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1

The study of structure and glass forming ability of Zr-based amorphous alloy

Pilarczyk W.

Archives of Materials Science and Engineering

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2013

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Vol. 63, nr 1

19--25

EN

Purpose: This paper tends to present the structure and thermal analysis of selected Zr-based amorphous alloy for welding processes. Design/methodology/approach: The studies were performed on Zr-Cu-Ni-Al system alloy in form of plate. The structure analysis of the studied materials in as-cast state was carried out using XRD method. The thermal properties of the as-cast alloy were examined by DSC and DTA methods. The parameters of GFA included Trg, ΔTx, α, β, γ, δ and S were calculated. Findings: The Zr-based amorphous alloy in form of plate with good GFA was produced by die pressure casting method. The investigation methods revealed that the studied as-cast alloy was amorphous. Although, there is probability of crystallites existence which could not be detected by XRD method. The literature study and calculated GFA parameters indicated that the Zr55Cu30Ni5Al10 alloy exhibits good GFA and thermal stability. It is confirmed that these parameters could be used to determine GFA of tested amorphous alloy for welding processes. This Zr-based BMG could be used as tested material for laser welding process. Research limitations/implications: It is very difficult to obtain a Zr-based BMG with large sizes. Usually, the difficulties of the production of zirconium amorphous alloy are connected with the fact that the constituent elements of the analyzed materials have a high chemical affinity for oxygen, and have different melting points. For this reason, the process of producing BMG in zirconium matrix require the using of additional technology to provide specific conditions for the melting and casting. Practical implications: These obtained values of GFA parameters can suggest that studied alloys are suitable materials for further practical application at welding process. Originality/value: The success formation and investigation of the casted Zr-based BMG. The chemical composition of Zr55Cu30Ni5Al10 alloy was tested first time in our laboratory.

2

Structure and properties of Fe-Cr-Mo-C bulk metallic glasses obtained by die casting method

Pilarczyk W., Nowosielski R., Januszka A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

80-87

EN

Purpose: The goal of this work is to investigate structure and properties of Fe54Cr16Mo12C18 alloy rods with different diameters obtained by the pressure die casting method. Design/methodology/approach: Master alloy ingot with compositions of Fe54Cr16Mo12C18 was prepared by induction melting of pure Fe, Cr, Mo, C elements in argon atmosphere. The investigated material were cast in form of rods with different diameters. Glassy and crystalline structures were examined by X-ray diffraction. The microscopic observation of the fracture morphology was carried out by the SEM with different magnification. The thermal properties of the studied alloy were examined by DTA and DSC method. Findings: These materials exhibit high glass-forming ability, excellent mechanical properties and corrosion resistance. Research limitations/implications: It is difficult to obtain a metallic glass of Fe54Cr16Mo12C18 alloy. The investigations carried out on the different samples of Fe54Cr16Mo12C18 bulk metallic alloy allowed to state that the studied ribbon was amorphous whereas rods were amorphous – crystalline. Originality/value: The formation and investigation of the casted Fe-Cr-Mo-C bulk materials and the study of glass-forming ability of this alloy.

3

Preparation, structure and properties of Fe-based bulk metallic glasses

Nowosielski R., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 40, nr 2

123-130

EN

Purpose: The work presents preparation methods, structure characterization and chosen properties analysis of Fe-based bulk metallic glasses in as-cast state. Design/methodology/approach: The studies were performed on Fe43Co14Ni14B20Si5Nb4 metallic glass in form of rings, plates 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 was measured using differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained coercive force, initial magnetic permeability and magnetic permeability relaxation measurements. Findings: The XRD and TEM investigations revealed that the studied as-cast samples were amorphous. Broad diffraction halo is typical for metallic amorphous structures that have a large degree of short-range order. The characteristics of the fractured surfaces showed different zones, which might correspond with different amorphous structures of studied materials. The temperature interval of the supercooled liquid region (ÄTx) defined by the difference between Tg and Tx, is as large as 56 K for the rod with diameter of 3 mm. Differences in coercivity and magnetic permeability between samples with different thickness might be resulted by some difference of amorphous structure. Practical implications: The centrifugal casting method and the pressure die casting method are useful to produce bulk amorphous materials in form of rings, plats and rods. Originality/value: The preparation of studied Fe-based bulk metallic glass in form of rings, plates and rods is important for the future progress in research and practical application of that glassy materials.

4

Influence of nickel on structure and hardness of Fe-Co bulk metallic glasses

Nowosielski R., Januszka A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 38, nr 1

15-23

EN

Purpose: In the present paper, influence of Ni addition on structure and hardness Fe-based bulk metallic glass were investigated. Design/methodology/approach: The studies were performed on Fe36+xCo36-x-yNiyB19.2Si4.8Nb4 ( x= 0;1, y=0;10;15) glassy alloy in a form of rods with diameter up to 5 mm. The tests, carried out to obtain amorphous metallic glasses, were realized with the use pressure die casting method. The system includes a copper mould, high frequency power supply, quartz nozzle and a source of inert gas as argon. The following experimental techniques were used for the test of structure: X-ray diffraction (XRD) phase analysis and scanning electron microscopy (SEM). Microhardness was examined by Vickers diamond testing machine. Findings: The X-ray diffraction revealed that all samples with thickness 2 mm were amorphous. The structural studies revealed that amorphous structure depended on thickness and nickel contents in a preliminary alloy. Research limitations/implications: The relationship between structure and microhardness can be useful for practical application of these alloys. Practical implications: The Fe-based bulk metallic glasses attracted great interest for a variety of application fields, for example structural materials, electric applications, precision machinery materials. These amorphous alloys exhibit high strength, a high elastic strain limit, high fracture toughness, and other useful mechanical properties which are attractive to many engineering applications. Originality/value: The originality of this paper are studies of changes of structure and hardness of Fe36+xCo36-x-yNiyB19.2Si4.8Nb4 ( x= 0;1, y=0;10;15) mainly depending on Ni addition in this alloy.

5

Glass-forming ability analysis of selected Fe-based bulk amorphous alloys

Nowosielski R., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

66-72

EN

Purpose: The paper mainly aims to present the structure and thermal stability of selected Fe-based bulk metallic glasses: Fe72B20Si4Nb4 and Fe43Co14Ni14B20Si5Nb4. Design/methodology/approach: The investigated samples were cast in form of the rods by the pressure die casting method. The structure analysis of the studied materials in as-cast state was carried out using XRD and TEM methods. The thermal stability associated with glass transition temperature (Tg), onset (Tx) and peak (Tp) crystallization temperature was examined by differential scanning calorimetry (DSC). Several parameters have been used to determine the glass-forming ability of studied alloys. The parameters of GFA included reduced glass transition temperature (Trg), supercooled liquid region (deltaTx), the stability (S) and (Kgl) parameter. Findings: The XRD and TEM investigations revealed that the studied as-cast metallic glasses were fully amorphous. Changes of the onset and peak crystallization temperature and the glass transition temperature as a function of glassy samples thickness were stated. The good glass-forming ability (GFA) enabled casting of the Fe72B20Si4Nb4 and Fe43Co14Ni14B20Si5Nb4 glassy rods. Practical implications: The obtained examination results confirm the utility of applied investigation methods in the thermal stability analysis of examined bulk amorphous alloys. It is evident that parameters Trg, deltaTx, Kgl, S could be used to determine glass-forming ability of studied bulk metallic glasses. Originality/value: The success of fabrication of studied Fe-based bulk metallic glasses in form of rods with diameter up to 3 mm is important for the future progress in research of this group of materials.

6

Glass forming ability of binary Ni60+xNb40-x (x=0;1;2) alloys

Nowosielski R., Januszka A., Pilarczyk W.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

73-80

EN

Purpose: This paper presents the investigations results of fabrication and structure tests binary Ni-Nb metallic glasses. Design/methodology/approach: The studies were performed on Ni60+xNb40-x (x=0, 1, 2) alloys in form of ribbon and rods up to 2 mm. For the purpose of fabrication test pieces, melt spinning and pressure die casting methods were used. The main index for determine glass forming ability was thickness of specimens. To the tests of samples structure X-ray diffraction phase analysis (XRD) and scanning electron microscopy (SEM) were used. Owing to good mechanical properties of Ni-based metallic glasses, microhardness of cast rods were examined. Findings: X-ray diffraction and SEM analysis have revealed that samples in form of ribbons were amorphous, while cast rods were crystalline. Practical implications: The relationship between amorphous structure and good mechanical properties could be promising for many engineering application. The Ni-based bulk metallic glasses are newcomers engineering materials which may be applied to a new type pressure sensor exhibiting higher capability and higher sensitivity Originality/value: Paper present quite new type of binary metallic glasses based on Ni. For the sake of alloy simplicity it is possible that this alloys will be used in many applications.