An example of thermodynamical calculations applied to the study of the high temperature behaviour of Co-base superalloys strengthened by tantalum carbides

Overview & Synopsis

Cobalt-base superalloys are currently used as bulk materials for parts of aeronautic turbines. These latter support mechanical and thermal constraints. As the lifetime of these parts is limited, the aim of this work is to elaborate new alloys with higher solidus temperature and mechanical resistance. The best way to speed up development of new materials is thanks to thermodynamic simulations (Thermo-Calc), which will propose solutions to choose the microstructure and the alloy elaboration process. In our research fields, thermodynamic simulations allow: * the prediction of the equilibrium phases - to better select the chemical composition in order to obtained the desired phases (natures and quantities) - to prevent the risk of apparition of undesirable phases (s phase, TCP phases….) * the selection of highest refractory materials - to select an alloy with the solidus temperature as far as possible of the working temperature. * the evaluation of local melting temperature - to predict a possible minimizing of surface mechanical properties induced by the oxidation phenomena.