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E. Kozeschnik, J. Svoboda, F. Fischer:
"Application of the thermodynamic extremal principle to solid-state precipitation";
Vortrag: Workshop Mechanics of Materials ELACTAM, Havanna (eingeladen); 22.02.2016 - 24.02.2016.

Solid-state precipitation is the phenomenon, where second phase particles form in a supersaturated matrix during thermo-mechanical treatment. The basic principles of this reaction are the nucleation and diffusion-controlled growth of particles in a multi-component matrix. The leading physical mechanisms governing the precipitation process are the formation of supercritical nuclei of the new phase (nucleation) as well as long-range diffusion of atoms towards the precipitates to support their growth. In the presentation, a mean-field approach is introduced by which the complex problem of solid-state precipitation can be formulated in a convenient way. Application of the thermodynamic extremal principle brings the free energy and dissipation expressions of the mean-field formulation into a direct relation and finally delivers rate equations that describe the solid-state precipitation process in a very elegant and computationally efficient way. In the presentation, the TEP is briefly discussed and it is demonstrated that this principle offers a huge potential for application also to equivalent problems in mechanical and metallurgical engineering.

precipitation