Measurement and analysis of energy absorptivity during laser perforation of iron plates using a water-cooled...

To investigate the energy deposition process during high-power laser perforation of iron plates, experiments were conducted using a uniform laser spot to irradiate iron plates of varying thicknesses (1-3 mm). A water-cooled integrating sphere was employed to measure the reflectivity of 400-2000 W laser beams during the perforation process. By combining reflectivity and transmittance measurements, the absorptivity changes of the iron plates before, during, and after perforation were determined, along with data on perforation time and area. Before perforation, the absorptivity of the iron plate increased rapidly due to surface oxidation, followed by a gradual decline. At the moment of perforation, the absorptivity curve exhibited a discontinuity, influenced by the initial perforation area. After perforation, absorptivity varied with changes in the perforation area. While the absorptivity trends for iron plates of different thicknesses under varying laser powers were similar, their numerical values differed. A theoretical model was developed to calculate the absorptivity changes for a 1 mm iron plate, with results aligning well with experimental data. This study addresses key challenges in measuring, modeling, and calculating energy deposition during and after laser perforation of metals, providing valuable insights for understanding the physical processes, experimental measurements and modeling of high-power laser-metal interactions.