Respuesta :
Answer / Explanation:
To properly answer this question, let us define what a grain boundary is:
A grain boundary is the interface between multiple grains or crystals in a poly-crystalline material. They could also be refereed to as defects in the crystal structure and tend to decrease the electrical and thermal conductivity of structures.
Now, if we refer back to the question asked,
(a) The surface energy is grater than the grain boundary energy because surface atom have fewer bonds than atom along a grain boundary.
Consequentially, the lower the number of bonds formed, the higher the energy
(b) A higher angle grain boundary has higher misalignment and hence greater disruption of bonds (lesser number of bonds) than a small angle grain boundary. Therefore, a high angle grain boundary has higher energy.
(a) Yes, we expect the surface energy to be greater than, the same as, or less than the grain boundary energy.
(b) yes, the grain boundary energy of a small-angle grain boundary is less than that for a high-angle one.
What Does GB (Grain Boundary) Stand For?
In a polycrystalline material, a grain boundary (GB) is the point where two grains, or crystallites, meet. Grain boundaries are flaws in the crystal structure that reduce the material's electrical and thermal conductivity.
A grain boundary is a general planar defect in a polycrystalline material that divides areas of varied crystallographic orientation.
When a solid crystallizes, grain boundaries are frequently the consequence of uneven development. The grain size ranges from 1 mm to 1 m.
Reasons for the statement given in the problem.
(a) Because surface atoms have fewer links than atoms at a grain boundary, the surface energy is greater than the grain boundary energy.
As a result, the higher the energy, the lesser the number of bonds created.
(b) A higher angle grain border has more misalignment and, as a result, more bond disruption (fewer bonds) than a smaller angle grain boundary.
As a result, a grain with a high angle.
To learn more about the grain boundary refer to the link;
https://brainly.com/question/24603399
