Simulation of Thermo-mechanical Deformation Behavior and Lifetime of a Nickel-base Alloy

The thermo-mechanical deformation behavior of the Nickel-base alloy 602 CA is simulated by a viscoplastic material model by Chaboche. This model contains elastic properties, nonlinear isotropic and kinematic hardening and time-dependent material behavior. All material parameters for the complex superposition of simultaneously varying mechanical and thermal loadings are identified by isothermal complex low cycle fatigue (CLCF) tests at specific temperatures. These tests contain different strain amplitudes, strain rates and hold times. The parameters are obtained by computational optimization using a deterministic optimization technique (Levenberg-Marquardt algorithm). As a result, thermo-mechanical deformation behavior under various operating conditions can be predicted in terms of the generated stresses. The accuracy of the modeling is verified by corresponding experimental TMF testing. Furthermore, the lifetime of the Nickel-base alloy 602 CA is determined by using a mechanism-based model. The parameters of the model are identified by low cycle fatigue (LCF) tests.