Glass-Forming Ability and Soft Magnetic Properties of (Co75Ti25)100−xFex (x; 0–20 at.%) Systems Fabricated by SPS of Mechanically Alloyed Nanopowders

Abstract

Due to their outstanding mechanical properties and soft magnetic characteristics, cobalt-based metallic glassy alloys have stimulated much interesting research. These metastable ferromagnetic materials possess very small magnetocrystalline anisotropy, and almost zero magnetostriction. They reveal low coercivity, extremely low core loss, moderate saturation polarization, and very high magnetism. Despite these attractive physical behaviors, Co-based metallic glasses are difficult to obtain by the melting/casting and conventional rapid solidification techniques due to their poor glass-forming ability. In the present study, we succeed in preparing (Co75Ti25)100−xFex (x; 0–20 at.%) metallic glassy powders, using a mechanical alloying approach. The end product of the as-prepared powders was consolidated into full dense cylinders with large-diameter and thickness (2 × 2 cm), using spark plasma sintering technique. The results have shown that the consolidation step did not lead to any undesired crystallizations or phase transformations, and the as-consolidated buttons maintained their unique short-range order structure. These bulk metallic glassy systems possessed high glass-transition and crystallization temperatures, suggesting their high thermal stability. However, they showed low values of the reduced glass-transition temperatures, indicating that this system is difficult to prepare by the conventional way of preparations.

Effects of axial pressure on the evolution of core–shell heterogeneous structures and magnetic properties of Fe–Si soft magnetic powder cores during hot-press sintering

“…During HPS, axial pressure is applied to the SMPCs, which promotes the diffusion of atoms into the material, strengthens the dynamic conditions of sintering, increases the heating rate and shortens the sintering time. 17 The sintering heat required to prepare SMPCs from Fe–Si@SiO 2 core–shell heterostructure composite powders depends on the thermal energy between the Fe–Si alloy powders and that absorbed by the Fe–Si alloy. The superposition of the two thermal effects at the heterogeneous interface generates a local high temperature on the surface of the Fe–Si alloy powders and forms a gradient temperature field in the powders, 18 which decreases from the surface to the interior.…”

Mechanical Milling: A Superior Nanotechnological Tool for Fabrication of Nanocrystalline and Nanocomposite Materials

“…Over the last few decades, materials scientists’ research has enabled us to produce a diverse spectrum of complex materials utilizing innovative preparation processes. The fabrication techniques for advanced materials can be broadly classified as follows: Mechanically aided approaches include the following: (1) mechanically driven solid-state reaction approaches; (2) thermally assisted approaches; (3) mechanically assisted approaches; (4) chemically assisted approaches; (5) lithographic approaches; (6) vapor deposition approaches; and (7) liquid-phase fabrication approaches [ 6 ]. Ball milling, rapid solidification, atomization, sputtering, chemical vapor deposition, electron beam physical vapor deposition, arc discharge, laser ablation, photolithography, nano-imprint lithography, sol-gel, atomic force microscope nanostencil, plasma enhanced chemical vapor deposition, plasma enhanced chemical vapor deposition, and atomic layer deposition are some examples of the preparation methods that are used to fabricate new materials [ 1 ].…”

Microstructure Development and Properties of the Two-Component Melt-Spun Ni55Fe20Cu5P10B10 Alloy at Elevated Temperatures

“…There are reports on the production of amorphous-amorphous and amorphous-crystalline materials [ 1 , 2 , 3 , 4 , 5 , 6 ] and works on controlling the phase composition and properties of these materials [ 7 , 8 , 9 , 10 ]. Among the methods of producing amorphous composites, technologies based on the production of powders and their amorphization are also used [ 11 , 12 , 13 , 14 ]. They require precursor alloys with liquid supercooled range T g –T x .…”