[8-Ball]

redleader,

As I said, I've not been taught about thermal conduction, though the principles I have outlined will have the same effect on electron mobility. Essentially, there are two extremes.

No defects, good conductivity, crap strength.

Lots of defects, crap conductivity, great strength.

You would not believe how low the dislocation densities are in modern semcionductor wafers.

BillA

annealing can change the workpieces shape, though it doesn't necessarily have to.

Granted some work pieces may have large scale stresses, but the stresses implied with stress relieving are microscopic, as opposed to macroscopic.

The point of annealing is to give diffusion (thermally activated) time to lower the free energy of the system.

Vacancies, defects, dislocations and impurities have free energies associated with them due to their surrounding strees fields. By annealing, the material is rearranged into sub grains with few defects. A large number of dislocations will be anhiliated by collision with a dislocation of the same type (edge or screw) and an opposite burger's vector. (A vector quantity which defines the effect of the dislcocation). A large number of vacancies will diffuse to grain boundaries where they will naturally segregate into locations where atoms would experience high stress fields.

Essentially, annealing is the thermal diffusion of matter/dislocations/vacancies, so as to lower the overall energy.

This allows the material to maintain the current defined shape without the high energy concentrations associated with dislocation locks, twins and so on.

If you like, I will check this with one of my lecturers.

8-ball