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1

Evaluation of metallurgical quality of master heat IN-713C nickel alloy ingots

Binczyk F., Cwajna J., Roskosz S., Gradoń P.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 4

5-10

EN

The paper presents the results of evaluation of the metallurgical quality of master heat ingots and of the identification of non-metallic inclusions (oxides of Al., Zr, Hf, Cr, etc.), which have been found in the shrinkage cavities formed in these ingots. The inclusions penetrate into the liquid alloy, and on pouring of mould are transferred to the casting, especially when the filtering system is not sufficiently effective. The specific nature of the melting process of nickel and cobalt alloys, carried out in vacuum induction furnaces, excludes the possibility of alloy refining and slag removal from the melt surface. Therefore, to improve the quality of castings (parts of aircraft engines), it is so important to evaluate the quality of ingots before charging them into the crucible of an induction furnace. It has been proved that one of the methods for rapid quality evaluation is an ATD analysis of the sample solidification process, where samples are taken from different areas of the master heat ingot. The evaluation is based on a set of parameters plotted on the graph of the dT/dt derivative curve during the last stage of the solidification process in a range from TEut to Tsol.

2

Effect of repeated remelting on the chemical composition and structure of nickel alloys

Binczyk F., Śleziona J., Mikuszewski T.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

189--194

EN

The results of preliminary tests and studies on the effect of repeated remelting of selected nickel alloys on changes in the chemical composition and structure were presented. The aim was to investigate possible management and utilisation of post-production waste (rejects, parts of the gating system, etc.). It has been reported that repeated remelting of IN-713C alloy had no significant effect on changes in its chemical composition. Only aluminium slightly reduced its content due to melting loss, as confirmed further by the results of ATD thermal analysis. On the other hand, in MAR-247 alloy after remelting, a decrease in the content of Cr, Ta, Hf, and C in particular, was observed. To re-use the post-production waste, it is necessary to make up the content of some elements (especially trace elements) and carry out the modification process.

3

Studies on sol-gel processes accompanying formation of the yttrium aluminum garnet nanocrystals

Loiko E. M., Lipińska L., Dobrowolski J. C., Rzepka A.

Materiały Elektroniczne

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2006

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T. 34, nr 3-4

74-88

EN

The sol-gel processes of YAG and YAG doped Nd are presented. The mechanism of YAG powders formation by sol-gel method is described. The gel is formed by reaction of inorganic salts or oxides Y, Al, Nd elements with acetic acid and ethylene glycol. Conditions of sol-gel processes in the range of temperature treatment from 100°C to 1000°C and mechanism of reactions are investigated using DTA, X-ray diffraction and infrared spectroscopic methods. Size, shape, and morphology of the surface of the YAG powders are characterized by scanning electron microscope. Finally one phase of YAG and yttrium substituted by neodymium up to 28% at. are found. At higher concentration of Nd (up to 100% at.) two phases of garnet and perovskite type are detected.

PL

Metodę zol-żel wykorzystano do otrzymywania nanokrystalicznych granatów YAG i YAG:Nd. Przedstawiono mechanizm powstawania proszków o krystalicznej strukturze granatu. Odpowiednie żele otrzymywano w reakcji nieorganicznych soli lub tlenków pierwiastków Y, Al, Nd z kwasem octowym i glikolem etylenowym. Poszczególne etapy procesu zol-żel oraz reakcje zachodzące podczas obróbki termicznej kserożeli w zakresie od 100°C do 1000°C badano metodami: analizy termicznej DTA, dyfrakcji rentgenowskiej XRD, oraz spektroskopii w podczerwieni IR. Rozmiar, kształt oraz morfologię powierzchni proszków charakteryzowano za pomocą skaningowej mikroskopii elektronowej SEM. Otrzymano jednofazowe proszki czystego granatu YAG i domieszkowanego neodymem w ilościach aż do 28%. Dla wyższych zawartości neodymu (do 100%) obserwowano występowanie dwóch faz - granatu i perowskitu.