耦合系数对激光辐照金属材料温度场的影响

摘要

为研究耦合系数随温度变化对短脉冲激光辐照金属材料产生的温度场分布的影响,基于双温耦合理论,建立了短脉冲激光辐照金属材料金加热过程的有限元求解模型.在同时考虑脉冲激光的空间、时间分布和多参数同时随温度变化的情况下,计算得到了短脉冲激光辐照金属材料金激励产生的温度场瞬态分布,比较了耦合系数随温度变化和不随温度变化两种情况下温度场的区别,并进一步得到了两种情况下激光辐照金属材料金后辐照区域附近晶格的轴向分布和径向分布.数值结果表明:随温度变化的耦合系数不仅影响电子和晶格温度的上升快慢和最大值,而且影响着温度场的空间分布.该研究为飞秒激光辐照金属激励产生应力场、超声波声场等的进一步研究提供了理论基础.%Based on the two-temperature theory, a numerical model to solve the heating process at surface vicinity irradiated by ultrashort pulse laser is established to investigate the influence of temperature-dependent coupling of material on temperature field in metal Au irradiated by ultrashort pulse laser.Taking account of the temperature-dependent properties of material and the spatial and temporal shape of the laser pulse, the transient temperature fields by ultrashort pulse laser in metal(Au) is numerical simulated by the finite element method(FEM).The difference of temperature fields from considering and neglecting the temperature-dependent coupling of material is compared ,and the lattice temperature distribution in the vicinity of laser-irradiated region at different depths and at different radial distances are obtained.The numerical results indicate that the temperature-dependent coupling affects not only the electron and lattice temperature rising speed and temperature maximum but also the spatial distribution of temperature field.This study establishes a theory basis for stress field and ultrasound field in metal generated by femtosecond laser.