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Rivkin · 8th October 2006, 07:31 PM

I am by far no specialist, and know absolutely 0 about the field, but I would see it this way:

Imagine that you have a metall at a very high temperature. Atoms move randomly with large amplitudes. Now we introduce a defect - a few atoms are moved away from the equilibrium configuration. Because of random motion the rest of the atoms is likely to adjust to the dislocation - kind of like water does not fall into pieces if you stir it - randomly moving molecus fill the empty space. So is the metall it is plastic - it is actually softer than at small temperatures, but more crack resistant. Now at low temperatures if you move an atom so far away it effectively looses contact with one of its neighbours (the lattice "breaks"), the neighboring atoms can not readjust to maintain the stability, the crack forms and propagates in the material (again, the material can not adjust).

This process obviously depends on how much energy one has to spent to adjust/change the configuration of atoms, so I would expect the "brittleness" being given by energy structure calculations. It is going to greatly depend on the material and its composition, it is quite possible that wootz was more brittle than other steels, however I think it especially relates to the wootz that Biruni was talking about, not some other wootz - I would expect a significant variations depending both on chemistry and on geometry of the wootz (since wootz is essentially two types of lattices in one material).

8th October 2006, 07:31 PM	#5
Rivkin Member Join Date: Dec 2004 Posts: 655	I am by far no specialist, and know absolutely 0 about the field, but I would see it this way: Imagine that you have a metall at a very high temperature. Atoms move randomly with large amplitudes. Now we introduce a defect - a few atoms are moved away from the equilibrium configuration. Because of random motion the rest of the atoms is likely to adjust to the dislocation - kind of like water does not fall into pieces if you stir it - randomly moving molecus fill the empty space. So is the metall it is plastic - it is actually softer than at small temperatures, but more crack resistant. Now at low temperatures if you move an atom so far away it effectively looses contact with one of its neighbours (the lattice "breaks"), the neighboring atoms can not readjust to maintain the stability, the crack forms and propagates in the material (again, the material can not adjust). This process obviously depends on how much energy one has to spent to adjust/change the configuration of atoms, so I would expect the "brittleness" being given by energy structure calculations. It is going to greatly depend on the material and its composition, it is quite possible that wootz was more brittle than other steels, however I think it especially relates to the wootz that Biruni was talking about, not some other wootz - I would expect a significant variations depending both on chemistry and on geometry of the wootz (since wootz is essentially two types of lattices in one material).