Hot Deformation Behavior of Ni80A Superalloy During Non-Isothermal Side Pressing

In the present study, the microstructural changes of a Nickel based superalloy Nimonic
80A during a non-isothermal deformation were studied. Therefore, microstructure evolution during hot side pressing test was predicted with combined methods of finite element analysis and processing map of the material. The predicted results were validated through experimental microstructural studies. The results show that the distribution of deformation parameters (i.e. strain, strain rate, and temperature) is non-uniform in the deformed samples. The severity of this non-uniformity depends on the amount of sample reduction. High reduction value at one step forging can cause flow localization and non-uniform dynamic recrystallization, which results the formation of adiabatic shear bands, while using the lower reduction value at each forging step, leads to more uniformly distribution of the deformation parameters and thus uniform the dynamic recrystallization with the stable flow. Hence the workability and microstructure of the Nimonic 80A alloy are mainly depends on the deformation path.