These are the 3 major types of twinning in metals. I would like to know if there is any difference in terms of interface/boundary energy of these 3 types if I hypothetically have coherent twin boundaries of all these twins in different samples, in a low SFE material like Silver. In one sample, coherent deformation twins and other annealing twin and so on.
Rohit, in principle there should be no difference, but one would start by saying that each of these defects have a different origin. Deformation twins, for example, occur simultaneously (mostly) with dislocation slip, so the coherent interface may be distorted (curved), this would mean that the interface contains defects and hence, has a different surface tension compared, for example, with the flat interface of a recrystallization twin. So, answering your question, in principle there should be no difference between the coherent interface in deformation and recrystallization twins, but they may differ in the praxis due to the twin growth mechanism, which could produce more defects in one or the other type. Hope this helped.
Rohit, in principle there should be no difference, but one would start by saying that each of these defects have a different origin. Deformation twins, for example, occur simultaneously (mostly) with dislocation slip, so the coherent interface may be distorted (curved), this would mean that the interface contains defects and hence, has a different surface tension compared, for example, with the flat interface of a recrystallization twin. So, answering your question, in principle there should be no difference between the coherent interface in deformation and recrystallization twins, but they may differ in the praxis due to the twin growth mechanism, which could produce more defects in one or the other type. Hope this helped.
Deformation twins are generally lens shaped, while annealing twins appear as parallel lines.
Yes, this is due to the residual stresses that develop during twin growth in deformation twins, but the interface should be the same.
Thanks for the informative replies. Does this mean that deformation twins are generally incoherent. Since Deformation twins are generally lens shaped and should therefore the shape should be accommodated by dislocations. Is this correct?
No Rohit, the interface (habit plane) of deformation twins is as coherent as the one for recrystallization twins, the only difference is in the shape, which means that the habit plane of a deformation twin should contain more defects (like interfacial dislocations, ledges and so on) compared to a recrystallization twin (in the coherent interface, of course, a recrystallization twin has also an incoherent interface, when it ends inside a grain). Both are, per definition sigma=3 grain boundaries. The presence of defects in a interface does not mean it looses coherency, the situation is analogous of a crystal, a dislocation is a perturbation of the local order of the lattice, but a crystal does not looses its crystallinity (not even its simetry group) just because it has a dislocation inside.
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