A THEORY OF MIXTURES FOR HETEROGENEOUS SOLIDS AND ITS APPLICATION TO SPINODAL DECOMPOSITION AND COARSENING

摘要

A theory of mixtures for heterogeneous solids is presented. For this purpose methods for exploitation of the second law of thermodynamics (2nd law) are revisited. The constitutive equations for, e.g., the entropy flux and the diffusion flux, are formulated as a consequence of a non-negative entropy production and it is briefly explained, how local (thermo-) mechanical strains modify the free energy and, consequently, the chemical potentials. All steps are illustrated for a simple mixture and for a multi-component system with two phases. The equations are finally specialized and examined numerically for the binary alloy Ag-Cu where spinodal decomposition and coarsening has been observed experimentally.