为了研究同轴激光熔覆过程中球形粉末粒子和激光的相互作用, 为激光熔覆中激光器和粒子的选择提供一定的理论依据, 在进行了一定假设的前提下, 应用米氏(Mie)散射理论建立了激光被球形粉末粒子散射的物理模型, 应用Mathematica数学软件绘制出了在不同粒子半径和不同激光波长情况下, 激光被球形粉末粒子散射后的强度分布图, 并对模拟结果进行了分析。研究结果显示：金属粉末粒子的半径和激光的波长是影响激光散射强度分布的重要因素。结果表明：当光学常数q≤30的时候, 散射光强在偏离传播方向20°以外还有一个次极大值, 且次极大值占总散射光强比例较大, 不利于熔池的形成; 当光学常数q≥30的时候, 散射后的光强主要集中在偏离传播方向5°～6°的小范围内, 且在此范围内的散射强度很高, 有利于提高激光熔覆效率。

In order to analyze the interaction of laser and spherical particles in coaxial laser cladding, the physical model of laser scattering by spherical particles is established by using Mie scattering theory in certain assumptions, which will help select the laser and the spherical powder.The distributions of laser intensity with radius of particles and wavelength of laser were drawn by Mathematica software. The simulated results were analyzed. The results show the particles radius and laser wavelength are important parameters affecting the distribution of scattering intensity. There is a secondary maximum with direction deviation beyond 20° as the optical factor is less than 30. It accounts for a higher proportion of scattered light intensity, and it is adverse to the formation of molten pool. The scattering intensity is concentrated in the range from 5° to 6° as the optical factor is more than 30, and the scattering intensity is very strong in this range, which will promote laser cladding.