强激光诱导冲击波的实验研究

Experimental study of high-power laser induced shock waves

为了提高利用激光冲击波改进材料性能的技术,采用响应快、测量范围大的绝缘膜组合式高聚物压电传感器和示波器对激光诱发的冲击波进行了研究。通过测量无约束层和有约束层时的压电波形,得出相应的激光冲击波波形并进行比较。结果表明,有约束层时激光冲击波的脉宽是激光脉冲宽度的3倍左右,峰值压力较无约束层时明显提高。激光冲击波在不锈钢材料中的平均传播速度为5.72×103m/s,与声波纵波的传播速度一致。

To improve the technology of modifying material properties by using laser induced shock waves ,the properties of laser shock waves were studied. The piezoelectric waves were measured using a polyvinylidene fluoride （ PVDF ） piezoelectric gauge of a short rise time and a wide linear response range ,together with an oscilloscope. Depending on the piezoelectric waves, laser-induced shock waves were measured. The laser-induced shock waves in the confinement geometry were analyzed and compared to that in the direct ablation regime. In the confined condition ,the FWHM of laser-induced shock wave was three times that of laser and the peak pressure was much higher than that in the direct ablation regime. The average propagation velocity of the laser-induced shock wave in stainless steel was 5.72 × 10^3m,/s.