The kinetics of coarsening in the Al-Al < inf> 3 Ni System

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Department of Materials Science and Engineering


The kinetics of coarsening of the Al-Al3Ni system during the stage of coarsening during which the microstructure is nearly representative of a random array of dispersed fibers is adequately expressed by conventional kinetics, i.e. Δr 3 ≅t where r is average fiber radius and t coarsening time. The activation energy for the coarsening process is ∼315 kJ/mol and is composed of two terms: 1) the volume diffusion activation energy for nickel in the aluminum matrix and 2) the heat of solution of nickel in solid aluminum. It is pointed out that the conventional expressions for coarsening kinetics in this system can only be applied over a limited range of coarsening time since the microstructure is not generally representative of microstructures envisaged for coarsening process. Several comments and comparisons regarding the initiation of three-dimensional coarsening in this and other systems are made.

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© 1976 The Metallurgical of Society of AIME. Publisher’s version of record: https://doi.org/10.1007/BF02644047

Publication Title

Metallurgical Transactions A