Why are there more grain boundaries after annealing?

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The discussion clarifies that during the annealing process, specifically after recrystallization, the formation of new "strain-free" grains leads to an increase in grain boundaries. This phenomenon is confirmed by the Hall-Petch relationship, which indicates that smaller grains enhance strength while also contributing to ductility. The annealing process aims to reduce internal stress and dislocation density, ultimately making materials softer and more workable. However, the spontaneous growth of grains to minimize grain boundary energy can result in a higher number of grain boundaries initially, which is a critical aspect of understanding material properties post-annealing.

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Metallurgists, materials scientists, and engineers involved in material processing and optimization will benefit from this discussion, particularly those focused on the effects of annealing on grain structure and mechanical properties.

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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