Data supporting: Oxidation behaviour of single crystal nickel based superalloys: Intermediate temperature effects at 450-550oC

This data supports the following publication: Evangelou A., Soady K.A., Lockyer S., Gao N., Reed P.A.S.(2017), Oxidation behaviour of single crystal nickel based superalloys: Intermediate temperature effects at 450-550oC. Abstract: The oxidation behaviour of two commercially available single crystal nickel based superalloys has been investigated at the lower operating temperature range (450-550ºC) of an industrial gas turbine blade. Isothermal oxidation was carried out for varying times up to 640h and the low temperature exposure resulted in a sub-micron thick oxide. The external and internal oxide kinetics were studied via high resolution image analysis and both showed sub-parabolic growth rates. Thermogravimetric tests indicated that the overall oxidation growth obeys a near quartic power law while parabolic kinetics can describe the transient oxidation period. Characterisation of the resulting oxides was carried out using field emission gun scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Results from thermodynamic modelling (Thermo-Calc) of the oxide formation are also presented to further assess the postulated mechanism of low temperature oxidation in these nickel based superalloys.