Reverse bulging and plugging in metal foil induced by high power laser

摘要

In the last two decades, a great deal of attention has been paid to the interaction of high power laser with material in the fields of structural damage and laser processing [1-4]. The damage modes which may be spallation, melting and/or vaporization depend on laser parameters, for example laser power, laser beam diameter and pulse duration. There is the potential for failure by thermal stress for CW (continuous wave) laser intensities in the order of 10~3 W/cm~2 [5]. The damage may occur by melting and/or vaporization for laser intensities in the order of 10~5-10~8 W/cm~2 and for pulse durations in the order of milliseconds [6]. In this case, the thermal stress concentrated around the crater plays an important role in material and/or structure damage. The formation of plasma may generate shock waves propagating into the materials for laser intensity in the order of 10~8-10~(10) W/cm~2 and for pulse durations in the order of nanoseconds. When wave reflection takes place between two surfaces, there is the potential for failure by spallation [7].