Experimental characterization of flat indentation creep behaviour of Inconel 617

To analyse the creep deformation characteristics of Inconel 617, vacuum flat indentation creep test and microstructure analysis were completed in this study. With an increase in the creep load and temperature, limiting primary creep deflection and power law coefficient increased. An apparent indentation primary creep stage was observed and proven to be about 15–25 h in flat indentation creep test here. To describe the macro–deformation of Inconel 617, a modified theta–projection model was proposed and proven to be a feasible method to predict flat indentation creep curve accurately. Subsequently, a creep life prediction method based on deformation control was proposed. Based on the Larson – Miller parameter, reasonable conversion relationship between indentation creep stress and uniaxial creep equivalent stress was established. Finally, the microstructure analysis was completed to investigate the creep deformation characteristic. A hemispherical region along with significant extended grains and increase in hardness were observed. Considerable amount of Cr-rich precipitates and a small amount of Mo-rich precipitates were observed. Meanwhile, the precipitates were found to be discontinuous and granular for short indentation creep times.