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1

Fabrication of Mg65Cu25Y10 bulk metallic glasses

100%

Nowosielski R. , Babilas R. , Guwer A. , Gawlas-Mucha A. , Borowski A.

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tom Vol. 53, nr 2

77-84

EN

Purpose: The paper describes the preparation, structure and thermal properties of Mg-based bulk metallic glass with chemical composition of Mg65Cu25Y10 in form of as-cast rods. Design/methodology/approach: The investigations on the Mg65Cu25Y10 glassy rods were conducted by using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) methods. Findings: The X-ray diffraction investigations have revealed that the studied as-cast rod was amorphous. The DSC curve informs about the single stage of crystallization process. The onset crystallization temperature has a value of Tx = 463 K and peak crystallization temperature reaches a value of Tp = 480 K. The fractures of studied alloy could be classified as mixed fracture with indicated “river” and “smooth” fractures. Both type of the fracture surfaces consist of weakly formed “river” and “shell” patterns and “smooth” regions. The “river” patterns are characteristic for metallic glassy alloys. Practical implications: The studied Mg-based bulk metallic glasses are applied for many applications in different elements. Mg-based bulk metallic glasses have much higher tensile strength and Vickers hardness and much lower Young’s modulus in contrast to crystalline magnesium alloys. Magnesium alloys are very attractive for transport and aerospace applications because they are the lightest among the commercially available structural alloys and show excellent damping capacity. Originality/value: Fabrication of amorphous alloy rod Mg65Cu25Y10 by pressure die casting method.

2

Fabrication of bulk metallic glasses by centrifugal casting method

84%

Nowosielski R. , Babilas R.

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tom Vol. 20, nr 1-2

487-490

EN

Purpose: The aim of the present work is characterization of the centrifugal casting method, apparatus and produced amorphous materials, which are also known as bulk metallic glasses. Design/methodology/approach: The studied centrifugal casting system consists of two main parts: casting apparatus and injection system of molten alloy. The described centrifugal casting method was presented by preparing a casting apparatus "CentriCast - 5". The apparatus includes a cylindrical copper mold, which is rotated by a motor. The transmission allows to changing the speed of rotating mold. Findings: Bulk metallic glasses are a novel class of engineering materials, which exhibit excelent mechanical, thermal, magnetic and corrosion properties. Centrifugal casting is a useful method to produce bulk amorphous materials in form of rings, tubes or cylindrical parts. Presented centrifugal casting method and casting apparatus has been prepared to fabricate the samples of bulk metallic glass in form of rings with an outer diameter of 25 mm and controlled thicknesses by changing the weight of the molten alloy. Research limitations/implications: Studied centrifugal casting method and casting apparatus has been prepared to fabricate the samples of bulk metallic glass. For future research a characterization of microstructure and properties of prepared material will be performed. Practical implications: The centrifugal casting is a useful process to produce bulk amorphous materials in form of rings, tubes or graded amorphous matrix composites. It seems to be a very simple method, which allows to obtain BMG materials. Originality/value: The centrifugal casting method allows to produce bulk amorphous rings with thickness above 1-mm.

3

Bulk metallic glasses based on magnesium to potential biomedical application

84%

Kiljan A. , Nowosielski R.

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tom nr 6

41--44

EN

The paper presents some informations about materials for biomedical application. The study was performed on ternary Mg-based alloys. The Mg66Zn30Ca4 glassy alloy was prepared in the form of rods by pressure die casting method of molten alloy into water cooled copper mold. This alloy is potential material for biomedical application.

4

Structure and soft magnetic properties of Fe72B20Si4Nb4 bulk metallic glasses

84%

Nowosielski R. , Babilas R. , Griner S. , Stokłosa Z.

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tom Vol. 35, nr 1

13-20

EN

Purpose: The paper presents a microstructure characterization, thermal stability and soft magnetic properties analysis of Fe-based bulk amorphous materials. Design/methodology/approach: The studies were performed on Fe₇ ₂B₂ ₀Si₄Nb₄ glassy alloy in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The magnetic properties were determined by the Maxwell-Wien bridge and VSM methods. Findings: The X-ray diffraction and transmission electron microscopy investigations have revealed that the studied as-cast bulk metallic glasses were amorphous. Broad diffraction halo can be seen for all tested samples, indicating the formation of a glassy phase with the diameters up to 2 mm. The fracture surface of rod samples appears to consist of small fracture zones, which leads to breaking of the samples into parts. A two stage crystallization process was observed for studied amorphous alloy. The changes of crystallization temperatures and magnetic properties as a function of glassy samples thickness were stated. Practical implications: The studied Fe-based alloy system has good glass-forming ability and thermal stability for casting bulk metallic glasses, which exhibit good soft magnetic properties, useful for many electric and magnetic applications. Originality/value: The obtained examination results confirm the utility of applied investigation methods in the microstructure, thermal and soft magnetic properties analysis of examined bulk amorphous alloys.

5

The production attempt of Fe-Nb-B-Zr and Fe-Nb-B-Y system alloys by die pressure casting method

84%

Pilarczyk W. , Kucharczyk M.

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2013

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tom Vol. 61, nr 2

222-228

EN

Purpose: The purpose of this article was to investigate the possibility of the production of Fe-Nb-B bulk metallic alloys with additions of yttrium and zirconium elements. Furthermore, this paper tends to present the structure and selected properties of obtained alloys. In this article the influence of an argon atmosphere on casting process was observed too. Design/methodology/approach: The production attempts were performed on Fe-Nb-B-Zr and Fe-Nb-B-Y system alloys in form of a plate. Master alloy ingots with compositions of Fe72B22Y4Nb2 and Fe71(Nb0.8Zr0.2)6B23 were prepared by induction melting of pure Fe, Nb, B, Y and Fe, Nb, B, Zr elements in an argon atmosphere. The ingots have been crushed and then the investigated material was cast with and without a protective atmosphere. The investigated materials were cast in form of a plate with thickness of 1 mm. The structure analysis of the studied materials in as-cast state was carried out using X-ray diffraction (XRD) and microscopic observation. The thermal properties of the alloys were examined by DSC methods. The measurments of the hardness were performed with the Vickers method. Findings: The Fe-Nb-B-Y and Fe-Nb-B-Zr system alloys in form of a plate were produced by die pressure casting method. The investigation methods revealed that the studied as-cast alloys were crystalline. The structure of the obtained plates is rather fine-grained and there were not found any impurities and undesirable phases inside the materials. The results of calorimetric curves confirm that all tested samples are crystalline. Practical implications: To extend the potential applications of the Fe-based BMGs, amorphous alloys with larger critical sizes and better processability are required. The Fe-Nb-B-Zr and Fe-Nb-B-Y bulk metallic glasses obtained by die pressure casting method can be used for production of telecommunications devices, sensors or low-energy transformers. These materials exhibit excellent mechanical and soft magnetic properties. Originality/value: An overall presentation of an influence of the yttrium and zirconium additions on the attempt of forming Fe72B22Y4Nb2 and Fe71(Nb0.8Zr0.2)6B23 alloys. The chemical composition of these alloys was tested in our laboratory for the first time.