Corrosion behaviour of nickel-chromium based super-alloys Inconel 738 and Inconel 713 after exposure to impure He

摘要

Inconel 738 and Inconel 713 are nickel-chromium super-alloys used for high-temperature applications, especially for gas turbines. These alloys are also considered as structural materials for some components of advanced gas cooled nuclear reactors. The use of resistant materials and knowledge about their behavior during operation are an important precondition for ensuring the safety and reliability of energy facilities. The comparison of the initial and exposed states of both super-alloys was done. The materials were exposed in the High Temperature Helium Loop to impure helium environment at 770 °C and 5 MPa for 1000 hours. The microstructure changes and corrosion product layers after exposure were evaluated by means of light optical and scanning electron microscopy. After exposure the microstructure changes were observed, as Cr rich phase and Ti and Cr depleted zone. The corrosion layer thickness in dozens of micrometers was measured.