Preparation and properties of Fe_73-xNb₄Hf₃ Y_xB₂₀ bulk amorphous alloys

By micro-alloying technology, Fe-Hf-Nb-B-Y bulk amorphous alloys were prepared by copper mold casting method. The glass-forming ability (GFA), soft-magnetic and mechanical properties of these bulk amorphous alloys were characterized by X-ray diffractometry (XRD), differential scanning calorimeter (DSC), scanning electronic microscopy (SEM), vibrating sample magnetometry (VSM) and Instron type tester. The results show that a partial substitution of Fe by Y causes a significant improvement of the GFA of Fe-Hf-Nb-B-Y alloys. The maximal diameters for glass formation are 2 mm for Y-free alloy, 3 mm for 1%(molar fraction) Y alloy, 4 mm for 2% Y alloy and 3.5 mm for 3% Y alloy. The saturation magnetization, coercive force, elastic modulus, elastic strain and compressive fracture strength of Fe-Hf-Nb-B-Y bulk amorphous alloys are in the range of 1.10-1.25 T, 3-6 A/m, 184-206 GPa, 1.6%-2.0% and 3227-3484 MPa, respectively. Based on the experimental results, the effects of micro-alloying on GFA, soft-magnetic and mechanical properties of the alloy series were discussed.