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1

The selected manufacturing problems of the bulk metallic glasses

Pilarczyk W.

Selected Engineering Problems

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2013

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nr 4

139--142

EN

In this article selected problems that occur during the manufacture of bulk metallic glasses have been discussed. A number of different techniques to synthesize bulk metallic glasses (BMG) alloys have been developed. These developments have been occurred in different laboratories, for some specific applications or materials. In this paper the analysis of glass transition factors and the associated technological problems have been presented. The observations and gained experience during the preparation of iron-based and zirconium-based bulk metallic glasses prepared by die pressure casting method were the basis for this elaboration.

2

Observation of the complex local crystallization process in Ti-Zr-Cu-Pd amorphous ribbons and bulk metallic glass

Sypień A.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 2

347--350

EN

In recent years, bulk metallic glasses (BMGs) have attracted much attention, especially concerning the reasons for the high glass-forming ability. To understand properties and glass-forming ability of BMGs, it is important to investigate their atomic structure in details. The structure of the metallic glass, derived from diffraction studies, confines mainly to short-range-order atomic correlations, which are statistically averaged over the glassy specimens. In the present study, local structure of a BMG and ribbons was observed using a high-resolution TEM (TECNAI G2 FEG). The TEM images of the BMG before annealed in the temperature below the crystallization clearly reveal a duplex microstructure consisting of nanocrystalline particles about 5-10 nm in size distributed uniformly in the amorphous matrix. Due to the FFT research the crystalline phases may be indexed as the Cu8Zr3, Cu3Pd, CuTi2 and CuTiZr.

PL

W ostatnich latach dużym zainteresowaniem cieszy się poszukiwanie składów stopów, które charakteryzuje wysoka zdolność do tworzenia faz amorficznych, a co za tym idzie, tworzenia masywnych szkieł metalicznych. Aby zrozumieć właściwości oraz zdolność materiału metalicznego do zeszklenia należy zbadać szczegółowo jego strukturę atomowa. Badania dyfrakcyjne metali amorficznych pozwalają jedynie na uzyskanie informacji na temat uporządkowania bliskiego zasięgu. Niniejsza praca przedstawia bardziej wnikliwe badania lokalnej struktury szkieł metalicznych, które uzyskano przy użyciu transmisyjnej mikroskopii elektronowej TEM. Wybrany stop o składzie Ti40Zr10Cu40Pd10 został poddany wygrzewaniu w temperaturze poniżej temperatury krystalizacji. Badania HREM ujawniły, iż powstała w materiale mikrostruktura składała się z nanocząstek o wielkości około 5-10nm w amorficznej osnowie. Analizy składu chemicznego EDX oraz obrazów transformaty Fouriera wskazują, iz krystaliczne fazy mogą być zidentyfikowane jako Cu8Zr3, Cu3Pd, CuTi2 i CuTiZr.

3

Preparation and glass-forming ability of Mg-based bulk amorphous alloys

Babilas R., Zajączkowski A., Głuchowski W., Nowosielski R.

Archives of Materials Science and Engineering

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2013

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Vol. 62, nr 2

78--86

EN

Purpose: The work presents preparation methods, structure characterization and glass-forming analysis of Mg-based bulk metallic glasses in as-cast state. Design/methodology/approach: The studies were performed on Mg60Cu30Y10 and Mg60Cu29Y10Si1 glassy alloys in the form of plates and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD). The thermal properties associated with solidus and liquidus temperature of master alloys were measured using the differential thermal analysis (DTA). The crystallization behavior of the studied plates and rods was also examined by differential scanning calorimetry (DSC). The fracture morphology of the rods in as-cast state was analyzed using the scanning electron microscopy (SEM). Findings: The X-ray diffraction investigations revealed that the tested samples with different thickness and shape were amorphous. The single exothermic peaks describing crystallization process of studied alloys were observed for all examined samples with different thickness. The endothermic and exothermic peaks observed on DTA curves of master alloys allowed to determine the solidus and liquidus temperatures. The characteristics of the fractured surfaces showed different zones, which might correspond with different amorphous structures. The changes of glass transition and crystallization temperatures as a function of sample thickness were stated. Practical implications: The pressure die casting method are useful technique to fabricate bulk amorphous materials in the form of plates and rods. Proposed casting technology could open new possibilities to easier preparation of Mg-based nanostructured materials and forming their properties that is essential for further applications. Originality/value: The Mg-based bulk amorphous alloys are regarded as promising engineering materials with high strength, low density and good corrosion resistance in contrast to the crystalline alloys, due to their different atomic configurations

4

Influence of casting parameters on thermal properties of bulk metallic glass Cu48 Zr 36Ag11Ti5

Błyskun P., Latuch J., Kulik T.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 3

670-672

EN

Bulk metallic glasses are sensitive for parameters related to technological process. Thermal stability of metallic glasses and their structure depends on chemical composition and manufacturing conditions. In this work the influence of copper-based bulk metallic glass casting parameters on its thermal properties is studied. A couple of rod-shaped samples were produced by casting method into a copper mold. Structures of samples as well as thermal properties were investigated. Dependence of thermal properties on casting parameters (temperature, pressure) has been determined. A short discussion about probable reason of this dependence is presented. Finally, the parameters that give the opportunity to achieve an optimal thermal properties were selected.

PL

Stosunkowo nowe materiały, jakimi są masywne szkła metaliczne, wykazują dużą czułość na parametry procesu wytwarzania. Stabilność cieplna szkieł metalicznych i ich struktury zależy nie tylko od składu chemicznego, ale także od warunków wytwarzania. W artykule zawarty jest opis wpływu parametrów procesu odlewania masywnego szkła metalicznego na osnowie miedzi na jego właściwości cieplne. Wytworzono serię próbek w zmiennej temperaturze i rożnym ciśnieniu odlewania. Przeprowadzono badania strukturalne oraz badania cieplne wytopionych próbek. Określono zależność właściwości cieplnych od parametrów procesu odlewania. Przedstawiono krotką dyskusję na temat prawdopodobnego źródła tej zależności. Ostatecznie wytypowano parametry, które pozwalają uzyskać szkło o optymalnych właściwościach cieplnych.