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J. Zenisek, E. Kozeschnik, J. Svoboda, F.D. Fischer:
"Impact of microscopic chemical fluctuations on precipitation in interstitial / substitutional systems";
Poster: PTM 2010 Solid-Solid Phase Transformation in Inorganic Materials, Avignon; 2010-06-06 - 2010-06-11.

We investigate the role of random spatial composition fluctuations in an A-B-C alloy on the nucleation of a hypothetical (AB)-C compound, where A and B are substitutional elements, and C is an interstitial component with stronger interaction to B. The model takes into account the local atomic arrangement of A and B atoms around an arbitrary nucleation centre. The specific interfacial energy is treated as a free parameter.
Regular and random substitutional atom distributions in the same alloy are simulated. The simulation results for random and regular atomic arrangements and the effect of natural chemical fluctuations on nucleation are discussed for various values of the interfacial energy. It is shown that the chemical fluctuations can considerably facilitate nucleation and affect nucleation densities in alloys with higher values of the interfacial energy and lower mean driving force.

precipitation, nucleation barrier, chemical fluctuations