In Sir Walter Scott's book The Talisman, he recreated the scene of October 1192, when Richard Lionheart of England and Saladin the Saracen met to end the Third Crusade (there would be five more after Richard retired to England, depending on how you count your crusades). Scott imagined an arms demonstration between the two men, Richard wielding a good English broadsword and Saladin, a scimitar of Damascus steel, "a curved and narrow blade, which glittered not like the swords of the Franks, but was, on the contrary, of a dull blue colour, marked with ten millions of meandering lines..." This fearsome weapon, at least in Scott's overblown prose, represented the winner in this medieval arms race... or at least a fair match.
Damascus Steel: Understanding the Alchemy
The legendary sword known as the Damascus steel intimidated the European invaders into the 'Holy Lands' of the Islamic civilization throughout the Crusades (AD 1095-1270). Blacksmiths in Europe attempted to match the steel, using the pattern welding technique of alternating layers of steel and iron, folding and twisting the metal during the forging process. (Pattern welding was a technique used by swordmakers from around the world, including Celts of the 6th century BC, Vikings of the 11th century AD and the 13th century Japanese.)
In some cases, the European blacksmiths etched the blade or overlaid the surface of the blade with silver or copper filigree to imitate the characteristic watery lines of the Damascus steel blade. Some scholars credit this search for the Damascus steel process as the origins of modern materials science. But the European blacksmiths never duplicated the solid core Damascus steel, and the secret of its construction was lost even to the Islamic blacksmiths in the mid-18th century.
Wootz Steel and Saracen Blades
What is known today about "true" or "oriental" Damascus steel is that it was made from a raw material called wootz steel. Wootz was an exceptional grade of iron ore steel first made in southern and south central India and Sri Lanka perhaps as early as 300 BC. Wootz was extracted from raw iron ore and formed using a crucible to melt, burn away impurities and add important ingredients, including a high carbon content (nearly 1.5% by weight---wrought iron typically has carbon content around .1%).
The high carbon content is the key--and the achilles heel--in the manufacturing process. High carbon content makes the keen edge and its durability possible; but its presence in the mixture is almost impossible to control. Too little carbon and the resulting stuff is wrought iron, too soft for these purposes; too much and you get cast iron, too brittle. If the process doesn't go right, the steel forms plates of cementite, a phase of iron which is hopelessly fragile. Somehow, Islamic metallurgists were able to control for the inherent fragility and forge the raw material into fighting weapons, an ability that somehow was lost in the mid-18th century.
But the problem is: it doesn't really make any sense that blacksmiths would lose such a useful technology. Since the knowledge of the forgers has been lost many researchers have sought it, and in fact this report is based on their findings over the past decade or more. But in a recent article in Nature, a research team led by Peter Paufler at the University of Dresden report that they may have an idea of the mechanics of how the high carbon steel was created and why it disappeared. That idea lies in that most modern of materials sciences: nanotechnology.