Influence of microstructure on the oxidation behaviour of the Ni-based single crystal superalloy AM1 between 850 and 1050 °C in air
Résumé
The influence of the as-cast and fully heat-treated microstructures on the isothermal behaviour of the Ni-based
single crystal superalloy AM1 was investigated at 850-1050 ◦C. It appears that the kinetics transition regime is a
function of time, temperature and also of bulk microstructure. The various characterisation techniques allowed
elucidating that the growth of a continuous inner layer of α-Al2O3 governs the oxidation mechanisms, irre-
spective of the microstructure. Such layer is favoured for high oxidation temperatures, long exposure times and
high γ’ precipitate surface fraction. However, the chemical segregation of the as-cast state is responsible for the
growth of inhomogeneous oxide layers