the γ/γ + β interface within 2 at. pct Al and 6 at. pct Cr of that measured in each of the couples. A qualitative explanation based on simple kinetic and mass balance arguments has been given which demonstrates the necessity for diffusion in the two-phaseregion of certain γ/γ + β, Ni-Cr-Al couples.

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© 1987 The Metallurgical of Society of AIME. Publisher’s version of record: https://doi.org/10.1007/BF02647080

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Metallurgical Transactions A