Study of the Tensile and Fatigue Properties of Quinary Strengthening Phase in Ni-Based Superalloys

The embedded atom method potential for the Ni–Al–Co–Ti–Cr quinary alloy is established using the lattice inversion method, confirming that this potential accurately captures the static physical properties of the multielement alloy. The mechanical behavior of the DZ411 alloy at high temperatures is simulated through molecular dynamics, focusing on its tensile strength and fatigue properties. The high-temperature tensile simulations show that as temperature increases, the interatomic forces weaken and the dislocation density significantly decreases, leading to a notable drop of ultimate tensile strength. Fatigue tests conducted at various temperatures for 15 cycles reveal that at room temperature, the internal structure gradually deteriorates under repeated loading, reducing its tensile strength. At high temperatures, due to the predominance of elastic deformation, the mechanical properties exhibit minimal variance before and after loading. During the compression process, the alloy exhibits characteristics of the face-cubic-centered structure and formed hexagonal-close-packed structure on the (111) crystal plane, which ensures that the stress–strain curve maintains a consistent shape throughout the compression process. This work deepens the understanding of the mechanical performance changes of the DZ411 alloy under extreme conditions, providing theoretical guidance for the performance optimization of high-temperature alloys.