Mitja Petrič

Podzemelj in Bela Krajina region have long been recognised as one of the key and best-researched Iron Age centres of the Dolenjska Hallstatt culture. The recently excavated large cemetery at Pezdirčeva njiva, situated on the north-western slope beneath the hillfort on Kučar, opens a new chapter in the study of this centre and the wider Dolenjska region. Burials at the site begin only in the 5th century BCE and continue uninterrupted until the early 1st century BCE. This monograph provides the first comprehensive publication of modern excavations of graves belonging to the Vinica cultural sphere, which until now had not been systematically analysed. The volume brings together the results of several years of fieldwork directed by Otmar Kovač and the author, and presents detailed documentation of more than 180 graves with rich assemblages of grave goods. The finds are illustrated on 85 plates, and a large-scale plan of the central part of the cemetery is included as an appendix. Analyses of funerary practices, costume, weaponry, pottery, and jewellery are complemented by a wide array of scientific studies assembled in Chapter 10. The monograph incorporates the results of pedological and geoarchaeological research (A. Prijatelj, H. Grčman, R. Turniški) and conservation–archaeometallurgical examinations of non-ceramic finds (N. Nemeček, M. Petrič, P. Fajfar, B. Šetina Batič, M. Nečemer). Additional contributions address textile remains (M. Gleba), archaeobotanical samples (T. Tolar), lithic finds (R. Brajkovič), and amber (M. Golec, Z. Golec Mírová, L. Kučera, J. Martínek). A particular strength of the monograph lies in its cultural and chronological synthesis, which situates Pezdirčeva njiva within the broader development of the Iron Age centre at Podzemelj and clarifies the structural and temporal differences between Late Hallstatt and Vinica-period graves. This comprehensive and interdisciplinary work significantly advances our understanding of settlement dynamics in Bela Krajina, from Podzemelj to Vinica, and provides new insights into cultural processes unfolding along the southeastern Alpine region during the Early and Late Iron Age.

Due to the specific application of aluminum–magnesium–lithium (Al-Mg-Li) alloys in the transportation industry, it is necessary to consider the influence of microstructure development on material degradation under severe environmental conditions. This degradation was simulated according to the standard test method ASTM G34-01 (2018) on a newly designed and synthesized Al-2.1Mg-1.92Li alloy in the as-cast condition. The degradation susceptibility of the alloy was estimated by measuring the changes in the sample mass and microhardness, and the pH and chemical composition of the environment with respect to the exposure time. The influence of the microstructure constituents on the degradation of the alloy was determined using metallographic analysis of the exposed surface and cross-section of the samples after testing. During the degradation, dealloying of the α_Al matrix through Li, Mg and Al component dissolution resulted in a decrease in the mass of the samples, an increase in the pH of the environment and changes in its chemical composition. This observation was also confirmed by the results of the metallographic analysis. The degradation involved the formation of cavities around the Al₈Mg₅ (β) and Al₂LiMg (T) intermetallic phases through an anodic dissolution mechanism. The increase in microhardness values after exposure indicated an increase in the stress around the degradation front due to the wedge effect of the degradation products. The results of the investigation support the potential application of the synthesized Al-2.1Mg-1.92Li alloy under the severe environmental conditions defined by the ASTM G34-01 (2018) standard.

The introduction of lithium (Li) in AlSi7Mg alloys has significant implications for their mechanical properties and phase composition. This study investigates the effect of lithium on the phases present in an AlSi7MgLi alloy with the chemical composition of 7% Silicon, 0.36% Magnesium, and 0.80 Lithium using Thermo-Calc software with calphad methodology. Thermo-Calc, a powerful computational tool for thermodynamic and phase equilibrium analysis, allows for precise simulation of microstructural evolution and phase transformations. This research provides a detailed thermodynamic assessment of the specified alloy composition, focusing on the stability and distribution of phases such as primary silicon, magnesium silicide, and lithium-containing phases. The objective is to understand how lithium affects the phase behaviour and properties of the alloy, guiding the development of optimized compositions for enhanced performance. The results from Thermo-Calc simulations will be compared with available empirical and theoretical data to validate the predictions. This study highlights the importance of computational tools in advancing materials science, enabling precise phase predictions and offering insights into the role of lithium in aluminium alloys.

The production of high quality ductile cast iron requires different and complex inoculants. Besides iron and silicon, they also contain alloying elements such as zirconium, strontium, barium, calcium and rare earth metals. The addition of these elements reduces carbide solidification and increases the number of eutectic cells, which improves the quality of the cast iron produced. This study investigates the process of incipient melting of a complex barium inoculant and its effects on graphite nucleation. In the study, the sample was prepared by introducing the inoculant grain into the melt of the ductile iron. The region between the inoculant grain and the less inoculated matrix was examined metallographically using light and scanning electron microscopy. We used energy dispersion spectroscopy to determine the phases in the microstructure formed. It was found that graphite particles can already nucleate and grow in solid particles when the inoculant is still dissolving and also from the melt where the Ba and Ca concentrations are high and form BaO·CaO phases that serve as nuclei for graphite growth.

Recycling is now, more than ever, an important part of any foundry process due to the high cost of energy. The basis of the work presented here is a study of the addition of foundry scrap returns to the melt in order to reduce material and energy costs. The most important issue in such a process is the quality of both the prepared melt and final product. In this work, scrap returns were added to the AlSi9Cu3 base alloy in different proportions. Chemical composition was monitored, the solidification path was predicted by CALPHAD calculations and monitored by thermal analysis, and the formed microstructure was studied. The mechanical properties were also determined. The results showed that as the amount of scrap returns increased, elements such as Fe, Ni, Pb, Sr, etc. were more built up and elements such as Mg, Mn, Cr, etc. were decreased due to oxidation. The different chemical composition led to a reduced Mn:Fe ratio, resulting in the formation of needle-like Fe-rich phases and a decrease in mechanical properties.

The objective of grain refining is to reduce the size of the primary solidified crystal grains in aluminum alloys, thereby eliminating large columnar grains. Excellent grain refining results can be achieved only when the grain refining agent is of excellent quality, i.e., the number of Al₃Ti and TiB₂ particles must be appropriate, the shape and size distribution of the particles must be suitable, the Ti/B ratio must be appropriate, and so on. To evaluate the quality of grain refiners, the electric resistivity was measured on four different grain refiners. The obtained results were supported by differential scanning calorimetry analyses and microstructure analyses. It was found that the quality of a grain refiner can be assessed by measurements of electrical resistance. The lowest electrical resistivity was measured for grain refiner B (Al-3Ti-1B), which had the lowest impurity content and the most suitable number and size distribution of TiB₂ and Al₃Ti particles, as well as the most optimal Ti/B ratio, namely, 3.6. A larger number and size of TiB₂ and Al₃Ti particles, as well as elements such as Fe and Si, and also inclusions, which were also confirmed by DSC analyses, cause a higher electrical resistivity due to a stronger scattering of electrons through the matrix.

As a major impurity element in aluminium-lithium (Al-Li) alloys, iron (Fe) reduces formability, fracture toughness, and fatigue resistance by solidifying into Al6Fe and Al3Fe particles. The research was performed in order to estimate the influence of Fe impurities on the compression behaviour of Al-2.24Mg-2.09Li alloy. The investigation was performed on the samples in as cast and solution hardened condition. The solution hardening was applied to improve the mechanical properties by dissolving intermetallic particles and enriching ?Al matrix with Mg. However, the higher strength properties and temperature increase during the compression testing were observed in as cast condition. Microstructural investigation revealed significant differences in microstructure changes between the samples in as cast and solution hardened condition. In as cast sample the barrelling effect led to the unequal deformation and surface texture development. The eutectic Al3Fe particles located in the ?Al interdendritic areas did not significantly impact microstructure changes. Although the solution hardening led to enrichment of ?Al matrix with Mg and Fe, the Al3Fe particles were not dissolved. The coarse morphology of Al3Fe particles and location at the grain boundaries of ?Al grains contributed to low energy intergranular fracture. The fracture nucleation and propagation across the grain boundaries resulted in lower strength values.