Inhaltszusammenfassung

Conventional tactile methods determine the surface hardness of materials such as ceramics or metals mechanically by comparing abrasions or indentations on the material surface. This mechanical process is time-consuming and the surface of the sample is severely affected by small craters. With these classic hardness testing methods (Brinell, Rockwell, Moog, Vickers) it is almost impossible to map an inhomogeneous distribution of the material hardness. However, in industry the visualization of d...Conventional tactile methods determine the surface hardness of materials such as ceramics or metals mechanically by comparing abrasions or indentations on the material surface. This mechanical process is time-consuming and the surface of the sample is severely affected by small craters. With these classic hardness testing methods (Brinell, Rockwell, Moog, Vickers) it is almost impossible to map an inhomogeneous distribution of the material hardness. However, in industry the visualization of differently hardened areas of components would be of great interest. During the hardening process, the structure of the unit cell near the sample surface changes and thereby determines the hardness of the sample. LIBS spectra can give an indication of the surface hardness. Using LIBS mapping in combination with suitable evaluation methods, we were able to spatially resolve the tendency of the hardness distribution on selected low-alloy carbon steel samples with differently hardened areas. To estimate the local surface hardness, we calculated the ratio of the ionic to the atomic spectral line intensities (Fe II / Fe I) under constant conditions. In order to exclude the influence of other material parameters, such as the chemical composition, we heat-treated and tempered pieces of the sample material (80CrV2, material number 1.2235), which resulted in different distributions of the material hardness on the sample surface. Combining the measurement procedure of the spectral analysis with a mapping process, spatially resolved images of the surface hardness can be obtained. We compare our measurements at different laser fluences with conventional methods for determining material hardness.» weiterlesen» einklappen

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Klassifikation

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

DDC Sachgruppe:
Physik