|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Materials for High Temperature Applications: Next Generation Superalloys and Beyond
||Design of Nickel-base Superalloys with High Creep and Oxidation Resistance
||Franck Tancret, Edern Menou, Daniel Monceau, Gérard Ramstein, Pedro Rivera-Díaz-del-Castillo
|On-Site Speaker (Planned)
The resistance of nickel-base chromia-former superalloys to high temperature oxidation is critical in applications like gas turbines, power plants or chemical engineering. Usually, the nominal chromium content or the free Cr concentration in austenite is chosen to trigger the formation of a protective chromia layer. However, this is not sufficient since scale spallation and internal oxidation can occur. Exploiting both computational thermodynamics (Thermo-Calc CALPHAD software and related mobility data) and Gaussian processes models for the coefficient of thermal expansion (CTE) and for creep resistance, genetic algorithm multi-objective optimisation is used to (i) maximise Wagner’s criterion against internal oxidation by ensuring that chromium diffuses faster towards the surface to form the chromia scale than oxygen diffuses inwards, (ii) minimise CTE to lower thermal stresses between alloy and oxide scale, and (iii) maximise creep resistance. New superalloys with good creep and oxidation resistance are then designed for high temperature applications.