TA15钛合金氧化膜激光清洗温度场有限元模拟

Finite element simulation of temperature field in laser cleaning of TA15 titanium alloy oxide film

激光清洗是一种利用短脉冲高功率密度激光辐照清洗对象,通过激光和清洗对象发生复杂的物理化学作用,实现污染物被去除的非接触式清洗方式.激光清洗机制十分复杂,主要包括光致分解、光致剥离和光致振动,均与激光清洗过程的温度场分布规律密切相关.本文采用Comsol Multiphysics商业模拟软件,建立了TA15钛合金氧化膜激光清洗有限元仿真模型,分析了光斑形状、激光能量与加载方式、脉冲宽度等对钛合金氧化膜激光清洗过程温度场变化的影响规律.结果表明,在毫秒脉冲激光作用下基材损伤严重,脉冲宽度越短表面热扩散越小,方形平顶光斑较高斯光斑加热更均匀,矩形脉冲较高斯光斑维持高温时间短,基材不易损伤.当方形平顶微秒脉冲激光以矩形加载方式时,钛合金氧化膜激光清洗效果最佳.

Laser cleaning is a noncontact cleaning method that uses a short-pulse high power density laser to irradiate an object.The pollutants are removed by the complex physical and chemical interactions between the laser and the object to be cleaned.The mechanism of laser cleaning is very complex,including photodegradation,photodetachment,and photovibration,which are closely related to the temperature distribution in the laser-cleaning process.In this study,the finite element simulation model of laser cleaning of TA15 titanium alloy oxide film is established by using Comsol Multiphysics commercial simulation software.The influence of spot shape,laser energy,loading mode,and pulse width on the titanium alloy oxide film temperature field is analyzed.The results showed that the substrate was severely damaged by a millisecond pulse laser.The shorter the pulse width,the smaller the surface thermal diffusion.The square flat-top spot was more evenly heated than the Gaussian spot,and the rectangular pulse was less damaged than the Gaussian spot.The laser-cleaning effect of titanium alloy oxide film was the best when the square flat-top laser was loaded in a rectangular pulse.