Effect of single-pulse laser irradiation energy on healing fatigue damage for copper film

In this study, the optimum laser process parameter was determined by fatigue experiment for the treated copper film specimens with thickness of 25 μm. The mechanism of healing fatigue damage was analyzed by the numerical simulation of temperature field induced by laser irradiation and the microstructure changes on the surface of specimens. The results showed that the fatigue damage of copper film specimens can be healed when the applied energy density is in the range from 4×10 3 J/m 2 to 14×10 3 J/m 2 , and the fatigue life can increase by about 5 times when the applied energy density is 7×10 3 J/m 2 . The process hardening and grain refinement in the surface layer are mainly responsible for extending fatigue life.