光斑尺寸对连续激光辐照铝合金温度响应影响研究

In order to investigate the temperature response and thermal damage of a 6061 aluminum alloy after variations in spot size of continuous laser irradiation, a three-dimensional physical model under laser irradiation was established based on ANSYS finite element software. First, we used different laser parameters to carry out laser irradiation experiments, and then, based on the collected temperature and front surface scattered light intensity data, we calculated the dynamic changes in the absorptivity of the target during laser irradiation. Finally, the optimized model was used to analyze the temperature rise characteristics of the target irradiated by lasers at different spot sizes. The research results show that the absorption rate of the material increases with an increase in temperature under 1000 W/cm² laser irradiation. Due to the localized characteristics of laser loading, lateral thermal diffusion affects the longitudinal temperature rise, and its effect becomes smaller when the spot is larger, as related with the alloy's thermal diffusion length. For the 6061 aluminum alloy material with a thickness of 4 mm, when the spot size is greater than 10 cm, the effect of the spot's size is negligible, and the time threshold of fusion damage on the back surface of the target remains unchanged at 2.6 s.