Effects of Co substitution for Fe on the glass forming ability and properties of Fe80P13C7 bulk metallic glasses

• Fe80−xCoxP13C7 (x = 0–20 at.%) BMGs were prepared by fluxing and J-quenching techniques.
• The proper substitution of Co for Fe enhances the GFA of Fe80P13C7 alloy.
• The Co substitution for Fe reduces σf and then enhances εp of Fe80P13C7 BMGs.
• The Js first increase and then decrease with the Co content, and reach a maximum (1.55 T) for x = 5.
• The Tc of Fe80−xCoxP13C7 (x = 0–20 at.%) BMGs quickly increase with the Co substitution for Fe.

Bulk magnetic Fe80−xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) glassy alloy rods were prepared by the combination method of fluxing treatment and J-quenching technique, and the attainable maximum diameter for fully glass formation gets to 2.5 mm for x = 5. The effects of Co substitution for Fe on the glass formation ability (GFA), thermal stability, mechanical properties and magnetic properties have been investigated systematically. It was found that the partially substitution of Co for Fe can enhance the GFA of Fe80P13C7 alloy, while excessive substitution will lead to the degradation of GFA. The compressive test shows that the substitution of Co for Fe results in the decease of fracture strength, and then significantly enhance the room temperature plastic strain of the present Fe-based BMGs, which can be identified that the plastic strain at room temperature gets to 2.5% and 3.0% for x = 5 and 10, respectively. The saturation magnetization of Fe80−xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) BMGs firstly increases from 1.477 T to 1.550 T with increasing Co content from x = 0 to 5, and then deceases from 1.549 T to 1.519 T with increasing Co content from x = 5 to 20. The Curie temperature of the present FeCoPC BMGs quickly increases with the substitution of Co for Fe.