Question

Explain in detail the difference between the microstructures of a cold worked sample and Recrystallized sample ?

Answer 1

Answer:

A recrystallization process differs mainly from a restoration process (microestructures of a cold worked sample) in that  the first, the microstructure of the final product consists mainly of  high angle borders.

Explanation:

The microstructure of a cold worked material has a high energy stored in dislocations and subgrains. During a heat treatment, this microstructure evolves in order to achieve a more stable state by reducing its energy. The complex microscopic mechanisms that take place during this process have been traditionally encompassed in three categories: restoration, recrystallization and grain growth, which will be discussed later.

These processes generally lead to the total or partial recovery of the original properties of the material (ductility, resistance). They can take place under dynamic conditions, that is, during thermomechanical processing or when the material is subsequently deformed at high temperature, and under static conditions, that is, during a heat treatment after thermomechanical processing.

The term restoration encompasses the following succession of micromechanism: formation of dislocation cells,  annihilation of dislocations within them, formation of subgrains and their growth.

A recrystallization process differs mainly from a restoration process in that in the first one the microstructure of the final product is mainly formed by high-angle borders.