Strength-hardness correlations of thermal-exposed oxide dispersion strengthened nickel-based superalloy with different grain size distributions

The determination of mechanical properties of oxide dispersion strengthened (ODS) nickel-based superalloys has certain challenges because of the irradiation and high-temperatures in nuclear industry. In this study, the microstructure and mechanical properties of ODS nickel-based superalloy with different grain size distributions were investigated using electron backscatter diffraction, transmission electron microscopy, tensile strength, and Vickers hardness. Besides, the correlation of hardness and yield strength was obtained using thermal-exposed samples. The results showed that the relationship between the hardness and yield strength mainly came from microstructure and anisotropy, especially the grain size distributions, the texture, and the tested plane. This allowed Vickers hardness tests rather than the tensile tests to evaluate the changes in strength, which is especially useful for the study of thermal stability of ODS nickel-based superalloys in nuclear industry.