飞秒激光诱导TC4表面微观组织研究

为探究超快激光对金属材料的烧蚀特性,利用飞秒脉冲激光加工TC4,研究加工后TC4表面的形貌特点,分析飞秒激光加工金属的作用机理。当激光能量密度为8.05 J/cm2时,用白光干涉和扫描电镜观察不同扫描速度下材料表面的形貌变化。随着扫描速度的降低,表面条纹变深,条纹上方的二级微纳凸起尺寸增大,粗糙度增加,条纹侧面出现经典低空间频率条纹。从高斯光束特点和光斑重叠率角度对各种形貌的形成机理进行分析,高斯光束光斑中心处能量密度高,条纹上方形成凸起,侧面形成经典条纹；当光斑重叠率越大,单位面积内能量密度就越大,表面微结构尺寸也随之增大。

Study on microstructure of TC4 surface induced by femtosecond laser

In order to explore the ablation characteristics of ultrafast lasers on metal materials,TC4 was processed by femtosecond pulsed laser to study the surface morphology of TC4 after processing,and the mechanism of femtosecond laser processing of metals was analyzed.When the laser energy density was 8.05 J/cm2,the surface morphology of the material at different scanning speeds was observed by white light interference and scanning electron microscopy.As the scanning speed decreases,the surface fringes become deeper,the size of the secondary micro-nano bump above the stripe increases,the roughness increases,and the classic low spatial frequency fringes appear on the side of the stripe.The formation mechanism of various morphologies is analyzed from the characteristics of Gaussian beam and the overlap ratio of the spot.The energy density at the center of the Gaussian beam is high,the bulge is formed above the stripes,and the classic stripes are formed on the sides.When the spot overlap rate is larger,the unit area is within the greater the energy density,the larger the surface microstructure size.