TY - JOUR A1 - Agudo Jácome, Leonardo A1 - Göbenli, G. A1 - Eggeler, G. A2 - Göken, M. T1 - Transmission electron microscopy study of the microstructural evolution during high-temperature and low-stress (011) [01-1] shear creep deformation of the superalloy single crystal LEK 94 T2 - Journal of Materials Research N2 - The present work describes the shear creep behavior of the superalloy LEK 94 at temperatures between 980 and 1050 °C and shear stresses between 50 and 140 MPa for loading on the macroscopic crystallographic shear system (MCSS) (011)[01-1]. The strain rate versus strain curves show short primary and extended secondary creep regimes. We find an apparent activation energy for creep of Qapp = 466 kJ/mol and a Norton-law stress exponent of n = 6. With scanning transmission electron microscopy, we characterize three material states that differ in temperature, applied stress, and accumulated strain/time. Rafting develops perpendicular to the maximum principal stress direction, gamma channels fill with dislocations, superdislocations cut gamma' particles, and dislocation networks form at gamma/gamma' interfaces. Our findings are in agreement with previous results for high-temperature and low-stress [001] and [110] tensile creep testing, and for shear creep testing of the superalloys CMSX-4 and CMSX-6 on the MCSSs (111)[01-1] and (001)[100]. The parameters that characterize the evolving gamma/gamma' microstructure and the evolving dislocation substructures depend on creep temperature, stress, strain, and time. PB - Cambridge University Press CY - Cambrigde KW - Dislocations KW - Microstructure KW - Scanning transmission electron microscopy (STEM) KW - Creep KW - Shear test PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/43756 AN - OPUS4-43756 SN - 0884-2914 SN - 2044-5326 VL - 32 IS - 24 SP - 4491 EP - 4502 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany