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Kaptay G.,Bay Zoltan Applied Research Public Nonprofit Ltd. | Kaptay G.,University of Miskolc
Materials Science Forum | Year: 2014

In solidification experiments of binary eutectic alloys, the eutectic spacing and undercooling are measured as function of the solidification rate. A new theoretical relationship is derived herewith between the Gibbs-Thomson coefficient and the above mentioned values for both lamellar and rod type eutectics. This new equation allows the estimation of the interfacial energy between eutectic solid phases. For the Sn/Pb eutectics the value of about 0.15 N/m is found in this paper using experimental literature data on eutectic solidification experiments. This is consistent with an earlier value obtained by a more complex experimental method of Gündüz and Hunt. © (2014) Trans Tech Publications, Switzerland.

Baumli P.,Bay Zoltan Applied Research Public Nonprofit Ltd. | Baumli P.,University of Miskolc | Sychev J.,Bay Zoltan Applied Research Public Nonprofit Ltd. | Budai I.,Bay Zoltan Applied Research Public Nonprofit Ltd. | And 4 more authors.
Composites Part A: Applied Science and Manufacturing | Year: 2013

Here we show that carbon fiber (CF) reinforced aluminum (Al) matrix composite with homogenously dispersed (57 ± 11 vol.%) carbon fibers can be fabricated without any external pressure, although usually some external pressure is needed to fabricate such composites due to their non-wetting character. CFs were transferred into liquid Al using a special flux (molten salt), containing K 2TiF 6 dissolved in NaCl-KCl. This flux ensures the removal of oxides from the interfaces and the formation of a wettable TiC layer at the interfaces. The oxide-free and in situ TiC-coated CF showed perfect wettability by the de-oxidized liquid Al under the same flux, and thus the composite was formed in a spontaneous way, i.e. without applying any external pressure or mixing. © 2012 Elsevier Ltd. All rights reserved.

Juhasz K.L.,Bay Zoltan Applied Research Public Nonprofit Ltd. | Juhasz K.L.,University of Miskolc | Baumli P.,Bay Zoltan Applied Research Public Nonprofit Ltd. | Baumli P.,University of Miskolc | And 2 more authors.
Materialwissenschaft und Werkstofftechnik | Year: 2012

Carbon fibres (CF) reinforced aluminium (Al) matrix composite material was fabricated using a special flux of potassium iodide (KI) with 10 weight% of potassium hexafluoro-titanate (K 2TiF 6) at 820°C under protective argon atmosphere. The fabrication was performed with no extra pressure or mixing applied. Liquid Al spontaneously penetrated the space between the carbon fibres (or single fibres were spontaneously transferred from molten salt into liquid Al), due to the perfect wettability between these phases and the corresponding action of the interfacial capillary force. Perfect wettability is ensured by the formation of a thin metallic titanium carbide layer at the fibres/aluminium interface. Metallic titanium appears in liquid Al due to its exchange reaction with the K 2TiF 6 content of the molten salt. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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