Effect of Heat Treatment on Microstructure and Mechanical Properties of ODS Nickel-Based Superalloy via Strengthening Mechanism

The microstructure and mechanical properties of oxide-dispersion-strengthened nickel-based superalloy (ODSN) are related to its thermal stability and pose an essential challenge in modeling. This study focuses on the relationship between the microstructure and yield strength of heat-treated ODSN. Through a comprehensive description of the microstructure as investigated by electron-backscatter diffraction analysis and transmission electron microscopy, the contributions to the yield strength arising from various strengthening mechanisms in heat-treated ODSN specimens are addressed. The yield strength calculated using the characterized microstructure parameters in combination with different strengthening models are compared with the measured yield strength. This comparison reveals that grain-boundary strengthening, followed by dispersion and dislocation strengthening, is the significant contributor, while a root-sum-square superposition model reproduces the measured yield strength of heat-treated ODSN within the experimental scatter.