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J. Svoboda, Y.V. Shan, E. Kozeschnik, F.D. Fischer:
"A thermokinetic model for Mg-Si couple formation in Al-Mg-Si alloys";
Modelling and Simulation in Materials Science and Engineering, 24 (2016), 1 - 16.

Mg-Si couples formed from atomic Mg and Si represent the first step in Mg-Si cluster formation
in a dilute Al-Mg-Si system. Based on the thermodynamic extremal principle, a kinetic
model for Mg-Si couple formation is developed. The model utilizes the trapping concept for
the calculation of Gibbs energy of the non-equilibrium system and provides a generalized
(multiplicative) form of the Oriani equation for description of the equilibrium state. The dissipation
in the system accounts for diffusion of both Mg and Si atoms in the lattice.
The model is compared with the classical Lidiard and Howard equilibrium theory. Some
demonstrative examples are presented. Finally the model is applied to an experimentally studied
system. Good quantitative agreement with quenching experiments is obtained, if, simultaneously,
the impact of excess quenched-in vacancies and their gradual annihilation in the
system, which has been already treated in a previous paper, are accounted for. The model is
generally applicable for any couple (and pair) formation.

aluminium alloys, cluster assisted nucleation, kinetics, bulk diffusion, thermodynamic modelling

http://dx.doi.org/10.1088/0965-0393/24/3/035021