A thermodynamic criterion is developed to define the finest grain size that can be achieved during phase transformation, as a function of the driving force, interfacial energies and the parent phase grain size. It is found that at large undercoolings below the equilibrium temperature, the grain size achieved in practice is far greater than predicted theoretically. This is because of the heat of...

The applicability of standard lattice percolation models to a random two-dimensional grain structure is explored. A random network based on the triangle lattice is proposed as a more appropriate model, and results in a higher percolation threshold (0.711 compared with 0.653 for the standard hexagonal lattice). The triple junction constraint inherent in grain boundary structures is subsequently ...

The grain shape and orientation distribution of metal sheets at mesoscales are usually irregular, which has an impact on the elastic properties materials. A function (GSF) is constructed to represent grains. expansion coefficient GSF basis Wigner D called coefficient. In this paper, we study influence average constitutive relation orthogonal polycrystalline materials, obtain a new expression ma...

Anisotropic Bi segregation, at surfaces of a Cu polycrystal saturated with Bi at 1223 K, changes the Cu equilibrium shape from a faceted spheroid displaying all orientations to an almost polyhedral shape with missing orientations. Surface cleaning, followed by annealing at !573 K, leads to Bi readsorption from some grain boundary sources. ! 2003 Acta Materialia Inc. Published by Elsevier Ltd. A...

Ice cores through an ice sheet can be regarded as a sample of a unique natural deformation experiment lasting up to a million years. Compared to other geological materials forming the earth‘s crust, the microstructure is directly accessible over the full depth. Controlled sublimation etching of polished ice sections reveals pores, air bubbles, grain boundaries and subgrain boundaries at the sur...

We propose in this article a shape segmentation method for granular structures in 3D based on medial axis. We define a two-step algorithm: the first step rely on a notion of digital flow to obtain a first over-segmentation from medial balls. During a second step, we apply a geometric criterion to obtain a relevant and precise volumetric segmentation. We apply our algorithm to 3D microtomographi...