In this study a simple procedure for the in situ identification of the intermetallic phase precipitates in the interdendritic eutectic in both wrought and cast AlFeMnSi alloys has been established and then verified by experimental results. Morphology of the phase constituents of these eutectics: A6MnFe, αc-AlFeMnSi, αH-AlFeSi, β-AlFeSi, has been revealed on the metallographic microsections, observed with light and scanning electron microscopes. Chemical composition of these phase precipitates was estimated by means of point x-ray microanalysis. The homogeneity range for particular intermetallic phase precipitates, as influenced by either alloy chemical composition or microstructure morphology, was estimated.
Keywords: Al alloys, microstructure, intermetallic phase, x-ray microanalysis, local chemical composition,
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Marta Homa, Aleksandra Siewiorek, Andrzej Gazda, Natalia Sobczak, Artur Kudyba, Patrycja Turalska, Katarzyna Pietrzak, Krystyna Frydman, Danuta Wójcik-Grzybek, Agata Strojny-Nędza
The paper presents results of preliminary studies on Ag-C materials obtained using the powder metallurgy (PM) method with carbon nanotube doping. Based on structural tests performed using scanning electron microscopy and DSC, DIL and LFA tests of thermophysical properties, it was ascertained that the utilised procedure of producing composite material does not ensure satisfactory distribution of the carbon phase in the metal matrix. In order to improve the uniformity of Ag-C materials, a new method of deagglomerating the carbon phase needs to be developed.
Keywords: Ag-C composites, carbon nanotuvbes, thermophysical properties,
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Zdzisław Żółkiewicz, Stanisław Młodnicki, Jacek Krokosz, Rafał Pabiś, Ryszard Ćwiklak
Research was carried out on the technological properties of plaster mixtures developed at the Foundry Research Institute. Developed were mixtures of ceramic compounds in which the basic material was synthetic plaster. The components of the developed compound were examined in order to determine basic technical and commercial properties. The test results are presented in the figures.
Keywords: artistic casting, casting mould, ceramic casting mould, plaster, non-ferrous metal casting,
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Andrzej Gazda, Małgorzata Warmuzek, Edward Czekaj
The publication presents the results of optimisation of parameters of complex heat treatment of as-cast AlZnMgCu(Mn) alloys consisting in retrogression and reaging (RRA, Retrogression and Re-aging). For comparison purposes, the analysis of a standard T6 heat treatment and a T7 heat treat-ment (according to PN-EN 515:1996) which improve resistance to stress corrosion cracking (SCC) were carried out. To optimise the parameters of heat treatment the thermal analysis method - Differential Scanning Calorimetry (DSC), measurements of electrical conductivity and microstructural observations were conducted. Selected variants of heat treatment for optimal parameters determined in the study were realized and tensile tests were performed. The highest values of Rm were achieved after RRA (200°C/20 min) heat treatment and higher values for alloy with a higher content of copper were obtained. The results obtained in this study demonstrate the efficiency of the modification of the alloys’ microstructure by means of the RRA heat treatment, confirmed by the results of tensile tests and fracture surface observations. The results of DSC studies of material after various stages of the planned heat treatments may provide a starting point to study the mechanism of the associated phase transformations and can serve as inspiration for further research on the as-cast AlZnMgCu alloys.
Keywords: AlZnMgCu alloys, Retrogression and Re-ageing (RRA), Dilatometry, Differential Scanning Calorimetry (DSC),
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