超快激光切割金属材料中快速相变的数值模拟

采用二维双温度模型对多脉冲激光照射金薄板的相变传热情况进行研究,通过等效比热容方法确定固液界面的位置并研究了激光参数对传热过程的影响。结果表明,当激光垂直照射金薄板时,表面整体温度不断上升,而在脉冲间隔时间内略有下降,但温度的峰值相比激光作用的中心有延迟。随着激光的移动,激光照射点处的温度会出现一个峰值,之后会回落。激光作用时间内热影响区的横向变化比纵向大,移动光源向内部的热传递占主要作用,脉冲间隔时间内,热影响区的纵向变化比横向大,金薄板内部导热占主要作用。随着激光的照射,熔化状态横向不断增加的同时,熔化的深度也在不断增加。提高入射脉冲激光能量,会导致熔化的时间提前且熔化深度增加。

Numerical simulation on the rapid phase transformation of metal under the action of moving light source

The phase change heat transfer of multi-pulse laser irradiated gold thin plates was studied by using a two-dimensional dual temperature model. The position of solid-liquid interface was determined by the equivalent specific heat capacity method and the influence of laser parameters on the heat transfer process was studied. The results show that when the laser illuminates the gold thin plate vertically, the overall temperature of the surface increases continuously, but decreases slightly during the pulse interval, and the temperature peak is slightly delayed compared to that at the center of the laser action. As the laser moves, the temperature at the laser spot will show a peak and then fall back. The lateral change of the heat-affected zone during laser action is larger than the longitudinal one, where the heat transfer from the moving light source to the inside plays a major role. During the pulse interval, the longitudinal change of the heat-affected zone is larger than the lateral one, where the internal heat conduction of the gold thin plate plays a major role. As the laser is irradiating, the melting state extends continuously in the lateral direction, while the depth of melting is also constantly increasing. Increasing the incident pulse laser energy causes the melting time to advance and the melting depth to increase.