Enhanced glass forming ability and soft magnetic properties through an optimum Nb addition to a Fe-C-Si-B-P bulk metallic glass

Minor alloying effects of Nb on the thermal stability and magnetic properties of a ferromagnetic Fe75.5C7.0Si3.3B5.5P8.7 bulk metallic glass have been investigated. Through a proper replacement of Nb for Fe, glass forming ability of the alloy can be enhanced forming a fully amorphous rod with the diameter of 3 mm by a suction casting method. Precipitation of a primary carbide phase during solidification can be effectively suppressed by a small amount addition of Nb. Soft magnetic properties of the melt-spun ribbons can be improved by controlling crystallization procedure. Crystallization kinetics was analyzed by Jonhson-Mehl-Avrami equation using isothermally annealed ribbons for the foundation of the crystallization process control.