Micromechanical Properties and Deformation Behavior of the Co70Fe3Mn3.5Mo1.5Si11B11 Amorphous Alloy

Abstract

This work reports an experimental study of the micromechanical properties of the Co70Fe3Mn3.5Mo1.5Si11B11 (at. %) amorphous alloy. All experiments were performed at room temperature on the unannealed sample in order to avoid the influence of thermally induced structural relaxation. X-ray diffraction confirmed the amorphous structure. Using nanoindentation tests, we determined key mechanical characteristics under a 20 mN load, including hardness, elastic and plastic deformation parameters, creep ratio, and other micromechanical properties. Scratch testing was performed under both static (20 mN) and dynamic (0.3–100 mN) regimes. We analyzed variations in penetration depth and residual depth during scratch testing. Surface morphology analysis after scratch testing confirmed no macroscopic crack formation or delamination. The friction coefficient behavior indicates sensitivity to localized contact loading and is consistent with localized deformation processes within the sample. A pronounced time-dependent deformation (CIT ~ 4.7%) under localized contact loading was also observed. The data were analyzed considering the structural state of the sample’s amorphous matrix and existing theories of plastic deformation mechanisms in amorphous systems. The ratio of elastic to plastic deformation, along with time-dependent deformation (creep), enables specification of the mechanical response of the investigated amorphous ribbon under localized microcontact loading. The obtained results provide qualitative insight into the deformation characteristics of unannealed amorphous ribbons.