Determination of hot deformation behavior and processing maps of IN 028 alloy using isothermal hot compression test

The deformation behavior of IN 028 alloy in the temperature range of 950–1150 °C and strain rate range of 0.01–30 s−1 has been studied using processing maps by isothermal hot compression tests. The power dissipation efficiency and instability parameter were evaluated with temperature and stain rate. The power dissipation map reveals that two domains of fine dynamic recrystallization (DRX) exist at the (i) temperature 950–1050 °C and strain rate 0.01 s−1 with its peak efficiency of 50%; (ii) temperature 1150 °C and strain rate 1 s−1 with its peak efficiency of 36%, with activation energy of 150 kJ/mol. The instability domain of flow behavior can also be recognized at the strain rate more than 1 s−1 at lower temperature and strain rate more than 10 s−1 at high temperature. The optimum hot working conditions for the superalloy IN 028 are suggested based on the processing map. The characteristic microstructures predicted from the processing map agreed well with the results of microstructural observations.