Development of a new alloy for directional solidification of large industrial gas turbine blades

Abstract

A nickel-base superalloy for directional solidification (DS) of industrial gas turbine blades was developed based on alloy IN792 with approximately 12 mass % Cr. From preliminary test results a temperature gain in stress-rupture strength of 30 K can be expected compared to Re-free aero engine alloys with columnar grains. This significant strength improvement can be achieved by adding 2 to 3 mass % Re in the group of 12 mass % Cr alloys. With balanced Cr-, Al-, and Ti- contents they also exhibit superior hot corrosion resistance compared to typical high Al / low Cr / low Ti aero engine alloys. The castability for large blades was proved.