Effects of yttrium on the formation and magnetic properties of bulk metallic glassy （Fe, Co）-B-Si-Nb alloys

The bulk metallic glassy （BMG） rods of [（Fe0.5Co0.5）0.72B0.192Si0.048Nb0.04]100-xYx （x=0-6） and [（FexCO1-x）0.72B0.192Si0.048Nb0.04]96Y4 （x=0.5-0.8） were prepared by copper mold casting. The structure, thermal stability, and magnetic properties of the samples were studied by X-ray diffraction （XRD）, differential scanning calorimetry （DSC）, and vibrating sample magnetometer （VSM）. Adding 1 at% to 6at% of yttrium, the bulk glassy alloy rods of [（Fe0.5Co0.5）0.72B0.192Si0.048Nb0.04]100-xYx （x=0-6） with the diameter of 3 mm were not formed, and the sample with 4at% of yttrium showed less crystalline phase than others. When the Fe/Co atomic ratio was between 5：5 and 7：3, the bulk glassy alloy rods of [（Fe1-xCox）0.72B0.192Si0.048Nb0.04]96Y4 （x=0.5-0.8） with the diameter of 2 mm were fabricated. In the （Fe, Co）-B-Si-Nb-Y BMGs, when the Fe content increased, the thermal stability, the supercooled liquid region, and the glass-forming ability （GFA） decreased, but the saturation magnetization （Ms） increased.