Characterization of a set of specimens of wootz steel. Wootz type identification and texture distribution analysis in cementite

A long term collaboration between CNR (Florence), the ISIS neutron and muon source, and the Wallace Collection (London) was established several year ago to determine the compositional and microstructural characteristics of the so called wootz steel. Wootz steel is a crucible steel that originated in the mid-1st millennium BC in South India, and sword blades made from Indian steel were highly prized and gained a legendary reputation for their quality. Wootz steel exhibits a peculiar pattern at the surface often defined as “watered silk” that originates from the manufacturing method, not fully known nowadays. It is believed to be a crucible steels which have been very slowly cooled to give dendrites of cementite and then carefully forged so that the dendrites are broken up and enabled to form a pattern. A set of 12 cut blade fragments from different swords were cut by conservators of the Nizam Armoury and shipped to the Wallace Collection conservation department for analysis purpose. We intend to perform diffraction measurements on the whole volume of the specimens. Once identified genuine wootz blades, based on the microstructure and the crystalline phases present, we intend to mount them on the goniometer and measure the cementite profile for several sample orientation in order to cover a wide solid angle range and check the relative intensity variation of the sensitive cementite peaks to gain insight about cementite anisotropy and texture.