Small-angle grain boundaries

Planar defects surfaces, grain boundaries, small-angle grain boundaries, cell walls, planar stacking faults, antiphase domain walls, shear structures, segregation of impurity atoms to interfaces... 

As remarked in the previous section, single crystals are not perfect but are built of domains of material that are slightly mismatched. The interfaces between these regions are called low-angle or small-angle grain boundaries. These boundaries consist of an array of dislocations arranged so as to remove the misfit between the... 

Tilt boundaries occur if the axis of rotation between the two grains is located in the boundary (interface). In contrast, if the axis of rotation is perpendicular to the boundary, the boundary is called a twist boundary and consists of a collection of screw dislocations (Fig. 3-6b). An equation similar to Eqn. (3.14) holds for twist (and mixed) boundaries. Since dislocation theory is well understood, it is possible to quantitatively treat small-angle grain boundaries [J.P. Hirth, J. Lothe (1982)]. 

Small-Angle Grain Boundaries. As described in Appendix B, these semicoherent boundaries are composed of arrays of discretely spaced lattice dislocations. For... 

The example in Fig. 13.4 is an extension of the model for the motion of a small-angle boundary by the glide and climb of interfacial dislocations (Fig. 13.3). Figure 13.4 presents an expanded view of the internal surfaces of the two crystals that face each other across a large-angle grain boundary. Crystal dislocations have... 

Homophase crystal/crystal interfaces are often called grain boundaries. It is customary to classify such boundaries as either small-angle grain boundaries or large-angle grain boundaries. 

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