Influence of microstructure on local intra- and intergranular deformations during creep of a nickel-based superalloy at 700°C

Several microstructural parameters of the NR6 nickel-based superalloy were varied by applying four heat treatment procedures. Tensile creep tests were performed in air at 700°C and 700MPa on specimens exhibiting different grain sizes, strengthening γ′ precipitate sizes and distributions and grain boundary morphologies. Flat creep specimens were instrumented thanks to a dedicated microextensometry technique to analyze the local intra- and …