不同能量毫秒激光与铝相互作用的温度计算
毕业论文关键词：毫秒激光，反冲压力，熔体喷溅，熔融深度
Title The calculation of the temperature of aluminum interact with millisecond laser of different energy.
Abstract The laser processing technology in the field of materials processing, has become an important processing manufacturing means with its unique superiority. The metal target was damaged by the lower power density pulsed laser in the way of melting and vaporizing. One of the most important aspects to research the interaction between the laser and metal is temperature field. It is of definite theoretical and practical significance to research temperature field interaction between the laser and metal on laser precision machining and laser ablation. According to the plastic yield, melting and the process of keyhole forming, we has carried on the theoretical calculation and experimental study. Separately, the temperature field of aluminum was simulated after irradiated by different wavelengths, different radius and different axial depth of laser. A semi-infinite ax symmetric model is established for millisecond laser melting of a metal slab. The analytical solutions of the entire temperature filed and the melting depth are obtained based on the heat conduction theory and the distribution of temperature field，and come to the conclusion that material surface temperature increases with the increase of laser power. It is shown that, for the absorbed laser intensities typical in welding and cutting, the recoil pressure induces high-velocity melt-flow ejection from the interaction zone. This melt flow carries away from the interaction zone a significant portion of the absorbed laser intensity. Thus, convection-related terms can be ignored neither in calculations of the energy balance in the interaction zone nor in calculations of the thermal field in the vicinity of the weld pool or cutting front. The research consequences may offer theoretical and experimental references to the further study of the temperature rising, the thermal stress, the plastic damage, the melting and the formation of hole, and accelerate the application of millisecond laser in manufacturing and military.
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