Interdiffusion in Ni-Rich, Ni-Cr-Al alloys at 1100 and 1200 °C: Part I. Diffusion paths and microstructures

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Department of Materials Science and Engineering


Interdiffusion in Ni-rich, Ni-Cr-Al diffusion couples was studied after annealing at 1100 and 1200 °C. Recession of γ′ (Ni 3Al structure), β (NiAl structure), or α (bcc) phases was also measured. Aluminum and chromium concentration profiles were measured in the γ (fcc) phase for most of the diffusion couples. The amount and location of Kirkendall porosity suggests that Al diffuses more rapidly than Cr which diffuses more rapidly than Ni in the γ phase of Ni-Cr-Al alloys. The location of maxima and minima in the concentration profiles of several of the diffusion couples indicates that both cross-term diffusion coefficients for Cr and Al are positive and that D CrAl has a greater effect on the diffusion of Cr than does D A1Cr on the diffusion of Al. The γ/γ + β phase boundary has also been determined for 1200 °C through the use of numerous γ/γ+ β diffusion couples.

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© 1987 The Metallurgical of Society of AIME. Publisher’s version of record: https://doi.org/10.1007/BF02647078

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Metallurgical Transactions A