Role of Ni and Co in tailoring magnetic and mechanical properties of Fe84Si2B13P1 metallic glass.

The disastrous annealing embrittlement of Fe-based metallic glasses with excellent soft magnetic properties is a long-standing issue. In order to alleviate the annealing embrittlement without worsening the soft magnetic properties, ferromagnetic elements Co and Ni are introduced to the Fe 84 Si 2 B 13 P 1 metallic glasses. The microstructure, mechanical and magnetic properties are investigated by synchrotron diffraction, two-point bending test and magnetometry. It is found that, in contrast to Co, proper Ni substitution for Fe significantly optimizes the H c of Fe 84 Si 2 B 13 P 1 metallic glasses and keeps the B s at a high level. According to bending tests, the ductile-brittle transition temperature of the metallic glasses increases slightly with Ni substitution and decreases prominently with Co substitution. Ultimately, the ductile Fe 82 Ni 2 Si 2 B 13 P 1 metallic glasses with B s of 1.65 T and H c of 3.4 A/m have been successfully obtained. Macroscopically, the cheerful propensity to form well-distributed shear bands during bending of Ni-substituted annealed alloys contributes to their good ductility. Furthermore, the alteration of ductile-brittle transition temperature can be conducted by the structural change at the medium-range scale as revealed by the pair distribution function measurements. After annealing the compression at atomic scale ranging from 6 Å to 16 Å of Co-substituted metallic glasses may hinder the creation of well-distributed shear bands and give rise to the deterioration of bending ductility. This work provides a perspective to understand the ductile-brittle transition of metallic glasses from the atomic scale. • With proper substitution of Ni for Fe, H c of Fe 84 Si 2 B 13 P 1 alloys decreases and B s keeps at a high level. • The bending ductility of annealed ribbons improves by Ni substitution. • The Ni-substituted alloys show good propensity to form well-distributed shear bands during bending. • Medium-range structure compression of Fe 78 Co 6 Si 2 B 13 P 1 alloy results in its ductility deterioration. [ABSTRACT FROM AUTHOR]