<p>During the rafting of single-crystal nickel-base superalloys, significant microstructural evolution occurs in both the <i>γ</i> and <i>γ</i>′ phases, leading to notable degradation in the fatigue and creep properties. Hence, it is essential to understand the evolution mechanisms of the microstructure during rafting process. In this work, the rafting behavior of the fourth-generation single-crystal nickel-base superalloy was investigated after thermomechanical fatigue combing scanning electron microscope and transmission electron microscope. In the early stage of rafting, different <i>γ</i>′ connection sites can lead to three modes, each resulting in different rafting rates. The differences in these modes are mainly related to the diversity of dislocation characteristics, which can influence the rafting kinetics by affecting the elemental diffusion rates. As the rafting process progresses, interface grooves form and exhibit various shapes, driven by the combined effects of gliding and climbing dislocation motions at the groove tips. This study reveals the microstructural evolution and the role of dislocations during different stages of rafting, providing valuable insights into controlling microstructure evolution and offering potential strategies for improving the fatigue performance of single-crystal nickel-base superalloys.</p> Graphical abstract <p></p>