Inhaltszusammenfassung

We investigated the potential of femtosecond laser-induced breakdown spectroscopy (fs-LIBS) for rapid and minimally invasive assessment of surface hardness in thermally treated steel samples. Conventional tactile hardness testing methods such as Brinell, Vickers, and Rockwell require extensive sample preparation and specific geometric conditions, making them less suitable for fast or in situ evaluations. Laser-induced breakdown spectroscopy (LIBS) provides a contactless method of material ...We investigated the potential of femtosecond laser-induced breakdown spectroscopy (fs-LIBS) for rapid and minimally invasive assessment of surface hardness in thermally treated steel samples. Conventional tactile hardness testing methods such as Brinell, Vickers, and Rockwell require extensive sample preparation and specific geometric conditions, making them less suitable for fast or in situ evaluations. Laser-induced breakdown spectroscopy (LIBS) provides a contactless method of material analysis with minimal surface damage and high spatial resolution. In previous work [1], we showed that nanosecond LIBS (ns-LIBS) leads to the formation of melt products and slag deposits around the ablation craters, which complicates subsequent surface hardness measurements and thus limits the spatial resolution. To overcome these limitations, we employed femtosecond laser pulses to generate reproducible plasmas on steel samples of varying hardness. By keeping LIBS-determining parameters such as laser pulse energy, surface roughness, and laser spot size constant, we analyzed the spectral variations in relation to the mechanical properties using an integrating spectrometer. Our results reveal a correlation between the intensity ratios of iron emission lines and material hardness, highlighting the sensitivity of fs-LIBS to microstructural changes. Compared to ns-LIBS, fs-LIBS produces significantly smaller ablation craters, reducing surface alteration. Consequently, fs-LIBS represents a promising alternative for the rapid, minimally invasive hardness characterization of finely structured or heat-sensitive components. [1] L. Retterath, P. Kohns, G. Ankerhold, Surface hardness imaging of a low-alloy steel using laser-induced breakdown spectroscopy, Spectrochim. Acta B At. Spectrosc., 219 (2024) 107003. https://doi.org/10.1016/j.sab.2024.107003 » weiterlesen» einklappen

Autoren

Klassifikation

DFG Fachgebiet:
3.21-01 - Experimentelle Physik der kondensierten Materie

DDC Sachgruppe:
Physik