Abstract: Due to the significant differences in physicochemical properties such as melting point, thermal expansion coefficient, and crystal structure between aluminum and iron-including, thermal stress concentration is prone to occur during the welding process and brittle intermetallic compounds are formed, which leads to defects such as cracks and holes at the welded joints. While thermal aging duration can mitigate such defects, its impact on the reliability of joints remains further study. By using the molecular dynamics method, the atomic diffusion behavior of iron-aluminum electromagnetic pulse welding joints at different temperatures (120, 150, 180, 210 ℃) and different thermal cycle times (0, 5, 10 times) is simulated, and and the influence of thermal aging on the growth and evolution of interface defects is analyzed. The results demonstrate that at a temperature of 150 ℃, thermal aging is most conducive to the gradual healing of interface defects after electromagnetic pulse welding of aluminum-iron. At 120 ℃, interface defects are difficult to be effectively repaired due to insufficient atomic diffusion. The elevated temperatures (to 180 ℃ and 210 ℃) intensify atomic thermal motion, leading to the interface defect not only failed to heal but also developed a larger gap. Thermal cycling experiments reveal that at both 150 ℃ and 210 ℃, the mechanical properties of the joints are the strongest after five thermal cycles. This is because thermal cycling can promote interfacial atomic diffusion, thereby improving the mechanical properties of the joints.