Dani János - Hajdú Zsigmond - Nagy Emese Gyöngyvér szerk.: MÓMOSZ I. (Debrecen, 2001)

Szabó Géza: Újabb eredmények és módszerek a Kárpát-medence késő bronzkori tárgyainak archaeometallurgiai vizsgálataiban

case of two small pieces of plate. For the roundedend, punched plate stripe (No. 154) polygonal grains show the cast origin, whereas the other plate fragment of irregular form and melt-dented on three sides (No. 168) show some traces of dendritic crystallisation, the most usual form for the prehistoric objects: between the dendrite branches in alpha phase one can find considerable alpha+delta eutectoid isles. /Fig. 1.1./Particularly interesting is the fact, that at the dendritic structures appearing also on the surface, along the boundaries of crystallites one can also observe some tin abundant precipitations. /Fig. 1.2./ This phenomenon is supposedly related to the essentially faster cooling of the surface of pieces in the moulding process as it is demonstrated also by the found edge of the plate, which did not perfectly mould up to the form. For the articles where the polished surfaces show unambiguously the casting, one single case of relatively fast cooling could be identified. On the cut surface of ring (No. Ill) of Veravár find the small dendrite arms in a characteristic dendritic structure are of rather small size, and the alpha+ delta eutectoid among them is also rather scarce. /Fig. 1.3./ The unusually fast cooling of the ingot could be the result of intentional or unintentional intervention. Fast cooling could be produced e.g. by a ceramic-, sand- or sand stone- mould, which was not sufficiently warmed up, or by the use of metallic mould. As a rule, the boundaries of relatively small grains can hardly be observed inside the cast articles on (No. 174-188) the cut surfaces of ingots. Mostly several minor coloured areas, and the dark grey stains of the iron show the presence of impurities. Casting of discs should be usually performed under peculiar circumstances and not in closed forms, as it is demonstrated by strongly blistered surface on their more strait side and their porous structure. II. CAST AND COLD-WORKED ARTICLES As the studied samples show, among the cast articles those cold processed occur more frequently. This kind of processing is applied only on a part of the object, mostly on its edge. One can observe this method in the case of dagger (No. 9), cased hatchet (No. 21) and particularly of sickle (No. 46-47). At these polished surfaces one can observe in almost all cases that on the broader parts of the cross sections of the object, e.g. at the back side of the blade, at the edge of the socket or at the stiffener rib of the sickle, the original dendritic or polygonally crystallised texture remained, /Fig. 1.4./ in the proximity of the edge, however, very prolonged, more strongly corroded crystallites can be seen. /Fig.3.1., 2.1./ The small quantity of alpha+delta eutectoid among the dendritic arms is always an indication of low tin content (one can see on a single object that crystallisation often took place in different ways: dendritic on thicker parts and rather polygonal on thinner ones. /Fig. 1.4., 2.1-2./) Beside the compaction of the traces of cold working can be observed in cases where, obviously, the aim was not the modification of the microstructure and the material properties. Often this texture change can be regarded as a secondary collateral phenomenon of another work process. It is frequently observed with the sickles that at the joining of the arched blade and the handle prick there is a protruding section, the upper part of which, together with a part of the sickle back, has been flattened. On the flattened part one can mostly observe lentilshaped dimples, and at the edges cracked purr protruding over the plan of the material. On the picture of the sample taken from this area one can clearly observe the compacted texture. Its modification is considerable in the neighbourhood of the surface, but gradually decreases toward inside. III. WORKED, ANNEALED ARTICLES Most part of studied bronze objects consisted of worked, annealed objects. Among the objects worked again after the annealing one can find knife (No. 10. 17), needle (No. 77), fragment of tip (No. 79), fibula fragment (No. 88) and bronze pins alike. Particularly the small- size twinned grains indicate that the bronze material of the articles was extended to the intended size often after several annealing and the relatively soft material produced by annealing and fast cooling down, was hammered on its tip or edge only, up to a fairly hard state. /Fig.3.1.

,4./ Applying this process with a annealing and an end compacting, in spite of the low tin content a material of ideal structure had been obtained consisting practically of homogeneous alpha crystals, showing excellent hardness without being brittle. It can be observed particularly on the cuts of bronze pins, that the samples taken from various places show different pictures. Particularly on the articles made of bronze pin one can observe that the samples taken from different places show various pictures. E.g. at the side of a