After the annihilation of opposite sign dislocations, remaining dislocations start spreading to reduce the effect of internal stresses. This process of arranging of leftover dislocations is termed polygonization where edge dislocation combines to create tilt boundaries while screw dislocations combine to create twist boundaries.
Etching methods are efficient in identifying the polygonization process. After polishing the surface, etching is carried out. Consecutive etch pits on polished surface identify sub-boundaries like tilt and twist boundaries. Each pit basically gives an idea of dislocation presence.