Indian Steel Wootz’ Usage in Damascus Swords
Sabres from Damascus, now in Syria, date back as far as 900 AD. Strong and sharp, they were forged from Indian steel called wootz, reports Nature.
Peter Paufler of the Technical University of Dresden, Germany and colleagues studied samples of a 17th-century sword under an electron microscope and found that wootz has a microstructure of nano-metre-sized tubes, just like carbon nanotubes used in modern technologies for their lightweight strength.
The researchers think that the sophisticated process of forging and annealing the steel formed the nanotubes and the nanowires, and could explain the amazing mechanical properties of the swordsWootz’s ingredients include iron ores from India that contain transition-metal impurities. It was thought that these impurities helped cementite wires to form, but it wasn’t clear how. Paufler thinks carbon nanotubes could be the missing piece of the puzzle.
At high temperatures, the impurities in the Indian ores could have catalysed 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.
