Investigation of tensile Johnson-Cook model parameters for Nimonic 80A superalloy

Abstract

Developing high temperature technology increases the need for high temperature resistant materials. Nimonic 80A alloy is generally preferred due to its high creep resistance, oxidation resistance and high resistance to high temperature corrosion. The study determines the tensile constitutive equation (JC parameters) of Nimonic 80 A superalloys. Johnson Cook (JC) model is preferred amongst the various material constitutive equations (Zerille Armstrong, Bordner Partom, JC model). Three different kinds of tensile experiment were performed to identify the model parameters. These are quasi-static tensile experiments applied at room temperatures. These experiments were carried out at 0.001, 0.01 and 0.1 s−1 strain rates. Therefore, the reference strain rate for all experiments was selected to be 10−3. As a second test, tensile experiments were conducted at room temperature at high strain rates (102–103 s−1) using the Split Hopkinson pressure bar (SHPB). Lastly, tensile experiments were conducted at high temperatures (300–900 °C) at 0.001 s−1. It was observed whether all tests are compatible with each other or not, and so five Johnson-Cook (JC) parameters of Nimonic 80 A alloy were identified via the data found from the experiments. After determination of parameters, tensile test simulations by finite element method (FEM) were performed in ANSYS Workbench. As a result, the accuracy of the JC parameters is verified since there is a deviation of %2.84 between the experimental and the simulation results.