Fe-Y-M-B (M = Nb or Ta) bulk metallic glasses with ultrahigh strength and good soft magnetic properties

The effect of partial replacement of Y with a fourth element (Nb or Ta) on the glass forming ability (GFA), mechanical, thermal and magnetic properties of ternary Fe-Y-B bulk metallic glasses (BMGs) was explored. GFA, thermal, magnetic and mechanical properties of BMGs with compositions Fe72Y6-xMxB22 (M being Nb or Ta, x = 1-5) were investigated. The partial replacement of Y by Nb or Ta greatly enhances the GFA to cast glassy rods with a diameter of at least 4 mm (Nb) or 3 mm (Ta) from the original 2 mm. They exhibited high saturation magnetization above 1.25 T and low coercivity below 20 A m-1. The Curie temperature and electrical resistivity are higher than 530 K and 190 μΩ cm, respectively. The Fe72Y4M2B22 (M = Ta or Nb) BMGs show ultrahigh compressive strength of 4150-4200 MPa. With lower content of Y, which is very reactive, and the combination of promising properties, these new BMGs have potential for industrial applications compared with the ternary Fe-Y-B BMGs