Gerhard Liedl
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View article: Femtosecond Laser Generation of LaCoO <sub>3</sub> Perovskite Nanocatalysts for Preferential CO Oxidation
Femtosecond Laser Generation of LaCoO <sub>3</sub> Perovskite Nanocatalysts for Preferential CO Oxidation Open
Green synthesis and defect engineering of LaCoO3 model nanocatalysts by femtosecond pulsed laser ablation in liquid (fs-PLAL) led to the formation of two types of nanoperovskites: stoichiometric LaCoO3 and nonstoichiometric cobalt-rich nan…
View article: Chemical and UV Durability of Hydrophobic and Icephobic Surface Layers on Femtosecond Laser Structured Stainless Steel
Chemical and UV Durability of Hydrophobic and Icephobic Surface Layers on Femtosecond Laser Structured Stainless Steel Open
Femtosecond laser processing significantly alters the surface structure and chemical composition, impacting its wetting properties. Post-treatments such as immersion in a hydrocarbon liquid (petrol) or storage in a vacuum can significantly…
View article: Defect-Rich CuZn Nanoparticles for Model Catalysis Produced by Femtosecond Laser Ablation
Defect-Rich CuZn Nanoparticles for Model Catalysis Produced by Femtosecond Laser Ablation Open
Femtosecond laser ablation of Cu0.70Zn0.30 targets in ethanol led to the formation of periodic surface nanostructures and crystalline CuZn alloy nanoparticles with defects, low-coordinated surface sites, and, controlled by the applied lase…
View article: Icing Wind Tunnel and Erosion Field Tests of Superhydrophobic Surfaces Caused by Femtosecond Laser Processing
Icing Wind Tunnel and Erosion Field Tests of Superhydrophobic Surfaces Caused by Femtosecond Laser Processing Open
Ice accumulation on lift-generating surfaces, such as rotor blades or wings, degrades aerodynamic performance and increases various risks. Active measures to counteract surface icing are energy-consuming and should be replaced by passive a…
View article: A compressible multiphase Mass-of-Fluid model for the simulation of laser-based manufacturing processes
A compressible multiphase Mass-of-Fluid model for the simulation of laser-based manufacturing processes Open
A new model for compressible multiphase flows involving sharp interfaces and phase change is presented, that uses a variant of the Volume-of-Fluid model to track phases by advecting their respective mass, and is hence called Mass-of-Fluid …
View article: Formation of Periodic Surface Structures by Multipulse Femtosecond Laser Processing of Au-Coated Ni in Various Fluids
Formation of Periodic Surface Structures by Multipulse Femtosecond Laser Processing of Au-Coated Ni in Various Fluids Open
Using multipulse linearly polarized femtosecond laser processing of a Au-coated Ni surface in various liquid media created subwavelength self-organized nanoripples. The thin gold film improved the laser absorptivity, decreasing the ripple …
View article: Insights into the Correlation between Residual Stresses, Phase Transformation, and Wettability of Femtosecond Laser-Irradiated Ductile Iron
Insights into the Correlation between Residual Stresses, Phase Transformation, and Wettability of Femtosecond Laser-Irradiated Ductile Iron Open
Despite numerous studies on the wettability behavior of ductile iron after ultrafast laser structuring, the correlation between the phase change due to the interaction with an intense pulse and wettability is not yet well understood. In th…
View article: Fast transition from hydrophilic to superhydrophobic, icephobic properties of stainless steel samples after femtosecond laser processing and exposure to hydrocarbons
Fast transition from hydrophilic to superhydrophobic, icephobic properties of stainless steel samples after femtosecond laser processing and exposure to hydrocarbons Open
Femtosecond laser processing is a key technology for surface modification and can be used to trigger superhydrophobic behavior through a combination of topographical and chemical effects. Nevertheless, immediately after laser processing, s…
View article: Near-Infrared Femtosecond Laser Ablation of Au-Coated Ni: Effect of Organic Fluids and Water on Crater Morphology, Ablation Efficiency and Hydrodynamic Properties of NiAu Nanoparticles
Near-Infrared Femtosecond Laser Ablation of Au-Coated Ni: Effect of Organic Fluids and Water on Crater Morphology, Ablation Efficiency and Hydrodynamic Properties of NiAu Nanoparticles Open
Scanning electron microscopy (SEM) and profilometry of the crater morphology and ablation efficiency upon femtosecond laser ablation of Au-coated Ni targets in various fluids revealed a pronounced dependence on the ablation medium. For eth…
View article: A Numerical Investigation of Laser Beam Welding of Stainless Steel Sheets with a Gap
A Numerical Investigation of Laser Beam Welding of Stainless Steel Sheets with a Gap Open
Keyhole laser beam welding (LBW) of 304L stainless steel sheets with a gap in between was numerically simulated with a three-dimensional, transient, multi-physical model for laser material processing based on the finite volume method (FVM)…
View article: Numerical Investigation of Laser Beam Welding of Stainless Steel Sheets with a Gap
Numerical Investigation of Laser Beam Welding of Stainless Steel Sheets with a Gap Open
Keyhole laser beam welding (LBW) of stainless steel sheets with a gap in between is numerically simulated with a three-dimensional, transient multi-physical model for laser material processing. At first, the model’s ability to reprod…
View article: Modelling of temperature fields in DP1000 steel during laser treatment using diffractive optical elements
Modelling of temperature fields in DP1000 steel during laser treatment using diffractive optical elements Open
Diffractive optical elements (DOEs) with their unique properties allow to form a predetermined beam intensity profile in the focal plane. The use of DOEs in laser material processing technologies reveals new possibilities for controlling t…
View article: Experimental study of spatial frequency transition of laser induced periodic surface structures
Experimental study of spatial frequency transition of laser induced periodic surface structures Open
This study shows the influence of laser fluence and pulse number on the spatial frequency distribution of laser induced periodic surface structures (LIPSS) on a stainless steel surface. Also the transition of LIPSS to larger self organized…
View article: Improving Tribological Properties of Stainless Steel Surfaces by Femtosecond Laser Irradiation
Improving Tribological Properties of Stainless Steel Surfaces by Femtosecond Laser Irradiation Open
A possibility of improving tribological properties by femtosecond laser irradiation on an example of a steel surface by creating regularly arranged micro-grooved textures that contain self-organized microstructures and nano laser-induced p…
View article: The influence of the fluid nature on femtosecond laser ablation properties of a SiO<sub>2</sub>/Si target and synthesis of ultrafine-grained Si nanoparticles
The influence of the fluid nature on femtosecond laser ablation properties of a SiO<sub>2</sub>/Si target and synthesis of ultrafine-grained Si nanoparticles Open
Femtosecond laser assisted formation of ultrafine-grained Si NPs with a high density of defects. This can correlate with significant thermal stresses on primary NPs, fast cooling of ejected liquid droplets and incomplete ripening processes.
View article: Conditions improving of laser heating for forming of materials with a ferritic-martensitic structure
Conditions improving of laser heating for forming of materials with a ferritic-martensitic structure Open
High-strength dual phase ferritic-martensitic steels with a controlled amount of martensite have the most favorable combination of durability and plasticity compared to other low-alloy steels. The possibility of conditions improving of las…
View article: Testing of diffractive optical element as part of specific CO<sub>2</sub> laser equipment for metallic materials modification
Testing of diffractive optical element as part of specific CO<sub>2</sub> laser equipment for metallic materials modification Open
Testing of a reflective diffractive optical element (DOE) as part of specific CO 2 laser equipment Oerlikon OPL 2000 for metallic materials modification was performed. The power density distribution in a plane located behind the DOE focal …
View article: Colorization of copper surfaces by nanostructure modifications with ultrashort laser pulses
Colorization of copper surfaces by nanostructure modifications with ultrashort laser pulses Open
A colorization of copper surfaces after nanostructure modifications with ultrashort laser pulses was studied. Femtosecond laser has been used for experiments. A relative motion of the laser beam on the material was realized. Tracks on the …
View article: Study of the action of a femtosecond laser beam on samples of a Cu-Zn alloy
Study of the action of a femtosecond laser beam on samples of a Cu-Zn alloy Open
We performed experimental researches of the action of a femtosecond laser beam on samples of a Cu-Zn alloy with 50 μm thick. We observed at the time of the laser action, the change in the maximum deflection of the cantilevered samples, whi…
View article: Polarisation Measurement of the Emitted Thermal Radiation During Laser Material Processing
Polarisation Measurement of the Emitted Thermal Radiation During Laser Material Processing Open
We present a new approach for quality control in laser material processing.By means of an active optical element (SCPEM -Single Crystal PhotoElastic Modulator) the emitted thermal radiation from the interaction zone of the focused laser ra…
View article: Laser welding of dissimilar metallic materials with use of diffractive optical elements
Laser welding of dissimilar metallic materials with use of diffractive optical elements Open
A use of laser technology it is progressive in the welding of dissimilar materials. Pulsed laser welding of an aluminum alloy AK4 and a titanium alloy VT5-1 was performed. Processing conditions were determined, the realization of which dur…
View article: Features of changes in the nanostructure and colorizing of copper during scanning with a femtosecond laser beam
Features of changes in the nanostructure and colorizing of copper during scanning with a femtosecond laser beam Open
We have studied the nanostructuring and colorizing of the copper surface by scanning with a femtosecond laser beam with a near-Gaussian beam profile. The experimental studies were conducted using a femtosecond laser comprising a Ti:Sapphir…
View article: Laser beam shaping for modification of materials with ferritic-martensitic structure
Laser beam shaping for modification of materials with ferritic-martensitic structure Open
A identify conditions of laser heating for warm forming of materials with a ferritic-martensitic structure was performed. The laser source was a fiber laser with maximum output power of 1500 W. The beam was transformed to an elliptical rin…
View article: Algorithm for calculation of the power density distribution of the laser beam to create a desired thermal effect on technological objects
Algorithm for calculation of the power density distribution of the laser beam to create a desired thermal effect on technological objects Open
Based on the use of methods for solving the inverse problem of heat conduction, we developed an algorithm for calculating the power density distribution of the laser beam to create a desired thermal effect on technological objects. It was …