Microstructure modeling
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| One of our most energetic efforts at the moment involves getting realistic metamorphic processes coded in Elle. We have developed a process whereby sites of porphyroblast nucleation are determined by factors such as grain boundary type (e.g., triple junction), mineralogy (e.g., a neighbor grain must be muscovite), state of stress or strain (e.g., a dilating grain boundary), and the proximity of previously nucleated porphyroblasts of the same phase. Our proximity code uses a finite difference formulation of grain boundary diffusion to calculate concentration maps around each nucleated porphyroblast. These maps are summed over the 2D solution space, and a user-defined threshold concentration determines whether or not a site that meets all other criteria for nucleation is viable. These maps therefore act as thermodynamic affinity maps, and control the spacing of nuclei. |