文章信息/Info

Title:

Numerical Simulation of Femtosecond Laser Ablation of Stent Material

作者:

王雷雷; 鄭洋洋; 霍 揚; 劉建英; 李春霞; 盧 洋

山東理工大學機械工程學院

Author(s):

WANG Leilei; ZHENG Yangyang; HUO Yang; LIU Jianying; LI Chunxia;  LU Yang

School of Mechanical Engineering, Shandong University of Technology

關鍵詞:

飛秒激光; 鎳鈦合金; 血管支架; 雙溫方程; 電子溫度; 晶格溫度

Keywords:

femtosecond laser;  nickel titanium alloy;  vascular stent;  two-temperature model;  electron temperature;  lattice temperature

DOI:

10.7502/j.issn.1674-3962.2017.03.10

文獻標志碼:

A

摘要:

為了研究飛秒脈沖激光燒蝕血管支架材料的特性，利用考慮了電子之間熱傳導項的雙溫模型，采用有限差分法，對飛秒激光燒蝕NiTi合金的溫度場分布進行數值模擬，計算得到了電子溫度和晶格溫度隨時間和燒蝕深度的變化規(guī)律，進一步討論了不同激光能量密度、不同激光脈寬、不同延遲時間對電子和晶格的溫度場影響。發(fā)現血管支架材料在飛秒激光的作用下，先是電子吸收能量溫度快速升高，再通過電聲耦合作用將能量傳遞給晶格，最后兩者的溫度達到一個平衡狀態(tài)；激光能量密度主要影響電子的峰值溫度和電子與晶格的平衡溫度；脈沖寬度主要影響電子的峰值溫度和達到峰值溫度所用的時間；電子溫度隨著延遲時間的增加先升高后降低，晶格溫度隨著延遲時間的增加不斷上升。這些理論分析對實際飛秒激光加工血管支架有重要的指導意義。

Abstract:

In order to study the characteristics of femtosecond laser ablation of stent material, two-temperature model which considers the thermal conduction between the electronics, and finite difference method were used to simulate temperature field of NiTi alloys during femtosecond laser ablation. According to the results, the influences of laser energy density, pulse width and delay time on the temperature field of electron and lattice were discussed. The results showed that the temperature of electron and lattice finally reached a state of equilibrium. Before that, firstly, the temperature of electron increased rapidly due to energy absorption, then, the absorbed energy was transferred to lattice through electron phonon coupling effect; at last, the equilibrium would be reached. Laser energy density played a major role in the equilibrium temperature, and pulse width determined the peak temperature and the time to reach it. Consequently，the temperature of electrons first increased and then decreased with the increase of the delay time, but lattice temperature only increased with the increase of the delay time. The results may have an important guiding significance to actual processing of femtosecond laser ablation of vascular stent.