Wechselwirkung zwischen Mikrostruktur und Verformung der Legierung Alloy 617B - Experimente und Modelle

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.