MODEL FOR PREDICTION OF HIGH TEMPERATURE DURABILITY OF CASTABLE NICKEL-BASE SUPERALLOYS

The relationship between the long-term strength and the structural-phase and physico-chemical parameters of castable polycrystalline nickel-based superalloys is considered. A regression model for prediction of the durability at a temperature of 1100 °C and a stress of 80 MPa of the considered class of alloys is proposed. The model takes into account the amount of the γ'-phase, the γ'-solvus and solidus temperatures, γ/γ'-misfit, the lattice spacing of the γ- and γ'-phases, and the atomic mass of the alloy. The reliability of the durability prediction is confirmed by comparison with the experimental results on the long-term strength at temperatures 1000, 1050 and 1100 °C of a number of industrial and experimental castable polycrystalline nickel-based superalloys.