V. Traskine

Grain Boundary Wetting Statistic in Zn/Ga System and its Application to Grain Boundary Energy Spectrum Estimation

The grain boundary statistic in zinc polycrystals in contact with saturated Ga(Zn) melt has been studied. The misorientation angle distributions for zinc thin foil and zinc plates were obtained. The influence of the misorientation angle Θ value on the wetting probability p of grain boundaries was observed. The grain boundary energy distribution parameters were obtained by using the p(Θ) relationship. The dihedral angles in triple lines of non-wetted zinc samples were also measured and their distribution was used to obtain the grain boundary energy distribution function. The parameters obtained by two different methods correspond to one other.

Analysis of grain boundary network topology using grain boundary wetting

A statistical method for the experimental study of the grain boundary network topology is proposed. The experimental binary classification of grain boundaries is based on their wetting behavior (wetted and non-wetted grain boundaries). The grain boundary energy distribution is used to describe the intergranular liquid network topology by means of the percolation theory. The model is applied to the experimental study of grain boundary wetting of polycrystalline zinc and aluminum by liquid gallium. Elemental mapping in a scanning electron microscope is used for cluster determination. The experimental observations are in accordance with the theory.

Percolation Properties of Internal Wetted Polycrystals: Effect of Stresses and Material Structure

It is well established from studies of bicrystals that the wetting behavior of grain boundary (GB) depends on the GB crystallography and stress. However, only in several researches of polycrystalline materials properties this boundary-boundary variability is taken into account. In polycrystalline materials the whole network of GB is never completely wetted. The number of wetted boundaries and the topology of their network vary as a function of many factors such as texture, intensity and sign of residual or applied stresses, impurities, content, and specimen size. The role of these factors is not clearly understood yet. This article is devoted to the effect of material structure and stresses on the relative number of wetted GBs and on the connectivity of intergranular liquid in polycrystalline materials. Percolation approach is employed to describe the liquid phase connectivity in internal wetted polycrystals. Some examples are regarded. The relative number of wetted GBs in Zn/Ga system is established on the basis of the distribution of GB orientations and GB wetting statistics. The influence of stresses on the network topology and percolation threshold (the critical concentration of wetted boundaries at which an infinite network appears) value is discussed. The computer modeling is fulfilled to evaluate the threshold as the function of grain shape. The topology of liquid phase inclusions is discussed in terms of critical indexes.