A unified damage-healing model for laser shock repair of copper film

A healing method for fatigue damage was studied by laser shock peening (LSP) with excimer laser for polycrystalline copper film. It is found that the reduction of plastic strain range due to laser shock peening could be responsible in the improvement of residual fatigue lives for the damaged specimens by LSP, and the degree of reduction in plastic strain range for the damaged specimens by LSP is more evident when the stress range is larger. According to the variation of the fatigue ductility of the specimen before and after LSP, a unified damage-healing model is proposed during the damage-healing process for copper specimens. The predicted lives by the proposed method agree well with the experimental results.