Abstract
In this work, the evolution of the precipitation state of Alloy 617B at elevated temperatures and its consequent effects on the cyclic mechanical properties are studied for solution-annealed and stabilized material. To this end, specimens from both conditions were exposed to temperatures between 600 and 900 °C for times ranging from 3 hours to 1 year. Subsequently, the specimens were subjected to a complex cyclic loading at 700 °C. Additionally, TEM investigations were performed on the initial states and after thermal exposure at 700 °C for different times. In a next step a Chaboche type model was developed, containing a classical part describing the viscoplastic behavior and a metallurgical part taking into account the microstructure evolution at elevated temperatures. With the proposed macroscopic model, the observed material behavior can be described well for all present heat treatments with a unified set of model parameters.