COMPARATIVE ASSESSMENT OF Al-Si ALLOY GASSING DEGREE WITH THE APPLICATION OF THE ‘FIRST BUBBLE’ AND ‘SOLIDIFICATION UNDER DECREASED PRESSURE’ METHODS

All aluminum alloys in a liquid state are characterised by easy oxidation and absorption of hydrogen from the surroundings (which are the main reasons for casting defects). The amount of hydrogen adsorbed by a liquid alloy depends mainly on temperature and melting time. The performed investigations were aimed at comparing two known methods of measuring a metal gassing degree; the first bubble method and sample solidification under decreased pressure. Liquid metal melting and holding processes were performed under different conditions that caused variability of its gassing degree, resulting in a variability of purity and quality of the liquid metal. The investigations were carried out with using the hypoeutectic aluminum-silica AK7 alloy

ARCHAEOLOGICAL REMAINS OF THE COPPER METALLURGY IN LOWER SILESIA

Many traces of copper metallurgy, such as slag and other copper melts, can be found in the area of Lower Silesia. The research programme, which assesses the exact location and detailed inventory of the sites connected with mining and copper smelting in the area of three historical regions of its exploitation, as well as testing of the collected material is implemented by the Copper Museum in Legnica, in collaboration with the Faculty of Foundry, at the University of Science and Technology. The tested material mainly consists of copper slag with different content of copper melts, being a semi product. The copper metallurgy remains, discovered during the research, undergo specialistic analyses, which will help better characterise the findings as well as contribute to documenting metallurgical processes in the historical bloomeries in Lower Silesia, and moreover to prepare further research in this field.  The material coming from the area of Miedzianka, being the oldest and the longest working exploitation centre of copper ores and pollymetalic ores, is of special significance for the research. Mining activity in the area of Miedzianka took place as early as the beginning of the 14th century, the first record from 1311 (Cuprifodina in montubus) is the oldest information concerning copper mining in Poland

THE INFLUENCE OF SELECTED ALLOYING ELEMENTS ON THE MICROSTRUCTURE, SELECTED MECHANICAL AND TECHNOLOGICAL PROPERTIES OF BRASSES

The research aimed at assessing the influence of alloying elements, such as aluminium, silicon, nickel as well as lead and bismuth on the chosen alloys of Cu-Zn. Microstructures were examined with the help of optical and scanning microscopy with X-ray microanalysis. The properties of the received alloys were determined with regard to changes in the chosen mechanical parameters, namely  Rm, A5, HB, also, machinability changes were assessed as well as proclivity to hot  fracturing  of Cu-Zn alloys with additives of lead and bismuth. The results indicate the possibility of obtaining, within the alloys analysed, very high mechanical properties: Rm up to 700 MPa, hardness within the range of 130 – 180 HB and A5 from 3 to 30 %. Also, in the case of the researched alloys, the machining and hot fracturing results  look promising

Dwie bransolety ze starszego okresu epoki brązu z kujawskiej części Torunia i Brudzynia na Pałukach w świetle badań archeologicznych i archeometalurgicznych

The article presents two metal bracelets found separately but both associated with the manufacturing phase of the early Bronze Age. The lack of data on the original contexts for the finding of both features significantly limits the scope of their cultural interpretation. Therefore, the features might have come from grave goods, treasures, or they could simply have been lost.The artefact found in Toruń (Kujawy part) is from the artillery training area, although it shows analogies in its manufacturing style to features representing the Tumulus culture (proto-Lusatian); it was in fact found in a settlement of the Trzciniec culture, where such funerary artefacts are only sporadically listed as part of metal treasure hoards. On the other hand, the feature found in Brudzyń, in the district of Żnin, suggests a fairly large number of close similarities with the funerary treasures and grave goods found in the Kujawy, Wielkopolska (Greater Poland) and Śląsk (Silesia) regions. The feature was found in the zone where the influences of the Tumulus culture and the Trzciniec culture once overlapped. The results of archaeo-metallurgical expert appraisal indicate that both features represent body ornamentation but can be associated with separate  metallurgical traditions. While there is no doubt that the bracelet from Brudzyń is a bronze product made in a workshop following the south-western style of Tumulus culture, the feature from Toruń might be an example of a local (“Trzciniec”) product, though having the aesthetic features characteristic of Tumulus metal artwork. Based on the results of the archaeo-metallurgical analysis for the artefact from Brudzyń, a virtual model of the process of pouring metal into a casting mould was produced.W artykule zaprezentowano dwie luźno znalezione bransolety metalowe, obie łączone z fazą wytwórczości starszego okresu epoki brązu. Artefakt z Torunia, mimo, że znajduje analogie w wytwórczości kultury mogiłowej, to jednak został znaleziony w przestrzeni środowiska osadniczego kultury trzcinieckiej, w którym tego rodzaju ozdoby południowo-zachodniej proweniencji notowane są sporadycznie. Z kolei wyrób z Brudzynia, znaleziony w strefie zazębiającego się osadnictwa kultur mogiłowej i trzcinieckiej, to okaz mający bliskie i dość liczne analogie w skarbach i wyposażeniu grobów Kujaw, Wielkopolski i Śląska. Wyniki ekspertyzy archeometalurgicznej, wskazują, że prezentowane okazy można wiązać z technologicznie różnymi tradycjami wytwórczości brązowniczej. O ile raczej nie ma wątpliwości, że bransoleta z Brudzynia jest kolejnym wyrobem powstałym w warsztacie „mogiłowym”, o tyle ta z Torunia może być przykładem lokalnego („trzcinieckiego”) produktu mającego cechy stylistyki mogiłowej

COMPUTER MODELING FOR THE VISUALIZATION AND GEOMETRIC RECONSTRUCTION OF ARTEFACTS FROM THE CASTING WORKSHOP IN GRZYBIANY

The casting workshop in Grzybiany is one of the most important archaeological sites in regards to casting technology from the Bronze and Early Iron Ages. During the “Grzybiany. Osada nadjeziorna z epoki brązu i żelaza” [Grzybiany. Lakeside settlement from the Bronze and Early Iron Ages] research, the structure of casting moulds was analyzed as well as the chemical composition and microstructure of one of the more-interesting metal artefacts found within the workshop. Basedon this, geometric visualization was performed with the help of computer-modeling methods. For scientific, experimental, and educational purposes, reconstruction of a zoomorphic pendant was performed using the lost-wax method. Wax models injected into a matrix were used, along with fired ceramic (gypsum) moulds and a specially prepared modeling alloy that corresponds to the original material. In this way, a true replica of the original was obtained: technologically, structurally and chemically.Studies of production technology of the casting workshop dated back to the Bronze and Early Iron Age help to increase the knowledge of the mould-preparing technology and the alloys used. Modern tools and computer programs aid in the research of old technologies and help disseminatethe results

Influence of batch structure on cluster computing performance – complex systems approach

This work presents the problem of clusters computing performance optimization. An assessment of the impact of computing architecture, applications, and communications equipment on the system performance was done. Processing bottlenecks were identified, showing that in order to obtain an optimum usage of computational structure the system should be treated as a complex one in which it is impossible to isolate and optimize each element independently

The Effect of Tin on Microstructure and Properties of the Al-10 wt.% Si Alloy

In this paper, the results from studies regarding near-eutectic Al-Si alloys with Sn as an alloying addition are presented. In most Al-Si alloys, tin is regarded as a contaminant; thus, its amount is limited to up to 0.3 wt.%. The few studies that can be found in the literature regarding the behaviour of tin in aluminium alloys suggest the beneficial effect of this element on selected properties. However, these results were obtained for hypereutectic Al-Si alloys or wrought aluminium alloys. In our studies, the influence of tin contents of up to 1.7 wt.% was determined on the AlSi10 alloy. Thermal analysis, measurements of the mechanical properties of the cast and heat-treated alloy, metallographic observations (light microscopy, scanning electron microscopy), and EDS (X-ray energy dispersive spectrometry) measurement allowed us to fully describe the effect of tin on the aluminium alloy. The results of the thermal analysis showed changes in the range of the α-Al solution crystallisation and the α+β eutectic through a decrease in the alloy’s solidification start point and eutectic solidification point. As a result, the elongation of the alloy was more than double in the AlSi10Sn1.7 alloy, with an A5 value of 8.1% and a tensile strength that was above 200 MPa

Analysis of Eneolithic Copper Jewellery Artifacts from Książnice Cemetery in South Poland

This paper presents a metallographic analysis of copper artifacts from an extraordinary Polish cemetery of Lublin-Volhynian culture dated 4000-3800 BC (Wilk in Analecta Archaeologica Ressoviensia, 2014, pp. 209-243). The Książnice necropolis, Busko-Zdrój county located in South Poland, is characterized by an unprecedented collection of prestigious objects made of copper, rare in the Eneolithic period in Poland. The archaeological studies supplemented with materials analyses give knowledge of prehistoric metallurgy and the processing of copper. For the described group of artifacts, non-destructive microscopic studies were performed including chemical analysis by means of X-ray fluorescence and energy-dispersive X-ray spectroscopy using a scanning electron microscope. The mentioned studies allowed for raw material characteristics of this important discovery