Crystallization and Deformation

Crystallization and deformation are two processes that can occur simultaneously or sequentially in a material. The relationship between these processes depends on various factors, including the type of material, the temperature and pressure conditions, and the deformation rate.

In some cases, deformation can trigger crystallization or recrystallization in a material. For example, when a metal is deformed, the dislocations created by the deformation can provide nucleation sites for the formation of new grains during recrystallization. This process can lead to the formation of a fine-grained microstructure with improved mechanical properties.

On the other hand, crystallization can also influence the deformation behavior of a material. When a material undergoes solid-state phase transformation during crystallization, its mechanical properties may change significantly. For example, the formation of new crystalline phases with different crystal structures can affect the material's strength, ductility, and hardness.

In some cases, crystallization and deformation can occur simultaneously, leading to complex microstructural evolution in the material. For instance, during the deformation of a metallic glass, the material may undergo in situ crystallization, resulting in the formation of a composite microstructure with both crystalline and amorphous phases.

Overall, the relationship between crystallization and deformation is complex and depends on the specific material and process conditions. However, these two processes can interact and influence each other, leading to significant changes in the material's microstructure and properties.

Pre-Kinematic Crystals:

a. Bent crystals with Undulose extinction

b. Foliation wrapped around a porphyroblast

c. Pressure shadow or fringe

d. Kink bands or folds

e. Microboudinage

f. Deformation twins

Post-Kinematic Crystals:

a. Helicitic folds 

b. Randomly oriented crystals 

c. Polygonal arcs 

d. Chiastolite 

e. Late, inclusion-free rim on a poikiloblast 

f. Random aggregate pseudomorph

Syn-Kinematic Crystals:

(p.s.: Snowball garnet is an example of syn-kinematic crystal.)

Regards, GeoKhan.