Partial dislocations Frank

The partial dislocations described in copper and similar materials are not the only ones that can be described, and a number of other types are well known, including Frank partial dislocations, which mediate in a different slip process. 

FIGURE 2 HREM image of partial dislocations and their schematic maps found in the low temperature GaN layer near the interface (a) interstitial Frank loop (the position of the extra half plane is indicated by arrows in the image) (b) isolated Frank partial dislocation (c) reaction between a dissociated edge dislocation and Shockley partial that is displaced by one basal plane (d) dislocation notation for hexagonal crystal used in (a) - (c). (From [3].)... 

Figure 54. High-resolulion image of a fragment of a C > molecular crystal bright dots represent rows of C ) molecules Note the presence of a stepped intrinsic stacking fault (in S). Also a Frank-type partial dislocation and its associated stacking fault...

The density of partial dislocations allows us also to estimate that the density of Ii-type BSFs is one order of magnitude larger than the density of l2-type faults. However, occasionally it is possible that two Ii faults with different Burgers vectors meet each other, resulting in the appearance of one Shockley partial dislocation instead of two Frank-Shocldey dislocations. This special case is illustrated in Figure 10.8. 

Figure 11.11 Polar plots of the hydrostatic pressure field of a 1 /5[2-203] Frank-Shocldey partial dislocation in a-plane GaN (a) assuming the isotropic case, (b) taking anisotropy into account (cf Color PlateXXXIII).

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