Triple junction wetting

The microstructural evidence for Goss grains to grow by the triple junction wetting, as shovm in Figure 11.30, can be found at the growth front of an abnormally... 

However, when HRTEM was employed on the SiC samples, which showed a similar contrast variation across SiC grain boundaries in the SEM, the presence of residual intergranular films was not detected even at the triple junctions. Hence, Kleebe concluded that SEM imaging and Fresnel fringe TEM imaging alone do not enable a safe conclusion to be drawn about interface wetting in ceramic polycrystals. 

Hwang, N.M., Lee, S.B., and Kim, D.-Y. (2001) Abnormal grain growth by solid-state wetting along grain bormdary or triple junction. Scripta Mater, 44, 1153-1160. 

Figure 5.34 presents various situations, from the case of a (amorphous) second phase which wets extremely well (Figs. 5.34f and 5.33c) to its absolute opposite (Fig. 5.34a), the complete separation of the second phase into the triple-grain junction. While the surface tension is accessible from wetting experiments (see Eq. (5.76)), the grain boundary tension can be determined by measuring the grooving angle of the grain boimdary trench (see Fig. 5.35). The relevant relationship follows from...

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