Assessment of Ternary Multicomponent Diffusion in Alloy 22 (Ni-Cr-Mo)

Abstract:

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Diffusivity [D] matrices are reported for the ternary Ni-Cr-Mo alloy in the approximate single-phase compositional range of Hastelloy C-22 (Alloy 22), surrounding Ni-63 wt.%, Cr-22.3 wt.%, and Mo-14.7 wt.%. These data will contribute to our understanding of the long-term phase stability of Alloy 22, and its potential use as a corrosion barrier in nuclear waste packages. Experimental diffusion couple data were obtained at selected temperatures from a series of diffusion couples, and evaluated, assuming constant diffusivity. Our approach treats the process as an optimization problem that simultaneously considers concentration profile data from numerous diffusion couples surrounding a single end-point composition. We make use of the mathematical characteristics of the analytical solution to this problem, reducing the number of parameters to be fitted. The parameter fitting is accomplished using a combination of heuristic and deterministic methods. Discussion of the sources and magnitudes of uncertainty in the diffusivity values is included.

Info:

Periodical:

Edited by:

Prof. Yong Ho Sohn, C. Campbell, D. Lewis and Afina Lupulescu

Pages:

181-190

DOI:

10.4028/www.scientific.net/DDF.266.181

Citation:

A.V. Jaques and J.C. LaCombe, "Assessment of Ternary Multicomponent Diffusion in Alloy 22 (Ni-Cr-Mo)", Defect and Diffusion Forum, Vol. 266, pp. 181-190, 2007

Online since:

September 2007

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Price:

$35.00

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