Bronze Age Caucasian metalwork: Alloy choice and combination

The chemical composition and microstructure of eleven Bronze Age Caucasian daggers from North Ossetia-Alana, Russia were studied in order to establish a baseline for metallurgy and alloy production in the region. They have been housed in the Natural History Museum, Vienna since the 1880′s. The assemblage comprises arsenical bronzes characterized by high concentrations of arsenic (2-10 wt%), tin bronzes with high tin (10-17 wt%), and several ternary Cu-As-Sn dagger blades. The chemical composition of the dagger blades was analysed with EDXS and XRF. Furthermore, metallographic analyses and lead isotope analyses were carried out. Two of the arsenical bronze blades showed extreme γ-phase segregation along their surfaces and grain boundaries. Two tin-bronze dagger blades, containing high amounts of eutectoid, prevented the measurements of the hardness of the eutectoid. One dagger combined a tin bronze blade and arsenical bronze hilt. Lead isotope analyses of selected daggers indicate a close relation to copper ore sources in the Greater Caucasus and Armenia.