Tensile deformation dominated by matrix dislocations at intermediate temperatures revealed using in-situ EBSD in superalloys

The traditional view holds that the dominant deformation mechanism of Ni-based single crystal superalloys at intermediate temperatures (both in tension and creep) is stacking fault shearing γ’ phases. Here, we provide direct evidence to prove that the dominant deformation mechanisms of tension and creep are different. The orientation rotation path during tensile at 750 °C has been observed by in-situ electron back-scattered diffraction (EBSD). The result indicates that the dominant mechanism of tensile deformation at intermediate temperature is the movement of matrix dislocations, which is different from the dominant mechanism of the creep process, the stacking fault shearing γ’ phases.