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1

The composition of reaction substrates for TiC carbides synthesis and its influence on the thickness of iron casting composite layer

Olejnik E., Janas A., Kolbus A., Sikora G.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 2 spec.

165--168

EN

The effect of reaction substrates for the TiC carbide synthesis on the composite layer thickness produced in cast iron was examined. It was found that, at a constant weight of the charge amounting to 0.5 kg, changing the weight of the, placed in mould, stoichiometric mixture of titanium carbide (from 0.01 to 0.04 kg) changed the thickness of the composite layer from 1 to 15 mm. Carbides synthesis starts directly in mould induced by the temperature of molten alloy poured into this mould (1700 K). The TiC carbides formed in this reaction are later, i.e. during alloy solidification, acting as a base composite material. The size of TiC carbides obtained in the synthesis is from 1 to 10 μm. They occur in the layers as locally compact and coagulated forms. Microstructure, chemical composition and structure of the obtained materials were tested by scanning electron microscopy (SEM), X-ray microanalysis (EDS), and X-ray diffraction (XRD).

2

The morphology of TiC carbides produced in surface layers of carbon steel castings

Fraś E., Olejnik E., Janas A., Kolbus A.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 4

39--42

EN

The study presents the results of investigations of the process of in situ fabrication of TiC carbides in a surface layer of carbon steel casting. Carbides were produced by SHS reaction taking place between the substrates deposited on mould surface and cast molten alloy. The thickness of the obtained layer was up to 700 μm, and the size of carbides was comprised in a range of 1-10μm. During alloy solidification in mould, a thermal analysis was carried out; its results were used in evaluation of the morphology of the obtained titanium carbides. It has been found that, at the moment of reaction, the temperature of the reaction layer and the temperature of the central part of casting differed by 93 K. This difference has changed the morphology of the obtained carbides. In the region of reaction layer, where the temperature amounted to 1955 K, the crystals assumed an oval and coagulated shape, while at the layer-casting interface, TiC carbides in the form of cuboids were formed.

3

Fabrication of in situ composite layer on cast steel

Fraś E., Olejnik E., Janas A., Kolbus A.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

175--180

EN

The study describes the technology of fabrication of composite layers in cast steel reinforced with titanium carbides. In the process under discussion, the reinforcing TiC phase is formed in situ from the substrates deposited on mould cavity, where the said substrates under the effect of heat supplied by molten metal poured into mould (1823K) undergo a synthesis in the SHS reaction. An outcome of this process is the formation, within the casting surface, of a layer from 550 to 1200μm thick. Carbides produced in this synthesis have the size from 0,5 to 20μm and a non-typical spheroidal shape. The hardness of the produced layer examined in function of the distance from the casting surface is from 700 to 1134 HV, and is determined by volume fraction of the reinforcing TiC phase. To better document the type of microstructure obtained in the produced material, metallographic and structural examinations were carried out using the method of scanning electron microscopy (SEM), X-ray microanalysis (EDS/EDX), and phase analysis (XRD). To check the mechanical properties of the examined material, hardness was measured by the Vickers test.

4

Aluminiowe kompozyty z hybrydowym umocnieniem faz międzymetalicznych i ceramicznych

Dolata-Grosz A., Formanek B., Śleziona J., Wieczorek J.

Archiwum Odlewnictwa

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2004

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R. 4, nr 14

126-131

PL

W artykule przedstawiono proces otrzymywania odlewanych kompozytów aluminiowych o dyspersyjnej strukturze i hybrydowym umocnieniu. Stop aluminium modyfikowano mieszaninami proszków, które w reakcji z aluminium umacniały osnowę fazami międzymetalicznymi i tlenkiem aluminium. Fazy zbrojące otrzymano stosując proszki kompozytowe w układach Fe-Ti-AI oraz Fe-TiC-AI z tlenkiem glinu, uzyskane w procesie samorozwijającej się syntezy wysokotemperaturowej (SHS). Stosując metodę odlewniczą (mechanicznego mieszania) wytworzono kompozytowe stopy: AI-FeAI-TiAI-A_2O_3 oraz AI-FeAl_3- TiC-Al_2O_3 i określono ich strukturę. Opracowany proces wytwarzania kompozytów pozwala w różnych wariantach technologicznych na modyfikację struktury stosowanych odlewniczych stopów aluminium.

EN

The process of obtaining cast aluminium composite of dispersive structure has been presented in the article. Aluminium alloys were modified with powder mixtures which, when in reaction with aluminium, reinforced the matrix by means of intermetallic phases and aluminium oxide. The reinforcing phases were obtained by means of Fe-Ti-AI and Fe-TiC-AI powder mixtures with aluminium oxide formed during high-temperature synthesis process (SHS). Composite alloys AI-FeAI-TiAI-A_2O_3 and AI-FeAl_3- TiC-Al_2O_3 were produced. The structure of alloys produced by gravity/centrifugal casting was determined. The designed process allows for the structure modification of casting aluminium alloys in technological variants.