Initial oxidation behavior of a single crystal superalloy during stress at 1150 °C.

ABSTRACT

Revealing the initial oxidation behavior of single crystal superalloys is significant for a better understanding of the oxidation mechanism of turbine blades during service condition. The purpose of current research was to observe the initial oxidation of a single crystal superalloy. In-situ oxidation experiment during only thermal exposure and thermal-stress pattern were carried out. The mechanism of nucleation and growth of oxide scale was discussed. Results showed that the oxide on the interface of γ/γ' phase was constituted of Al2O3 precipitates and formed by external diffusion of Al atoms or ions. Loading stress enhanced the diffusion of Al atom causing high oxidation rate. A logarithmic model was proposed and fitted well with the oxidation process.