Features and Usefulness of High-Order Multicomponent Glassy Alloys

Seminar by Professor Akihisa Inoue on Thursday 12 July at 12:15 in Goldsmiths 1 Lecture room.Professor Inoue, is a world-leading material scientist and a pioneer in the development of Bulk Metallic Glasses and Advanced Non-Equilibrium Materials. Former President of Tohoku University, Japan he currently serves as a Special Advisor to the Chancellor and as the Director of the International Institute for Green Materials, Josai University Educational Corporation in Tokyo, Japan. Professor Inoue has received significant recognition for his contribution to Materials Science and Engineering. He is a member of Japan Academy, a foreign member of the US National Academy of Engineering and an Honorary Member of the Indian Materials Research Society. He received numerous awards including the Japan Academy Prize, the James C. McGroddy Prize for New Materials awarded by the American Physical Society, the Japan Prime Minister’s Prize, the Kelly Lecture of University of Cambridge, the Morris Traverse Lecture of the Indian Institute of Science in Bangalore and the Acta Materiallia Gold Medal.Talk by Professor Akihisa Inoue

Features and Usefulness of High-Order Multicomponent Glassy Alloys

Akihisa Inoue1-4

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.