Radiation response of inconel-Cu multimetallic layered composites: Role of alloy chemistry

The reliability and longevity of fusion reactors' current drive systems are essential for sustained operation under high neutron fluence, requiring materials that maintain high strength and conductivity while resisting high irradiation doses. Here, we investigate the stability and structural integrity of under irradiation using Molecular Dynamics simulations. The mechanochemistry of the constituent elements and their role in the radiation resistance is investigated by considering five variants of Inconel, i.e., Incoloy 800H (Ni₃₂Cr₂₁Fe₄₇), Inconel 625 (Ni₇₂Cr₂₃Fe₅), Inconel 690 (Ni₅₈Cr₃₁Fe₁₁), Inconel 718 (Ni₅₅Cr₂₁Fe₂₄), and Inconel X-750 (Ni₇₇Cr₁₄Fe₉). We revealed three linear, exponential, and plateau stages in the relationship between Frenkel Pair (FP) defect density and radiation damage. Furthermore, our results indicate a high Fe concentration reduces diffusivity between the two metallic layers, while a high concentration of Cr, with its low migration energy barrier, increases diffusivity. Among considered composites, the Incoloy 800H (Ni₃₂Cr₂₁Fe₄₇) shows the highest radiation resistance. FP defect clustering planes are revealed in both Inconel and Cu, while the formation of Stacking Faults (SF) and Lomer-Cottrell (LC) locks are also observed on the Inconel side; we revealed that the shear stress determines the orientation of the FP defect clustering planes.