Temperature dependence of superstructure and fundamental reflections: study of a creep deformed single crystal nickel base superalloy AM1

High-energy X-ray synchrotron radiation was used to measure internal strains inside the bulk of creep deformed AM1 single crystal superalloy specimen. A sample creep deformed at 1050 °C with γ′ raft-like precipitates was studied ‘in situ’ in temperature. The superstructure reflections (100) and (001) as well as fundamental reflections (200) and (002) were measured up to the temperature of deformation using a high-resolution triple crystal diffractometer. The lattice parameter distribution which is related to internal stress distribution was determined for each phase in parallel and perpendicularly to the rafts. It was shown that these parameters depend strongly on the thermomechanical history of the analysed material and on the temperature at which measurement is performed.