Impact of self-heating during hot deformation in the post-dynamic recrystallization and grain growth of an Fe-based superalloy

Abstract

Abstract. During hot working, strain rate, strain level and the temperature of deformation, and hence the Zener-Hollomon parameter, become the regulatory thermomechanical parameters of the resultant stored energy value and distribution. An accurate estimation of the aforementioned parameters is thus required to control microstructural homogeneity in the post-dynamic state, since stored energy value and distribution directly affects post-dynamic recrystallization and grain growth mechanisms. In order to do so, the self-heating phenomena that becomes significant at high strain rate hot deformation must be taken into consideration. In this work, several cylindrical samples of the A-286 alloy are submitted to hot compression tests performed in a Gleeble 3500 machine. The microstructure in the deformed-state is analyzed at the center, and the effect of the thermomechanical parameters of hot deformation on the resulting microstructure is discussed. In addition to this, the local thermomechanical testing conditions are estimated considering self-heating and local strain level and strain rate fields. Hence, the relationship between these newly estimated parameters and the microstructure can be assessed.