Effect of unconstraint vibration treatment on fatigue damage healing for copper film

A novel approach to heal fatigue damage for copper film by unconstraint vibration was proposed in this paper. The microscope observation for copper film under various conditions was conducted on exactly the same area by electron backscatter diffraction (EBSD) method. The results found that the fraction of the low angle grain boundaries (LAGBs), the dislocation density, the stored strain energy, and the grain orientation can be restored to the original state after the unconstraint vibration treatment. The plastic strain energy generated in the damage process for the copper film before and after the treatment was analyzed. It was found that the increased plastic strain energy of the specimen after treatment is approximately equal to the consumed plastic strain energy of the specimen before treatment. The fatigue-healing experimental results showed that the fatigue crack initiation life is about 2.6 times that of no treatment.