飞秒脉冲激光诱导TC4微结构表面抑冰特性实验

飞机发动机进气道前缘唇口积冰将会严重威胁航空安全，仿生研究表明具有微纳结构的疏水表面可以起到良好的抑冰效果。针对飞机唇口材料TC4，采用飞秒脉冲激光诱导制备TC4微结构表面，利用三维形貌仪和扫描电镜对TC4合金表面三维形貌和微纳结构进行观测，应用接触角测量仪分析表面浸润改性，依托结冰特性实验系统测试微结构表面抑冰抑霜性能，并分析飞秒脉冲激光加工工艺参数对表面微观结构和抑霜特性的影响机制。研究结果表明：随着激光扫描速度的增大，TC4合金表面形成的拱形沟壑深度增加，沟壑上方出现干涉条纹以及圆形凸起且微纳凸起的尺寸随扫描速度的增大而增大，接触角先减小后增大再减小；加工后表面液滴冻结时间比未加工表面延迟30 s；扫描速度2 000 mm/s时的液滴冻结时间最长，霜层质量最小，高度最低。飞秒激光加工TC4合金表面形成的微纳结构以及表面吸附的有机物能够改变表面接触角；粗糙度和表面形貌能够影响表面结冰时间和结霜量。

Experiment on ice suppression characteristics of TC4 microstructure surface induced by femtosecond pulse laser

Ice accumulation on the front edge lip of the aircraft engine intake will seriously threaten aviation safety. Bionic research shows that a hydrophobic surface with a micro-nano structure has a desirable ice suppression effect. With the aircraft lip material TC4, a TC4 microstructure surface is prepared using femtosecond pulse laser induction. A three-dimensional topography and a scanning electron microscope are used to observe the three-dimensional topography and micro-nano structure of the TC4 alloy surface. Relying on the icing characteristics experimental system to test the ice and frost resistance performance of the microstructure surface, we analyze the influence mechanism of the femtosecond pulse laser processing technology parameters on the surface microstructure and frost suppression properties. The results show that with the increase of the laser scanning speed, the depth of the arched groove formed on the surface of the TC4 alloy increases, interference fringes and circular protrusions appear above the groove, and the size of the micro-nano protrusion increases with the increase of the scanning speed. The contact angle decreases first and then increases and finally decreases; after processing, the surface droplet freezing time is delayed by 30 s compared to the unprocessed surface; at the scanning speed of 2 000 mm/s, the droplet freezing time is the longest, the frost layer quality the smallest, and the height the lowest. The micro-nano structure formed on the surface of TC4 alloy by femtosecond laser processing and the organic matter adsorbed on the surface can change the surface contact angle, and the roughness and surface morphology can affect the surface freezing time and frost amount.