Why are there more grain boundaries after annealing?

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After annealing, the recrystallization process creates new, smaller grains, resulting in an increased number of grain boundaries. This phenomenon can enhance strength due to the Hall-Petch relationship, which states that smaller grains lead to greater strength. However, the overall goal of annealing is to reduce internal stresses and dislocation density, making the material more ductile. The type of annealing, such as full annealing, can lead to grain growth where smaller grains are consumed by larger ones, ultimately increasing ductility. Therefore, while more grain boundaries may initially suggest increased strength, the overall effect of annealing is to improve ductility and processability.
mrhorse09
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I've been confused for a long time and can't figure this out:
In annealing process, after recrystallisation, new "strain-free" grains replaced the strained grains, but it seems there are much more grain boundaries than before the material was annealed? Is this true?
Having more grain boundaries means the materials is stronger but annealing process aims to make the material has less strength and more ductile.

So why is that?
 
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That's true, after recrystallisation, grains will become smaller.and refer to the Hall-Petch relationship,this will make the material has more strength and more ductile.(compared with the material before work hardening)
Annealing process is aimed at make the material softer, so wo can processing it easier
 
The inter stress and the density of dislocation would be decreased after annealing, these are other points affecting the strength and ductile.
 
The grains grow spontaneously to reduce grain boundary energy during anneal.
 
It is depends on what kind of annealing you used. In full annealing, after recrystallization process, it is follow by grains growth, the small grains will be consumed by large grains, then the overall size of grains will be increased, and thus make the steel more ductile, and deformable.
 
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