The favorable combination of high material removal rate and low influence on the material beneath the ultra-short pulsed laser-processed surface are of particular advantage for sample preparation. This is especially true at the micrometer scale or for the pre-preparation for a subsequent focused ion beam milling process. Specific surface features, the laser-induced periodic surface structures, are generated on femtosecond laser-irradiated surfaces in most cases, which pose an issue for surface-sensitive mechanical testing or microstructural investigations. This work strives for an approach to enhance the surface quality of glancing-incident laser-processed surfaces on the model material copper with two distinctly different grain sizes. A new generalized perspective is presented, in which optimized parameter selection serves to counteract the formation of the laser-induced periodic surface structures, enabling, for example, grain orientation mapping directly on femtosecond laser processed surfaces.

Direct laser writing by two‐photon lithography enables the manufacturing of tailored 3D objects, commonly referred to as 3D‐printing, with submicrometer precision. Thereby, new approaches are enabled for miniaturized optical and mechanical devices, where basic material properties act as design guideline and initial input for finite element simulation‐driven device design. These mechanical properties are accessible through micromechanical testing and suitably adapted miniaturized specimens. With direct laser writing, a micromechanical specimen geometry can be readily manufactured without additional postprocessing, enabling the possibility of repetitive sample production and further high‐throughput testing. Widely overhanging features, as in common bending beam or tension specimens, easily cause floating layers as writing artifacts and thereby undefined geometries. Within this work, an approach to overcome this issue is presented. By introducing a slight taper within the geometry at initially printed layers, a reliable sample geometry is achievable without changing the overall mechanical behavior. As showcase geometries, miniaturized notched cantilever and advanced push‐to‐pull devices incorporating a notched tension specimen are detailed. Mechanical testing is conducted in situ and ex situ, and the mechanical influence from introducing a taper to a straight geometry is assessed via a finite element modeling. Thereby, a comprehensive approach for high‐throughput micromechanical testing is established.

Correlation of characteristic surface appearance and surface roughness with measured air kerma (kinetic energy released in air) reduction of tungsten-rhenium (WRe) stationary anode surfaces. Methods: A stationary anode test system was developed and used to alter nine initially ground sample surfaces through thermal cycling at high temperatures. A geometrical model based on high resolution surface data was implemented to correlate the measured reduction of the air kerma rate with the changing surface appearance of the samples. In addition to the nine thermally cycled samples, three samples received synthetic surface structuring to prove the applicability of the model to nonconventional surface alterations. Representative surface data and surface roughness values were acquired by laser scanning confocal microscopy. Results: After thermal cycling in the stationary anode test system, the samples showed surface features comparable to rotating anodes after long-time operation. The established model enables the appearance of characteristic surface features like crack networks, pitting, and local melting to be linked to the local x-ray output at 100 kV tube voltage ,10°anode take off angle and 2 mm of added Al filtration. The results from the conducted air kerma measurements were compared to the predicted total x-ray output reduction from the geometrical model and show, on average, less than 10 % error within the 12 tested samples. In certain boundaries, the calculated surface roughness R a showed a linear correlation with the measured air kerma reduction when samples were having comparable damaging characteristics and similar operation parameters. The orientation of the surface features had a strong impact on the measured air kerma rate which was shown by testing synthetically structured surfaces.Conclusions: The geometrical model used herein considers and describes the effect of individual surface features on the x-ray output. In close boundaries arithmetic surface roughness R a was found to be a useful characteristic value on estimating the effect of surface damage on total x-ray output.

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