Mechanical properties and microstructural evolution of nickel-based superalloys

The mechanical properties and oxidation resistance of two nickel-based superalloys with and without oxide dispersion strengthened (ODS) phases at different temperatures were studied. The microstructure was investigated by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results show that the yield strength of the samples with and without ODS phases at room temperature is 1020 and 324 MPa, respectively. The yield strength model was constructed, and it is found that the contribution of grain boundary strengthening, dislocation strengthening and nanoparticle strengthening of nickel-based ODS superalloy exceeds 83%. As the temperature increases, grain boundary sliding and migration decrease the strength of sample but improve its ductility. Oxidation hinders the ductility of sample and intensifies its fracture, and the maximum elongation of nickel-based ODS superalloy at 800 °C is 47.3% .