纳秒激光加工微凹坑对YG3表面浸润性的影响

研究硬质合金刀具表面浸润性对提高刀具寿命和工件加工表面质量有重要的意义。采用波长1064 nm纳秒脉冲激光在硬质合金YG3表面加工微凹坑阵列,运用光学显微镜、光学轮廓仪和接触角测量仪分别测量微凹坑形貌和表面接触角,研究不同激光功率、扫描次数和微凹坑间距对表面形貌和接触角的影响规律。建立微凹坑几何形貌模型,基于Wenzel理论分析微凹坑形貌变化对表面接触角的影响机理。结果表明:随着平均功率和扫描次数的提高,微凹坑的直径和深度均增大;随着间距的减小,微凹坑分布密度增大。3种条件下表面粗糙度率均增大,表面接触角余弦值随粗糙度率的变化趋势基本一致且成正相关,所以接触角随粗糙度率增加而降低。通过实际接触角与推导接触角的曲线拟合得到了接触角方程。

Effects of Nanosecond Laser-induced Micro-pits on Surface Wettability of YG3

It is of great significance to study the surface wettability of cemented carbide tools for the improvement of tool life and processing surface quality. Micro-pits arrays on the YG3 surface were fabricated by nanosecond pulsed laser with a wavelength of 1064 nm. The optical microscope, optical profiler and contact angle measurement were used to measure the surface morphology and contact angle. The influence of surface morphology on contact angle under different laser average power, scanning times and micro-pits spacing were investigated. Based on Wenzel''s theory, the geometrical morphology model of micro-pits was established to analyze the influence mechanism of surface morphology on contact angle. Results show that the diameter and depth of micro-pits increase as the laser average power or scanning times increase. The micro-pits distribution density increases with decreasing micro-pits spacing. Under three conditions, all the surface roughness ratios increase. The cosine contact angle is positively related to the roughness ratio and the variation trends are basically consistent. As a result, the contact angle decreases with the increase of roughness ratio. The actual contact angle equation is fitted using the variation curves of actual contact angle versus derivation contact angle.