The Local Microscale Reverse Deformation of Metallic Material under Laser Shock

A striking phenomenon is found that local plastic deformations, with an opposite direction to the external force, applied on metallic target surface under a given laser shock condition. Laser shock treatment is carried out on a number of metallic materials, and the surface topographies after laser shock treatment are observed via White Light Interferometer (WLI) measurement. The results show that many surface relief structures with irregular shapes and random distributions appear on target surfaces under the action of invisible shock waves. It personifies the real plastic flow behavior of metallic materials suffer to pressure waves, and the local reverse deformation.