Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

2 Journal of Achievements in Materials and Manufacturing Engineering

2 2010

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: szkło wysokometalowe

Sortuj według:

Ogranicz wyniki do:

Structure, thermal and magnetic properties of Fe43Co14Ni14B20Si5Nb4 bulk metallic glass

100%

Nowosielski R. , Babilas R. , Griner S. , Czeppe T.

tom Vol. 38, nr 2

123-130

Purpose: The paper presents structure characteristics, thermal stability and soft magnetic properties analysis of Fe-based bulk metallic glass in as-cast state and after crystallization process. Design/methodology/approach: The studies were performed on Fe43Co14Ni14B20Si5Nb4 metallic glass in a form of 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 stability of the glassy samples was measured using differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained initial magnetic permeability and magnetic permeability relaxation measurements. Findings: The XRD and TEM investigations revealed that the studied as-cast plates and rods were amorphous. Broad diffraction halo could be observed for all tested samples, indicating the formation of a glassy phase with the diameters up to 3 mm for rods. The fracture surface of rod samples appears to consist of two different zones which might correspond with different amorphous structures of studied materials. The thermal stability parameters of rod with diameter of 3 mm, such as glass transition temperature, onset crystallization temperature and supercooled liquid area were measured by DSC to be 797 K, 854 K, 57 K, respectively. The heat treatment process of rod samples involved in crystallization of á-Fe phase and formation of iron borides at temperature above 873 K. Practical implications: The appropriate increase of annealing temperature significantly improved soft magnetic properties of examined alloy by increasing the initial magnetic permeability and decreasing the magnetic permeability relaxation. Originality/value: The success of fabrication of studied Fe-based bulk metallic glass in a form of plates and rods is important for the future progress in research and practical application of those glassy materials.

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

100%

Nowosielski R. , Januszka A.

tom Vol. 38, nr 1

15-23

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.