Double-humped temperature dependence of plastic behaviour of K403 superalloy and its constitutive model

Abstract

ABSTRACT In this study, uniaxial compression experiments of K403 superalloy were conducted over temperature range of 298–1073 K and strain rate range of 0.1–5200/s. Temperature and strain rate effects on the flow stress were analysed. Double anomalous stress humps were noticed in the flow stress vs. temperature curves. The flow stress of the superalloy showed independence on strain rate over low strain rate range and an enormous increase with increasing strain rate over high strain rate range. Then, the effects of temperature and strain rate on the microstructure were observed and analysed. Due to the double-humped temperature dependence, the existing constitutive models were unable to accurately predict the plastic behaviour of K403 superalloy. Thus, a constitutive model was developed to describe the plastic behaviour of K403 superalloy. The model was able to capture the double-humped temperature dependence and anomalous strain rate dependence of plastic behaviour. It was shown that the plastic behaviour of the superalloy can be accurately predicted over a wide range of temperatures and strain rates.