Insights into the ultrahigh glass-forming ability of the Fe-Co-Cr-Mo-C-B-Y alloy system from the electronic-structure perspective

School of Materials Science and Engineering, Harbin Institute of Technology - Harbin 150001, China

^(a) junshen@hit.edu.cn

Received: 1 April 2012
Accepted: 4 July 2012

Abstract

The effect of cobalt on the glass-forming ability (GFA) of Fe-Co-Cr-Mo-C-B-Y bulk metallic glasses has been investigated by using ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy. The alloy containing 7% Co (Co7 alloy) exhibits the highest binding energy and the minimum electronic density of states at the Fermi energy in the valence band spectrum and possesses the largest carbide and metal boride peak intensity in the C 1s and B 1s core-level spectrum. The origin of the ultrahigh GFA for the Co7 alloy has been discussed in terms of the unique electronic structures, which are closely related to the densest atomic packing, the smallest atomic clusters, the minimum electronic density of states at the Fermi energy, and the most numerous transition-metal–carbon and transition-metal–boron bonds.