Nanocrystallization enabled tensile ductility of Co-based amorphous microwires

Melt-extracted amorphous Co68.15Fe4.35Si12.25B15.25 microwires were drawn at ambient temperature into different diameters and the dependence of tensile properties and microstructural evolution on the degree of deformation was investigated. The cold-drawn wire with 51% area cross-section reduction exhibits a tensile ductility of 1.64%, with a tensile strength exceeding 4000 MPa. Deformation-induced Co-rich nanocrystals were observed in the cold-drawn wires and proved to be capable of arresting the quick extension of shear bands and leading to the enhanced global plasticity of the microwires.