Abstract
Properties of Co-based alloys with high Glass Forming Ability (GFA) in the form of powder are still not widely known. However, powders of high GFA alloys are often used for the development of bulk metallic glasses by additive manufacturing. In this work Co47.6B21.9Fe20.4Si5.1Nb5% at. and Co42B26.5Fe20Ta5.5Si5Cu1% at. were developed by gas-atomization. Obtained powders in size 50–80 µm were annealed at Tg and Tx of each alloy. Then SEM observation, EDS analyses, differential thermal analysis, X-ray diffraction, nanoindentation, Mössbauer, and magnetic properties research was carried out for as-atomized and annealed states. The gas atomization method proved to be an efficient method for manufacturing Co-based metallic glasses. The obtained powder particles were spherical and chemically homogeneous. Annealing resulted in an increase of mechanical properties such as hardness and the elastic module of Co47.6B21.9Fe20.4Si5.1Nb5% at and Co42B26.5Fe20Ta5.5Si5Cu1%, which was caused by crystallization. The magnetic study shows that Co47.6B21.9Fe20.4Si5.1Nb5 and Co42B26.5Fe20Ta5.5Si5Cu1 are soft magnetic and semi-hard magnetic materials, respectively.
Highlights
Researchers [3,4,5] proved that atomization is a proper method to prepare amorphous alloys in a powder form
The results of the particle size analysis showed that 50% of the particle size (D50) for the granulation of 20–50 μm granulation had a diameter less than or equal to
Based on the results shown in this work, atomization was confirmed as a suitable method to obtain powder-form alloys with high glass formation ability (GFA), including
Summary
The melted alloy needs to be cooled at a speed higher than the critical cooling rate. This cooling stops dynamic atom diffusion and enables the development of an amorphous solid-state structure of a metal alloy [3]. Researchers [3,4,5] proved that atomization is a proper method to prepare amorphous alloys in a powder form. Research shows that fully vitrification of powders depends on the size of obtained particles [6] and glass-forming ability of the processed alloy [7]. In article [8] researchers were able to simulate an atomization process for a Fe-based alloy with high glass forming ability. Obtained powders were fully amorphous for particle size 25–45 μm
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