I've seen often in TEM micrography grains within many crystallites, I am wondering what is the difference between the boundary between the crystallites of the same grain to the grain boundary. I would like to understand it in nanoscale.
Thank you!
João.
Dear Joao
By default,boundaries between either crystallites or between grains are dislocated regions,i.e.dislocation lines. So,boundaries between crystallities are discrete dislocation lines.In contrast,boundaries between grains are a bundle of dislocation lines.
The grain consists of a single material, but may be crystalline, or polycrystalline: crystalline size =< grain size
Dear Khaled J. Habib
Thank you for your answer!
This question surged to me when i was thinking about sintering mechanisms in materials which the grain contains multiple crystallites, I imagine that the surface between crystallites should be lower energetic than the grain boundary
I wish you all a happy holiday season with peace in mine, harmony with the surrounding, and progress in life for the best of man kinds.
Thank you I wish you the same! Lets hope for a better year in 2021
Dear Joao Vitor Campos, crystallites are also known as subgrains and their boundaries as subgrain boundaries. Maybe this keyword would be easier to search for them. These are often low-angle grain boundaries made of a network of dislocations. The smaller the angle between two subgrains (or grains) the larger the distance between the dislocations and the lower the energy of that boundary. It is fascinating how the physical property of a grain boundary is different from one another just by slight changes in misorientation angle; They can even have their own phase diagrams just like a bulk phase do!
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