TY - CONF A1 - Agudo Jácome, Leonardo T1 - Dislocation analysis in Ni-base superalloy single crystals N2 - The LEK94 is a Ni-base superalloy single crystal (SX) of the second generation, a materials class which is important for its high temperature creep resistance (>1000°C) in first stage blades of low-to-medium pressure gas turbines. Monocrystalline Ni-base superalloy SXs have a two-phase microstructure consisting of small cubes (' phase with the ordered L12 crystal structure, cube edge length: 500 nm), separated by thin channels (γ phase with fcc solid solution structure, channel width: 20 nm). The microstructural evolution during high temperature and low stress tensile creep has been thoroughly investigated previously, mainly for [001] loading, both in terms of dislocation activity (filling of γ channels, formation of dislocation networks, cutting of the γ’ phase) as well as phase coarsening (rafting, topological inversion). Other loading geometries have received less attention. The present work studies high temperature and low stress creep deformation of the superalloy LEK 94 at temperatures around 1000°C, where rafting occurs. Differences between loading under different uniaxial, biaxial and triaxial stress states are discussed. Stereo-microscopy and g∙b analysis in the scanning transmission electron microscopy mode (STEM) are combined for microstructural analysis. The focus is set on the role of dislocation interactions with the aging microstructure. Both development in STEM characterization methods, as well as the roles of phase coarsening, γ channel filling, microstructural heterogeneity and γ’ phase cutting are discussed. T2 - Eingeladener Vortrag CY - US Air Force Research Laboratories, Dayton, OH, USA DA - 19.07.2016 KW - Doslocation KW - Superalloy KW - Microscopy KW - Creep PY - 2016 AN - OPUS4-41945 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -