Accelerated High-Temperature Creep Failure Induced by Internal Nitridation of In617 Superalloy

Abstract

Internal nitridation behavior was investigated in high-temperature creep experiments of IN617 superalloy. The results exhibited that nitrogen in air influenced microstructure significantly and deteriorated creep life to the level far below the fitting Larson-Miller curve. As compared to oxidation that occurred on the surface, nitridation could penetrate into interior regions of IN617. Furthermore, substantial nitrides, including π phase, AlN, Cr2N and (Ti,Cr)N, were found to precipitate in IN617 with different morphologies and orientations. The formation of plentiful brittle π phase and AlN in high-temperature duration was dominantly responsible for creep property deterioration.

Keywords: Internal nitridation, Superalloy, IN617, creep, Precipitation, Nanoindentation