为探究激光毛化火山口坑点形貌特征的演变过程,搭建了LD泵浦窄脉冲Nd∶YAG激光毛化实验装置。针对3A21铝合金试件,选取激光单脉冲能量、脉冲宽度、脉冲数及离焦量作为待研究的工艺参数,采用单因素法研究近平顶光束作用下毛化坑点形貌的演变规律。研究结果表明:单脉冲能量增大时,坑点形貌由倒梯形向倒三角形转变;随着脉冲宽度变窄,坑点周围形成相互竞争的金属熔渣及陨石坑;随着作用于坑点的脉冲数增多,坑点的形貌及其特征参数趋于稳定;随离焦量增大,坑点边缘的微凸体逐渐减小直至消失。研究结果为3A21铝合金材料表面高质量的激光毛化提供参考。

The LD pumped Nd∶YAG laser texturing equipment exhibiting a short pulse is established to explore the evolution process of the crater pit morphology generated by laser texturing. The effects of the process parameters, including the single pulse energy, pulse width, number of pulses, and defocusing amount, are investigated using the single factor method. Further, the evolution law of the texturing pit morphology on the 3A21 aluminum alloy sample surface is analyzed using an almost flat-top laser beam. The results denote that the pit morphology changes from an inverted trapezoid to an inverted triangle with the increasing single pulse energy. The competing metal slag and meteorite crater are formed around the pit as the pulse width narrows; further, the pit morphology and its characteristic parameters are observed to become stable under the action of sufficient pulses, and the micro-protrusion gradually decreases until it vanishes with an increase in the defocusing amount. These results establish a solid technological foundation for the 3A21 aluminum alloy with high-quality and morphology-controllable laser texturing.