high tin bronze

В статье рассмотрены наиболее значимые зарубежные исследования по античным светильникам с конца XIX в. и по настоящее время, в частности труды З. Лешке, О. Бронира, Р. Хауленда и Д. Бейли, а также публикации музейных каталогов, отдельно экземпляров, а также междисциплинарные исследования с применением современных методов. Автор выделяет особенности методологии изучения, анализа и публикаций светильников. Особое внимание уделяется вопросу формирования и изменения систем датирования различных типов светильников / The article presents an overview of the most signifi cant western studies on antique lamps
from the end of the 19th century to the present, in particular the works of Z. Loeschcke, O. Bronier, R. Howland and D. Bailey, as well as publications of museum catalogues, individual specimens, and interdisciplinary studies using modern methods. The author highlights the features of the methodology for studying, analyzing and publishing lamps. Particular attention is paid to the issue of the formation and change of dating systems for various types of lamps.

Since ancient times the use of high-tin bronze alloys (>17 wt.%) has been mainly limited to the production of specific objects such as mirrors and bells. High-tin bronzes can show distinctive colour reflection, as well as mechanical properties and corrosion resistance that clearly distinguish it from the classical bronze composition (with 8-12 wt.% Sn). In the present study samples of archaeological high-tin bronze bells were studied by optical microscopy, SEM-EDS and Raman imaging with the aim of characterising their microstructural long-term corrosion patterns. Results show the presence of high quantities of  phase, when compared to the classical bronze composition, which makes some corrosion structures more visible in these alloys. The corrosion morphologies show selective corrosion of different metal phases along depth of corrosion, which were attributed to different oxygen potentials. This study proposes a classification of four types of corrosion structures occurring in two phase bronzes as a consequence of aeration conditions during burial time and aeration within the corrosion structure.

An important utility parameter of bells, including church bells, is their sound-that depends on geometry of the body, changes in section thickness and material from which they are made. Knowing the geometry of casting and chemical composition of the alloy, it seems that the current state of art allows recreating not only solid, but also acoustic properties of the casting. Hence, the purpose of this work is to make a casting using reverse engineering tools, compare acoustic properties of the newly formed bell with the prototype, and test material for a bell alloy. For the host and casted bell the note and octave are identical, the sound differs only in the number of cents away from the exact note. Compared with the numerical model, the acoustic properties of newly formed bell were found with slight deviations. The reasons for registered differences between the components of the original sound and the copy are seen as differences during melting, pouring and solidification processes of the alloy. Material tests carried out on samples taken from the new bell also showed microporosity of the casting and change in microhardness of the a and eutectoid phase (a + d) along height of the bell cross-section. The chemical composition of bronze also varied along with the change of measuring points at the rib height and the fraction of eutectoid in the alloy structure. Material tests showed a significant influence of cast porosity on its acoustic properties.

High-tin bronze or β-bronze, commonly known as bell metal came into existence as a cast metal since late second millennium BC. The general composition of 23 Sn-Cu holds good reputation as a castable alloy. But it offers enormous difficulty in forging due to its narrow forging range as well as its metastable thermodynamics of incomplete phases prevalent in the Cu-Sn system. Though widely used in castings for manufacturing gongs and bells throughout the world, only few people of the ancient world could achieve the mastery of forging this alloy into thin sheets. Ancient Bengal had been one of those few centres where circular bowls or tumblers or pots of very thin sections were manufactured. Some ethno-archaeological studies were also conducted on Bengal artisans presently engaged in this forging trade.

In the present study, a comprehensive microstructural analysis of the fractured bells of Great Anthony Church of Saint Andrew Skete of Mount Athos, a significant monument of Orthodox tradition and Cultural heritage, was performed. The bronze alloy chemical composition together with metallographic examination, scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy toward the identification of the phases and other micro-constituents and discontinuities present in the internal structure was documented and illustrated in conjunction with the applied bell manufacturing process. Tin bronze alloy was used for bell making, with a chemical composition (up to 18% Sn as a main alloying element) signifying most likely that the bell was produced at the Empire era. The as-cast microstructure primarily consisted of a-dendrites and a ? d interdendritic eutectoid mixture with Pb globules and scattered porosity. Furthermore, electron backscattered diffraction analysis was conducted in order to determine texture properties and obtain crystallographic information regarding the bells' cast structure.

Aluminium bronzes belong to the high-grade constructional materials applied on the put under strongly load pieces of machines, about good sliding, resistant properties on corrosion both in the cast state how and after the thermal processing. It moves to them Cr and Si in the aim of the improvement of their usable proprieties. Additions Mo and/or W were not applied so far in the larger concentration, these elements were introduced to the melts of the copper as the components of modifiers. It was worked out therefore the new kind of bronzes casting including these elements. Make additions to the Cu-Al-Fe-Ni bronze of Si, Cr, Mo and/or W in the rise of these properties makes possible. The investigations of the influence of the wall thickness of the cast on size of crystallites were conducted: the primary phase β and intermetallic phase κ and the width separates of the secondary phase α precipitate at phase boundary. It results from conducted investigations, that in the aluminium bronze BA1055 after simultaneous makes additions Si, Cr, Mo and in the primary phase β it undergoes considerable reducing size. The addition W reduce size of the grain phase β in the thin walls of the cast 3-6 mm, and addition Cr in the range of the thickness of the wall of the cast 3-6 mm it favors to reducing size the phase β, in walls 12-25 mm the growth causes it. The addition Mo does not influence the change of the size of the grain of the β phase significantly. The make addition singly or simultaneously of the Cr, Mo and W to the bronze CuAl10Fe5Ni5Si it influences the decrease of the quantity separates of the phase α on the interface boundary and of width it separates independently from the thickness of the wall of the cast. The simultaneous make addition of the Si, Cr, Mo and W it enlarges the surface of the phase κ Fe , κ Mo. The make addition to the bronze CuAl10Fe5Ni5Si of the Cr, Mo or W the quantity of crystallizing hard phase κ enlarges and the hardness HB of the bronze raises. The make addition singly the Mo or W, if also simultaneous with the addition Cr reduces their make addition it sensibility on the change of the thickness of the wall of the cast (3-25 mm) guaranteeing the possibly small fall the hardness the bronze about 22-28 HB. More far works over new multicomponent aluminium bronzes will be guided in the direction of the identification of the changes of mechanical properties of studied bronzes under the influence of the thermal processing.

High-tin bronze or β-bronze, commonly known as bell metal came into existence as a cast metal since late second millennium BC. The general composition of 23 Sn-Cu holds good reputation as a castable alloy. But it offers enormous difficulty in forging due to its narrow forging range as well as its metastable thermodynamics of incomplete phases prevalent in the Cu-Sn system. Though widely used in castings for manufacturing gongs and bells throughout the world, only few people of the ancient world could achieve the mastery of forging this alloy into thin sheets. Ancient Bengal had been one of those few centres where circular bowls or tumblers or pots of very thin sections were manufactured. Some ethno-archaeological studies were also conducted on Bengal artisans presently engaged in this forging trade.

Few years back some bronze artefacts were recovered by villagers in South 24-Paraganas District of West Bengal during excavation, as chance finds. Two of the artefacts were of bronzes, one Radha and one Krishna, and were in heavily corroded state, needing restoration for display at the museum gallery of Sundarban Anchalik Sangrahasala, Baruipur. Jadavpur University was approached to help in the restoration work and so, laser cleaning was applied to clean the surface of the items. Small fragments of each item were collected to undertake metallurgical characterization for investigation of metal technology. The investigation revealed cast metal technology in hot molds, and, on that basis a reconstructed methoding design for manufacturing the castings has been attempted.

The structural investigations performed and described in this paper are focused on both the segregation phenomenon at the dendrite level, and on the external structure in the equilibrium state. Qualitative and quantitative investigations of the Zn-Al eutectoid alloy (22% Al) structures in equilibrium and non-equilibrium states were considered and studied, revealing that, in this composition, dendritic segregation determines the eutectic transformation. Solidification in non-equilibrium conditions controls both the eutectic transformation and the significant variation of the chemical composition within the dendritic unit, as well as in other constituents. The most important effect of dendritic segregation is on the ratio of the different phases and on their geometry and distribution within the metallic matrix, which determines the material topology. The phenomena involved in such conditions are governed by the structural transformations, which take place during solidification and coo...

High-tin bronze or β-bronze, commonly known as bell metal came into existence as a cast metal since late second millennium BC. The general composition of 23
Sn–Cu holds good reputation as a castable alloy. But it offers enormous difficulty in forging due to its
narrow forging range as well as its metastable thermodynamics of incomplete phases prevalent in the
Cu–Sn system. Though widely used in castings for
manufacturing gongs and bells throughout the world,
only few people of the ancient world could achieve the
mastery of forging this alloy into thin sheets. Ancient
Bengal had been one of those few centres where circular bowls or tumblers or pots of very thin sections
were manufactured. Some ethno-archaeological studies were also conducted on Bengal artisans presently
engaged in this forging trade.

Errors frequently occur in the chronological evaluation of compared complexes dating back to the Early Iron Age from the Cisurals and Western Siberia in terms of dating by comparison with analogues. The evolutionary-typological method can be complemented by the chronological analysis of the stylistic features of artistic casting. Researchers have distinguished a period of intensification of cultural contacts between the Urals and Western Siberia in the early 1st millennium A.D. This reflected in the distribution of a similar type of inventory and several groups of artistic casting. These are the Cherdyn' (ChSG), Ust'–Polui (USG) and Kholmogorsky (KhSG) stylistic groups. The similarity inherent in the casting groups suggests their correspondence to a single chronological period. The KhSG items feature the evidence of a significant influence of metallurgists from the Urals. It is their cultural traditions of the 1st–2nd centuries which reflected in the series of castings. The probable region of the mass production of KhSG items is the southern area of the Middle Transurals. The establishment of a new metallurgical centre in the area could have been stimulated by the fact that in the 1st–3rd centuries the region bordered on trade routes between the Kama Region and Central Asia. The lower dates of distant imports corresponding to the KhSG items provide reliable grounds for the hypothesis that the existing dating of ChSG items and the related complexes is questionable.

The paper presents the obtaining of shape memory alloys, base copper and a diffractometer and microscopic study on some samples. The study was made on CuZnAl samples, obtained by classic casting and educated. The shape memory alloys properties recommend their use for applications in domains as follows electric contacts, robotics, and aeronautics. When choosing the type of alloy used for the manufacture of the component parts of different industrial applications, it must be taken into account fatigue resistance, resistance to shocks and resistance to corrosion. Shape memory alloys are a unique group of alloys with the ability to remember a form even after quite severe plastic deformations. At low temperatures, shape memory alloys can be deformed apparently like other metallic alloys, but this deformation can recover with a relatively modest increase in temperature. 2. The second stage involves storing tension, by the action of external forces, the martensitic state, strong macles. Macroscopic deformation occurs by migration limits macles and increases those variables that are most favorably oriented to the applied voltage.

Some attention in physical metallurgy is devoted to the mechanisms of decomposition of the disordered phases via eutectoid transformation accompanied by the atomic ordering. In case of the non-pearlitic modes of transformation this concerns intermetallic phases of the general description A3B-A3C. The application of intensive deformation like HPT may introduce opposite mechanisms introducing some degree of the metastable disordered phase structure at room temperature. The paper presents results of the phase composition and microstructure studies of the alloys of composition Ni75AlxVy (where x =15, 10, 5 and y =10, 15, 20), which undergo the solid-state eutectoid decomposition at temperature 1281 K, in the equilibrium conditions. The alloys achieved by the cold crucible levitation method were later intensively deformed with the method of high pressure torsion (HPT). The alloys after HPT revealed homogenous, metastable L12 (Ni3Al) structure in place of the eutectoid product L12-D022. The average size of the Sherrer’s coherent diffraction volumes did not exceed 9 nm, suggesting nano-structure of the material. Transmission electron microscopy (TEM) and high resolution electron microscopy (HRTEM) revealed that the micro- and nano- deformation twins were the main feature of the microstructure, dividing volume into cells of the sizes similar to the coherent volumes. The HPT deformation did not influence atomic order. The results are compared with those achieved for the injection cast samples.