Inhaltszusammenfassung

Conventional methods for assessing hardness such as Brinell, Rockwell, or Vickers tests are based on tactile, i.e. mechanical contact measurements that are constrained by sample geometry and thickness. Due to the large indentations, they cause considerable mechanical damage to the sample surface. This work investigates the potential use of laser-induced breakdown spectroscopy as a fast, semi-quantitative and contactless alternative for visualizing surface hardness distributions with the poten...Conventional methods for assessing hardness such as Brinell, Rockwell, or Vickers tests are based on tactile, i.e. mechanical contact measurements that are constrained by sample geometry and thickness. Due to the large indentations, they cause considerable mechanical damage to the sample surface. This work investigates the potential use of laser-induced breakdown spectroscopy as a fast, semi-quantitative and contactless alternative for visualizing surface hardness distributions with the potential for improved spatial resolution in the future. The correlation between local surface hardness and the ratio of ionic to atomic line intensities has recently been reported1. To produce different degrees of hardness while minimizing the influence of varying chemical compositions, low-alloy steel samples from a single batch are subjected to manual heat treatment. Correlations between ratio of iron ionic to atomic line intensities and mechanical hardness of sample surfaces were found. By scanning the surfaces of the steel samples, detailed spatially resolved maps of the surface hardness distribution can be displayed. However, subsequent nanosecond laser pulses targeted at the same local position on the surface of hardened samples cause local melting, changes in the surface structure and possibly material softening at the sample surface, preventing further scans without additional surface preparation steps.» weiterlesen» einklappen

Autoren

Klassifikation

DFG Fachgebiet:
3.23 - Optik, Quantenoptik und Physik der Atome, Moleküle und Plasmen

DDC Sachgruppe:
Physik