| When |
Jul 12, 2018
from 12:15 AM to 01:00 PM |
|---|---|
| Where | Goldsmiths 1 |
| Attendees |
Professor A Lindsay Greer |
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Talk by Professor Akihisa Inoue
Features and Usefulness of High-Order Multicomponent Glassy Alloys
1International Institute of Green Materials, Josai International University, Togane, 283-8555, Japan
2School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
3Department of Physics, King Abdulaziz University, Jeddah, 22254, Saudi Arabia
4MISiS, National University of Science and Technology, 119049, Moscow, Russia
ABSTRACT
It is known that Fe-based glassy alloys and Zr-Al-Ni-Cu base bulk metallic glasses (BMGs) have gained significant application fields as functional and structural material parts in personal computer and smartphone etc. and attracted further increasing interest as novel engineering materials. By synthesizing a new type of glass-based structure alloys and improving fundamental properties and engineering characteristics of glassy alloys including BMGs, their engineering importance is expected to increase further in the near future. More recently, we have carried out the syntheses of high-order multicomponent Fe-, Zr- and Al-based glassy alloys with useful properties and reported the following results: In Fe-based alloys, (1) the successes in forming Fe-P-C-based BMGs with unprecedented plasticity as well as good soft magnetic and magnetocaloric properties, (2) new Fe-based soft magnetic glassy alloys with very high saturation magnetization above 1.9 T, low coercivity below 3 A/m, high effective permeability above 2 × 104 at 1 kHz and high Curie temperature, (3) development of Fe-TM-P-B-Si (TM=transition metal) base soft magnetic glassy alloys with magnetic characteristics exceeding those for commercial magnetic glassy alloys “Liqualloy” and “SENNTIX”, (4) pseudo-high entropy (PHE) Fe-based glassy alloys containing sub-nanoscale clusters with high strength and good ductility, (5) finding of ductilization phenomenon of nanostructure bcc-Fe + amorphous soft magnetic alloy ribbons by micro crack-induced softening mechanism, and (6) improvement effect of glass-forming ability of Fe-based BMGs in air and the oxygen-containing atmosphere. In Zr-based alloys, (1) synthesis of PHE clustered BMGs caused by easy nucleation and sluggish growth rate and their high thermal stability, (2) synthesis of new PHE BMGs and the clarification of the role of PHE component in the glass-forming ability, (3) formation of granular glassy structure due to immiscible element by casting process and its unique mechanical and crystallization behavior, (4) reversible changes in glass transition behavior, supercooled liquid region, atomic configurations and fundamental properties by controlling the ejection temperature of alloy liquid, and (5) development of a new type of biomedical BMGs. In Al-based alloys, (1) extension of Al + glassy phase field by choosing suitable multicomponent alloy systems, (2) novel reverse transformation phenomenon from metastable multicomponent compound to Al + amorphous phase upon heating, (3) proportional relation between the solute content in amorphous phase and hardness in a wide hardness range and synthesis of Al + amorphous phase alloys with ultrahigh hardness. This presentation aims to introduce a part of our recent results on new glass-based structure alloys with novel phenomenon and useful properties for Fe-, Zr- and Al-based high-order multicomponent alloys prepared by melt spinning and copper mold casting processes.
