EXPERIMENTAL CAST NICKEL SUPERALLOYS AND GAMMA-PRIME ALLOYS FOR HIGH TEMPERATURE APPLICATIONS IN GAS TURBINES.

Abstract

The relationships between the constitution, microstructure and selected mechanical properties of creep-resistant cast nickel alloys have been explored. Among the experimental alloys two, designated R6 and R8, have excellent high temperature creep strength. structural stability, thermal shock resistance and hot corrosion resistance. Metallurgical observations on the factors governing the strength of these alloys suggested that the solvus temperature of the gamma prime precipitate and the alloy hardness could be related with creep-rupture properties. The information from the phase equilibria studies was used as a basis for developing gamma-prime base alloys that also combine good mechanical properties with very good oxidation resistance.