摘要
基于双曲双温两步热传导和热电子崩力模型,考虑到超快脉冲激光辐照金属薄膜材料过程中的热-力耦合效应,得到了完全耦合的、非线性的超快热弹性模型.运用具有人工粘性和自适应步长的有限差分算法,以脉宽为100fs的脉冲激光辐照200nm厚金膜为例,对薄膜体内的电子-晶格温度及温度梯度、热应力和电子热流进行了数值模拟研究.结果表明:脉冲辐照早期为明显的非平衡加热阶段,同时形成较大的热电子崩力;电子热流出现双峰现象;超快加热引起的热应力是导致薄膜力学损伤的主要原因.
Based on the dual-temperature hyperbolic two-step heat conduction and hot- electron blast models, a new set of fully coupled and nonlinear ultra-fast thermo-elasticity model was derived to investigate the thermo-mechanical coupling effect of metal films caused by ultra-fast pulsed laser. Taking the 200nm gold film irradiated by a 100fs laser pulse as a typical example, thermal stress development in the lattice sub-system, temperature along with temperature gradient and electron heat flux were modeled by using artificial viscosity and the adaptive step finite-difference algorithm. It is shown that the early period of laser heating is a non-equilibrium process and forming large hot-electron blast force. It is also found that electron heat flow presents bimodal phenomenon. In addition, thermal stress induced by ultra-fast laser heating could be the main reason for mechanical damage.
出处
《光子学报》
EI
CAS
CSCD
北大核心
2008年第11期2172-2176,共5页
Acta Photonica Sinica
关键词
超快脉冲激光
金属薄膜
超快热弹
热应力
非热平衡
Ultra-fast pulse Laser
Metal films
Ultra-fast thermo-elasticity
Thermal stress
Non-thermal equilibrium
