Nd:YAG连续激光烧蚀碳纤维复合材料的过程观测

通过Nd:YAG激光辐照碳纤维/环氧树脂复合材料过程的高速摄像观测,得到了不同辐照功率密度下烧蚀过程中的主要现象.发现在低功率密度(50 W/cm2)下,主要是表面烧蚀机制,不会发生燃烧现象,在长时间辐照下,由于表层附近出现轻微的聚合物焦化分解,表面层出现粉末状和漂絮状的碳粉缓缓弥散空气中;在中等功率密度(300 W/cm2)下,体烧蚀机制占主要地位,内层分解气体喷出,在空气中点燃引起表面燃烧,主要燃烧表面聚合物;在高功率密度(4500 W/cm2)下是以表面烧蚀为主的质量迁移机制,在极短的时间(0.001 s)内表面层被破坏,瞬间燃烧,光斑中心出现喷射式的气化等离子体现象,并出现逐层烧蚀和各向异性热传导引起的烧蚀区形貌变形等现象.

Observation on the Process of Continuous-Wave Nd:YAG Laser Ablation on Carbon Fiber Composite Material

The phenomena in ablation process of Nd:YAG laser irradiating carbon fibers reinforced epoxy resins composites under different intensities were observed by high-speed camera. Below low intensity (50 W/cm2), composite material laser ablation is dominated by surface ablation mechanism rather than burning, and the surface slight decomposing leads to form carbon powder or flocs which slowly disperse into the air under long time irradiation; At middle intensity of 300 W/cm2 composite material laser ablation is dominated by volume ablation mechanism, inner decomposition gases spill into the air and ignite surface combustion; At high intensity 4500 W/cm2 the main mechanism of the mass ablation is surface ablation, surface layer is damaged and instantaneously burns in a very short time (0.001 s), jet of plasma forms in the center of laser spot, anisotropic heat conduction causes layered ablation and deforms the ablation zone appearance.