The master's thesis presents the research of a helmet found in the newly discovered cemetery of Pezdirčeva njiva, in Podzemelj. The cemetery dates to the Late Hallstatt period or the Late Iron Age (500–200 years BC). The helmet can be considered one of the most important archaeological finds of recent years in Slovenia, while only about 120 helmets have been found in the world.
The aim of the work was to characterise the microstructure, to analyse in detail the chemical composition of the samples from different parts of the helmet and to identify the intended manufacturing route. In such finds, samples must be taken with great care and in the least conspicuous places possible. The samples were imaged on a scanning electron microscope (SEM) and chemical analysis was carried out by energy dispersive spectroscopy (EDS). Investigations were carried out both in the metallic base area and in the area at the edge where the oxide layer is present. In addition, electron backscatter diffraction (EBSD) was carried out to determine grain orientation and size. In the second part, results of the chemical composition of the helmet particles were used to produce an alloy, which was then hand forged using different protocols. The forged bar samples were imaged using a light microscope.
The results show that the metallic base of the bronze helmet consists of a single phase of copper and tin, with elongated PbS inclusions. The microstructure shows twin boundaries and slip lines, which, together with the inclusions, indicate significant deformation during manufacturing. The oxide layer is uneven and is thicker on the outside, where soil is also present. Comparing the results of the forging with the analysis of the helmet found, it can be concluded that the helmet was made by alternating cold forging and annealing.
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