Reich Stefan, Göbel Alexander, Goesmann Marcel, Heunoske Dominic, Schäffer Sebastian, Lueck Martin, Wickert Matthias, Osterholz Jens
Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMI, Ernst-Zermelo Straße 4, 79104 Freiburg, Germany.
Materials (Basel). 2022 May 24;15(11):3743. doi: 10.3390/ma15113743.
During laser penetration, the irradiated samples form a melt pool before perforation. Knowledge of the dynamics of this melt pool is of interest for the correct physical description of the process and leads to improved simulations. However, a direct investigation, especially at the location of high-power laser interaction with large spot diameters in the centimeter range is missing until now. Here, the applicability of 2D triangulation for surface topology observations is demonstrated. With the designed bidirectional 2D triangulation setup, the material cross-section is measured by profile detection at the front and back side. This allows a comprehensive description of the penetration process to be established, which is important for a detailed explanation of the process. Specific steps such as surface melting, indentations, protrusions during melt pool development and their dynamics, and the perforation are visualized, which were unknown until now. Furthermore, a scanning 3D triangulation setup is developed to obtain more information about the entire melt pool at the front side, and not just a single intersection line. The measurements exhibit a mirror-symmetric melt pool and the possibility to extrapolate from the central profile to the outer regions in most cases.
在激光穿透过程中，被辐照的样品在穿孔前会形成一个熔池。了解这个熔池的动力学对于正确地从物理角度描述该过程很有意义，并且有助于改进模拟。然而，到目前为止，尚未有直接的研究，尤其是在高功率激光与厘米级大光斑直径相互作用的位置。在此，展示了二维三角测量法在表面拓扑观测中的适用性。利用设计的双向二维三角测量装置，通过对正面和背面的轮廓检测来测量材料的横截面。这使得能够建立对穿透过程的全面描述，这对于详细解释该过程很重要。诸如表面熔化、熔池形成过程中的凹痕、凸起及其动力学以及穿孔等具体步骤都得以可视化，而这些在此之前是未知的。此外，还开发了一种扫描三维三角测量装置，以获取关于正面整个熔池的更多信息，而不仅仅是一条单一的交线。测量结果显示出一个镜像对称的熔池，并且在大多数情况下有可能从中心轮廓推断出外部区域的情况。
