Fe-B-Si-Nb bulk metallic glasses with high strength above 4000 MPa and distinct plastic elongation

The glass-forming ability and mechanical properties of Fe-B-Si-Nb glassy alloys have been investigated. The Fe72B20Si4Nb4 glassy alloy was prepared in a cylindrical form with a diameter of 2 mm. Young's modulus, compressive fracture strength and plastic elongation of the bulk metallic glass were 200 GPa. 4200 MPa and 1.9%, respectively. Many shear bands were observed along the shear plane, which was declined by about 43 degrees to the direction of applied load, and the fracture occurred along the shear plane. The local-ordered regions were recognized in the high-resolution TEM image of the Fe72B20Si4Nb4 bulk metallic glass with a diameter of 2 mm. The good mechanical properties are attributed to the suppression effect of the local-ordered regions on the propagation of shear bands.