Investigation of Flow Instability in High Temperature Deformation of INCONEL Alloy 783 Using Processing Map Approach

The high temperature deformation behavior and flow instabilities of Ni-Fe-Co base superalloy, INCONEL alloy 783 during hot working process were investigated with process maps consisting of a power dissipation of dynamic materials model (DMM) and various flow instability criteria. In order to establish the processing map of INCONEL alloy 783, hot compression tests were carried out under different temperature and strain rate conditions, with true strain up to 0.7. On the basis of the comparison between processing maps and microstructural analysis, the reliability of various flow instability criteria was estimated. Finally the useful instability criterion for predicting the forming defects was suggested through the compression test results and experimental observations of actual ring rolling process of INCONEL alloy 783.