Continuous dynamic recrystallization is common in materials with high stacking-fault energies. It occurs when low angle grain boundaries form and evolve into high angle boundaries, forming new grains in the process. For continuous dynamic recrystallization there is no clear distinction between nucleation and growth phases of the new grains.
Continuous Dynamic Recrystallization has 4 main characteristics:
* As strain increases, stress increases
* As strain increases, subgrain boundary misorientation increases
* As low angle grain boundaries evolve into high angle grain boundaries, the misorientation increases homogeneously
* As deformation increases, crystallite size decreases
There are three main mechanisms of continuous dynamic recrystallization:
First, continuous dynamic recrystallization can occur when low angle grain boundaries are assembled from dislocations formed within the grain. When the material is subjected to continued stress, the misorientation angle increases until the critical angle is achieved, creating a high angle grain boundary. This evolution can be promoted by the pinning of subgrain boundaries.
Second, continuous dynamic recrystallization can occur through subgrain rotation recrystallization; subgrains rotate increasing the misorientation angle. Once the misorientation angle exceeds the critical angle, the former subgrains qualify as independent grains.
Third, continuous dynamic recrystallization can occur due to deformation caused by microshear bands. Subgrains are assembled by dislocations within the grain formed during work hardening. If microshear bands are formed within the grain, the stress they introduce rapidly increases the misorientation of low angle grain boundaries, transforming them into high angle grain boundaries. However, the impact of microshear bands are localized, so this mechanism preferentially impacts regions which deform heterogeneously, such as microshear bands or areas near pre-existing grain boundaries. As recrystallization proceeds, it spreads out from these zones, generating a homogenous, equiaxed microstructure.