Structure of several historic blades at nanoscale



Comparison of the structure of ancient Damascene steel blades at nanoscale with more recent ones – all made using crucible (wootz) technology and exhibiting ultra-high carbon content – showed for the first time a common feature. Despite different microstructures, colonies of wire- and tube-like particles with diameters of 40-50 nm have been observed with the aid of high-resolution transmission electron microscopy. Crystalline Fe3C is the main phase forming those particles covered in numerous cases by a tube-like layer. These tubes were also found in an empty or partly – covered filled variant. To assess the strengthening capacity of cementite various models were compared. Dispersion strengthening seems the most efficient. Cutting edge qualities may be related to surface corrugations due to nanoparticles. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)