Evolution of dendritic microstructures in single crystal Ni-base superalloys: Crystal mosaicity. Low angle grain boundaries and Re-segregation (24/07/24)
Speaker and Affliation:
Professor Gunther Eggeler
Chair for Materials Science, Ruhr-University Bochum, Bochum (Germany)
When?
24th July, 2024 (Wednesday), 11.00 PM (India Standard Time)
Where
KPA Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract:
Single crystal Ni-base superalloys (SXs) exhibit excellent chemical and mechanical high temperature properties. They are used to make turbine blades for gas turbines which operate in aero engines and power plants at temperatures close to 1000°C. Cast SXs also exhibit a larger scale heterogeneity (> 100 µm scale) associated with the microstructural evolution during directional solidification, where dendrites form and grow. Single dendrites as well as groups with a small number of parallel dendrites are slightly misoriented with respect to their neighborhood. This leads to crystal mosaicity and the formation of low anlge grain boundaries (LAGBs). The contribution discusses competitive dendrite growth, the physical character of LAGBs and the segregation of Re to LAGBs.