基于超快电子衍射的飞秒激光加工汽车用铝材超快超精细晶格动力学过程

Ultrafast and superfine lattice dynamics in metal Al for automobile processed by femtosecond laser based on ultrafast electron diffraction

为提高超短脉冲激光加工汽车铝制零部件的质量,通过超快电子衍射系统分析飞秒激光轰击下铝多晶薄膜的电子衍射时间分辨谱(小于40 ps):在亚毫埃米尺度及ps分辨率内,观测铝多晶声子系统热传导耦合过程,得到晶格温度、晶格结构参数的演化规律。研究原子运动和晶格结构沿各晶向的精细变化,并推断铝薄膜内部晶格结构改变为热致和非热致效应共同作用的结果。研究铝薄膜被飞秒激光加热后内部超快热传递和晶格改变过程,在原子尺度下精细描绘铝晶格动力学图像,可为飞秒激光加工汽车用铝材料技术提供理论依据和数据支持。

In order to improve the processed quality of aluminum automotive components by the ultrashort pulse laser,the electron diffraction time resolution spectrum(less than 40 ps)of aluminum film lattice after femtosecond laser bombardment is studied by ultrafast electron diffraction:the thermal coupling process of phonon system of aluminum polycrystalline is observed in the sub-?ngstrom scale and ps time resolution.The evolutions of lattice temperature and lattice structure parameters are obtained.The subtle variations of atomic motions and lattice structure along the various crystal directions are investigated and attributed to both thermal effect and non-thermal effect.Understanding of energy conduction and lattice changing,as well as an exact description of the ultrafast lattice dynamics of aluminum at the atomic scale provide a more refined theoretical basis and data support for the laser machining of aluminum materials in automotive systems.