用波长为1.06μm、脉宽为23ns、功率密度为10^9W/cm^2级的短脉冲强激光冲击锻铝靶材。在靶材表面涂有保护物(黑漆)的情况下,损伤形式主要有层裂和剪切断裂;层裂与激光功率、靶材的力学性能和厚度等因素有关,它起源于微裂纹,但不全是单个微裂纹扩展的结果,在一定的条件下,层裂可以进行一次或多次,它属于韧性断裂。剪切断裂不同于激光切割,当约束孔径较小时,靶材在冲击波作用下常以剪切失效的形式出现。
The 6063 aluminum alloy specimen was shocked by pulsed laser with wavelength 1.06 μm, duration 23 ns and power density 109 W/cm^2 level. The results show that the damage of specimen coated with a protective layer of paint is spallation or shear fracture. The effect of spallation is related to power density of laser, mechanical behavior and thickness of specimen and so on. The spallation is originated from the microcracks but not all microcracks extended into spallation, and it can proceed once or more in the surface of target. The fractogragh indicates that it belongs to ductile fracture. Shearing fracture is different from laser cutting which employs the response of heat. When the size of hole of concave die is smaller and the power of laser is strong enough, the shearing damage always occurs. Due to the complicate mechanism of interaction between materials and intense laser, some mechanisms of damage need experimentally and theoretically further research.