Search

UDC 535.21:678.067 In studying the reaction of laser radiation with composite materials, it is important to determine the absorption factors, threshold of decomposition, and loss of mass of the materials investigated. A theoretical model which allows estimating these values for some composite materials based on a polyethylene matrix with different powdered fillers (Table 1) with a particle diameter of 1-20 #m is described in the present article. The results of the calculations are compared with the experimental data obtained in [1, 2]. The experimental values of the factors ,Uexpt and Rexpt from [1], obtained for radiation intensities of I 0 < 0.01 MW/cm 2 for a neodymium laser with a pulse duration of 2 msec, are reported in Table 1. Macroscopic decomposition of the materials begins, the reflection factor R decreases, the absorption factor ~ increases (by tens of times for some materials), and a crater forms on the irradiated surface of the samples with a further increase in I o. The dependences of the depth of the craters formed and specific loss of mass on the intensity of the laser radiation are reported in [2]. The proposed model of decomposition of composite material is based on the experimental data which show that absorption of radiation in the bulk of the Samples studied basically takes place on filler particles, whose heating causes decomposition of the surrounding polyethylene matrix. In this case, it is possible to estimate the dimensional absorption factor in the Bouguer--Lambert law in terms of the section cr (m 2) of absorption of light by the particles and their concentration N (m -3) in the material: = oN. (1)