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Ancient Swords Made of Carbon Nanotubes
brian0918 writes "Nature reports that researchers at Dresden University believe that sabres from Damascus dating back to 900 AD were formed with help from carbon nanotubes. From the article: 'Sabres from Damascus are made from a type of steel called wootz. But the secret of the swords' manufacture was lost in the eighteenth century.' At high temperatures, impurities in the metal 'could have catalyzed the growth of nanotubes from carbon in the burning wood and leaves used to make the wootz, Paufler suggests. These tubes could then have filled with cementite to produce the wires in the patterned blades, he says.'"
... I've heard so far.
From my understanding the steel was hammered into very very thin sheets- of approximate shape- and then bundled. 30 to 50 of these sheets were then dipped in an carbon-iron fluxed solution at high temperature which was then 'wicked' between the plates by capillary action. Cooled and drop forged by any number of techinques the steel was work hardened and quenched, and provided the best of both world- steel's strength and hardness (sharpness), and the raw iron's fibrous flexibility.
As you know raw iron (no carbon) has packed fibres- you can see them as they rust away- but I have no idea if the fibres are that small...
Anyway... interesting theory.
Sorry about that...
You're special forces then? That's great! I just love your olympics!
Almost every post on slashdot has an overlord joke with a +5 Funny rating. I'm waiting for the day when its not funny any more...
I'm waiting for the day when its not funny any more...
You missed it already. See, it gets not-funny after awhile, and then using it becomes the joke itself and so it is made funny again, only to eventually be over-used and become not funny again. Repeat until the sun goes nova.
>> simple - the slashdot mod system is broken, funny posts get no positive karma.
> That's not a bug, it's a feature.
The way it is implimented, it is a bug.
It has only happend to me once, and only by 1 point, but it is annoying to lose Karma for a post that has a flat or net positive moderation.
+Funny should only be zeroed to the degree that the final score is the same as the starting score.
If you want to give someone Karma and the post doesn't fit into the Insightful or Interesting category, use +1 Underrated.
And if you want to unjustifiably mod someone down because you disagree with them, and not have the moderation reviewed in metamoderation, use -1 Overrated.
Which is probably not what it was intended for.
Apology to Ubuntu forum.
Jokes apart, there is considerable research that has gone into Wootz steel produced in India, and its special properties (reported in the Nature story). My colleague, Prof. Ranganathan (in collaboration with archeometallurgy researcher Dr. Sharada Srinivasan) has written a short article as well as a book (a pre-publication version is available for free: text and figures).
Coming back to the story about the German researcher's suggestion (speculation?) that carbon nanotubes might have been present in Damascus steels, count me among the skeptics. The presence of nano-scale microstructures is a puzzle that was solved quite sometime ago: they are created when hot and cold steel is bashed repeatedly for producing swords. The nanoscale structure is also the reason for its ultra high strength. The presence of nanowires of carbon rich cementite is thus not a 'new' finding.
Finally, to my knowledge, carbon nanotubes have been made only under extremely special circumstances (which also explains why their mass production -- for use, for example, in steels for ship-building -- is still a dream). It's extremely unlikely that the 'ordinary' atmosphere under which Wootz was made would have yielded nanotubes.
Bottomline: Do we need carbon nanotubes to really explain why Damascus swords made with Wootz steel are so special? Use Occam's razor (or, for that matter, the Damascus swords themselves).