Experimental studies of spallation in nanocrystalline copper film by laser irradiation
强激光辐照下纳米晶体铜薄膜层裂破坏的实验研究

The spall behavior of nanocrystalline copper film synthesized by electrodeposition technique is investigated by laser irradiation. The push-pull type VISAR with sub-nanosecond time resolution is used to measure the rear free surface velocity profile of the sample. The spall strength in nanocrystalline copper film is calculated from the measured free surface velocity profile as a function of tensile strain rate. Results show that the dynamic tensile strength of nanocrystalline copper film is about 3 GPa, which is much higher than that of polycrystalline bulk copper, but lower than that of single crystal copper. This difference may be attributed to the effective obstacles to dislocation motion by the presence or more grain boundaries in nanocrystalline copper.