Nanoindentation creep behavior of an Fe–Cr–Mo–B–C amorphous coating via atmospheric plasma spraying

Unlike crystalline alloys, disordered amorphous alloys lack long-range order. Even today, the creep mechanisms for amorphous alloys are far from being fully understood. In this work, an Fe–Cr–Mo–B–C (Cr: 25–27 wt%, Mo: 16–18 wt%, B: 2.0–2.2 wt%, and C: 2.0–2.5 wt%) amorphous coating was fabricated on the surface of a 304 stainless steel via atmospheric plasma spraying with a NiAl bonding layer. In this study, the effects of peak load and loading rate on the creep deformation behavior of the Fe-based amorphous coatings were investigated. The results demonstrated that a macroscopic viscous flow behavior was obtained at low peak loads, which led to a larger creep strain rate sensitivity m. At high loading rates, the accumulation of free volume led to an increase in the shear deformation zone and a more uniform plastic rheology. It indicated that at higher loading rates, the amorphous coating had higher m values under steady-state creep.