超短激光燒蝕金屬溫度場的求解和分析

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摘要 超快激光與物質(zhì)相互作用的特點，與長脈沖激光截然不同。這使得超快激光加工具有很多獨特的優(yōu)點：高精度、熱效應(yīng)小等。這些優(yōu)點都是由超快激光與物質(zhì)相互作用的機(jī)理決定的。
本文在飛秒激光條件下，對一維雙溫方程進(jìn)行化簡，并用有限差分的方法，對飛秒激光燒蝕金屬銅的溫度場進(jìn)行了數(shù)值模擬。對電子系統(tǒng)和晶格系統(tǒng)的溫度變化進(jìn)行模擬，得到了電子及晶格溫度在一定時間和深度范圍內(nèi)的變化曲線圖，同時得到了單脈沖的燒蝕深度。改變激光的能量密度，研究了電子晶格耦合時間隨能量密度變化的規(guī)律和能量密度對燒蝕深度的影響。模擬結(jié)果證實，激光能量與電子晶格的耦合時間緊密相關(guān)：在燒蝕閾值范圍之內(nèi)，如果增大能量密度的，電子晶格耦合時間也隨之增大；能量密度對燒蝕深度也有影響，在一定范圍內(nèi)，能量密度愈大，燒蝕深度愈深。

關(guān)鍵詞 超短激光加工 雙溫方程 電子晶格耦合時間 差分方程 燒蝕深度




Abstract
The characteristics of interaction between the fast laser and material,is different from long pulse.It makes the ultrafast laser processing has many unique advantages,such as high precision, small heat effect, etc,which are made by the principle of interaction between the fast laser and material.
in this paper, using the one dimension of the double temperature equation, and the finite difference method, the temperature field of ablation copper are simulated.Based on the ablation process, the imbalance of the electronic and lattice temperature, respectively, to the electronic systems and grid systems, to simulate the temperature change of the electronic and lattice temperature changes in a certain time and depth within the scope of the graph,Get the ablation depth of the single pulse at the same time. Was studied by changing the laser energy density, electron lattice coupling law of time changing with the energy density and energy density effects on the ablation depth.Simulation results show that the laser energy is closely related to the electronic lattice coupling time, within the scope of the ablation threshold, with the increase of the energy density, electronic lattice coupling time also increase; Within a certain range, the greater the energy density, the deeper the ablation depth.
Keyword Ultrashort laser processing Double temperature equation Electronic lattice coupling of time Difference equation The ablation depth


目錄

第一章 緒論 4
1.1飛秒激光的發(fā)展史 4
1.2飛秒激光的特點及應(yīng)用 5
1.3 飛秒激光加工和長脈沖加工的特點和比較 5
1.4 飛秒激光參數(shù)對加工的影響 6
1.5 國內(nèi)外超快激光加工的研究現(xiàn)狀 7
第二章 超短激光與金屬材料相互作用的理論基礎(chǔ) 10
2.1 飛秒激光加工機(jī)理的研究進(jìn)展 10
2.2 超快激光與物質(zhì)相互作用的機(jī)理 11
2.3 數(shù)學(xué)模型(雙溫方程) 14
2.3.1 在飛秒激光條件下雙溫模型的簡化 14
2.3.2 飛秒,納秒激光條件下雙溫方程的數(shù)值計算 17
第三章 超短激光燒蝕金屬銅溫度場的計算和分析 19
3.1 思路概述 19
3.2 靶金屬銅的物理參數(shù) 19
3.3 溫度場數(shù)值計算結(jié)果 19
3.4 結(jié)果分析 25
3.4.1 電子晶格熱弛豫時間 25
3.4.2在不同深度處電子晶格的溫度變化 25
3.5 納秒激光燒蝕和飛秒激光燒蝕的比較 27
第四章總結(jié)與展望 28
致謝 29
參考文獻(xiàn) 30