Research on thermal and mechanical effects of Al/PTFE reactive materials irradiated by femtosecond pulsed laser

Abstract In order to study the temperature distribution and thermal stress of femtosecond pulsed laser interacting with energetic materials, in this paper, a femtosecond pulse laser loading system combined with an infrared thermal imager was used to experimentally study the temperature of the material when the femtosecond pulse laser irradiated Al/PTFE reactive material. Scanning electron microscope (SEM) was used to analyze the ablation morphology of laser ablated Al/PTFE. The theoretical model of the interaction between laser and Al/PTFE reactive material was established and the numerical calculation was carried out. The thermal stress was calculated and analyzed by using the material temperature measured by the experiment according to the thermoelastic theory. The following conclusions are obtained. The material is melted and vaporized under laser irradiation and ablation marks appear. The material temperature and ablation depth in the experiment and numerical simulation have a certain consistency. The heat released by the exothermic reaction in the laser irradiation area of the material has little effect on the surrounding materials. The radial thermal stress generated during laser irradiation is compressive stress, and the circular stress along the radius of the light spot changes from compressive stress to tensile stress. The greater the laser repetition frequency and the longer the laser action time are, the greater the thermal stress is. The maximum radial compression stresses are 2.54 MPa and 4.52 MPa when the laser repetition frequencies are 500 Hz and 1000 Hz, respectively.