Abstract

A very thick (∼1 mm) coating of Fe-based amorphous material was applied to a Q235 steel substrate by detonation spraying. The rate-dependent anelastic and viscoplastic deformations of the coating were investigated through nanoindentation creep experiments with loading rates of 0.1∼5 mN s−1; the results were analyzed using the Maxwell-Voigt model with two Kelvin units. Creep deformation in the Fe-based amorphous coating was found to be sensitive to loading rate; the nanohardness, creep-stress exponent, and viscosity lessened with increased loading rate during viscoplastic deformation. The presence of two characteristic peaks in the relaxation-time spectrum shows that the anelastic deformation was related to the activation of two types of defects. Low loading rates promoted the activation of defects in the soft region with long relaxation times; larger loading rates promoted the activation of defects in the hard region with shorter structural relaxation times, allowing plastic deformation. This resulted in lower creep resistance at higher loading rates.

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