Speaker
Dr
Francesco Grazzi
(Consiglio Nazionale Ricerche)
Description
Historical metallurgy is one of the most interesting fields of archaeometry, especially concerning the production and use of steel for arms and armour. It is evident from several analyses performed on steel samples that the production of arms and armour used cutting edge technology of that time so a study of such artefacts can give fundamental details about the technological skill of a specific area or period. In order to correlate similar samples of a specific age or provenance, it is important to build trustworthy classification parameters rather than simply relying on aesthetic features. Neutron imaging techniques allow us to determine the morphology and microstructure of composite steel artifacts thus allowing us to characterize the composition, the quality of the steel, the presence of welds and the thermal treatment during manufacture.
We intend to start a systematic study to characterize the production methods of European swords in Europe from the early Middle Ages to late Renaissance and to 17th century in order to learn about the evolution of the production techniques: the smelting process to produce iron and steel was better understood and so the quality of the steel increased enormously with a substantial change in the composition and in the reduction of the number and size of slag inclusions and structural defects. The thermal treatments and the structure of the blades changed as well according to the requirements of different fighting techniques made possible by a better knowledge of steel metallurgy. All these characteristics directly influence the morphology and phase distribution of the blades and can be easily observed through neutron imaging.
On this purpose we started analyzing three swords of great historical and artistic importance now belonging to the Bayerisches Nationalmuseum with white beam and energy selective methods. The details of the swords are listed here.
- Longsword, produced in Tyrol in the late 15th century, made of steel, enamel, leather. From Ambras Castle, Innsbruck. This sword is generally considered to be one of the most beautiful medieval swords in existence today.
- Hunting sword, produced by Melchart Diefstetter, Munich, c. 1550, made of steel, wood, mother of pearl, bone, leather. From the collections of the House of Wittelsbach. Only the lower part of this sword blade has been sharpened on both sides. It is likely that this 'long knife' was used for hunting.
- Sword, produced in Northern Italy, possibly Milan, c. 1560, made of steel, enamel. From the Kunstkammer of the margraves of Brandenburg-Ansbach. This majestic sword is considered to be one of the most important objects ever to have been produced by an Italian weaponsmith.
White beam tomography allowed to detect the presence and shape of several morphological features in the bulk of the blades as multilayered structures, cracks, defects, and to determine the width and the shape of the martensitic hardened edges. Energy selective analysis allowed us to determine details of the steel composition and microstructure as well as mapping the different low and high carbon areas.
Primary authors
Dr
Burkhard Schillinger
(Heinz Maier-Leibnitz Zentrum (FRM II))
Dr
Francesco Grazzi
(Consiglio Nazionale Ricerche)
Co-authors
Dr
Alan Williams
(The Wallace Collection)
Dr
Dominik Bausenwein
(Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany)
Dr
Joachim Kreutner
(Bayerisches Nationalmuseum, Munich, Germany)
Dr
Raphael Beuing
(Bayerisches Nationalmuseum, Munich, Germany)
