Microstructure and performance of novel ductile FeNi-based metallic glasses

Abstract

Fe-based bulk metallic glasses (BMGs) are of significant interest because of their superior magnetic and mechanical properties, but the plastic strain deficiency at room temperature restricts their application. In the present study, the effect of Ni content on thermal stability, soft magnetic properties and compressive plastic deformation was investigated in Fe80−xNixP12B4.9Si2.5Cu0.6 (x = 0, 3, 6, 9, 12, 15) BMGs. We discovered that the Ni-bearing BMGs exhibit strong GFA, good soft magnetic and mechanical properties, and high Tc, while the excessive Ni addition causes performance deterioration. The Fe71Ni9P12B4.9Si2.5Cu0.6 bulk glass exhibits high strength of about 3000 MPa and elevated plastic strain of 5.1%, together with high saturation magnetic induction of 1.51 T and low coercivity of 1.8 A/m. The Curie temperature up to 636 K was an intriguing finding. X-ray photoelectron spectroscopy results suggest that the brittle-ductile transition comes from the more s-like bonds between clusters because of the Ni addition. In terms of the inherent elastic nature, we consider that the high Poisson's ratio and the low G/K ratio of Ni lead to a large effective volume of the shear transition zone, which corresponds to the nucleation of shear bands. The significant compressive plastic behavior, large GFA and good soft magnetic properties indicated that the current Fe-based BMGs are promising for structural and magnetic functional applications.