Preparation and properties of quaternary CoMoPB bulk metallic glasses

A new series of Co80-xMoxP14B6 (x = 7, 9, and 11 at%) bulk glassy alloys were successfully prepared by a combination method of fluxing treatment and J-quenching technique. The glass-forming ability (GFA) of the obtained Co-based alloys is sensitive to the Mo content substituted for Co, and the maximum attainable diameter for a fully amorphous state can reach 4.5 mm at x = 9. The compressive tests show that the obtained Co-based BMGs exhibit a compressive strength of 3.3-3.9 GPa, but nearly zero compressive plasticity. The new Co-based BMGs possess good soft magnetic properties, and their saturated magnetization values decrease from 47 emu/g (0.45 T) to 14 emu/g (0.14 T) with increasing the content of the Co substitute from 7 at% to 11 at%, which may be attributed to the anti-ferromagnetic coupling between the Mo and Co atoms. Because of their good GFA, high Co content, few constituting elements, and relatively high strength, the obtained Co-based BMGs (especially Co71Mo9P14B6 BMG) can be considered promising as starting alloys to develop the new Co-based BMGs for the advanced structural and functional applications. (C) 2015 Elsevier Ltd. All rights reserved.