Fundamental investigations of ultrashort pulsed laser ablation on stainless steel and cemented tungsten carbide

Lickschat, Peter; Metzner, Daniel; Weißmantel, Steffen

doi:10.1007/s00170-020-05502-8

Cited by 42 publications

(26 citation statements)

References 29 publications

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“…However, as can be seen in Fig. 12, the calculated values fit well to the determined experimental values from this study for 3 J/cm 2 in the high fluence regime, for 0.75 J/cm 2 in the low fluence regime, and are comparable to [10,64]. Fig.…”

Section: Effective Penetration Depthssupporting

confidence: 84%

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Experimental and Theoretical Determination of the Effective Penetration Depth of Ultrafast Laser Radiation in Stainless Steel

Metzner

Olbrich

Lickschat

et al. 2020

Lasers Manuf. Mater. Process.

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This study intends to present a simple two-temperature model (TTM) for the fast calculation of the ablation depth as well as the corresponding effective penetration depth for stainless steel by considering temperature-dependent material parameters. The model is validated by a comparison of the calculated to the experimentally determined ablation depth and the corresponding effective penetration depth in dependence on the pulse duration (200 fs up to 10 ps) and the fluence. The TTM enables to consider the interaction of pulsed laser radiation with the electron system and the subsequent interaction of the electrons with the phonon system. The theoretical results fit very well to the experimental results and enable the understanding of the dependence of the ablation depth and of the effective penetration depth on the pulse duration. Laser radiation with a pulse duration in the femtosecond regime results in larger ablation depths compared to longer-pulsed laser radiation in the picosecond regime. Analogously to the ablation depth, larger effective penetration depths are observed due to considerably higher electron temperatures for laser radiation with pulse durations in the femtosecond regime.

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Section: Effective Penetration Depthssupporting

confidence: 84%

“…11 Reflectance R as a function of the electron temperature T e for iron at a wavelength λ = 1030 nm and λ = 400 nm based on [25] Fig. 12 Calculated effective penetration depth as a function of the pulse duration in comparison to experimental values from this study (black dots) and [10,64]…”

Section: Effective Penetration Depthsmentioning

confidence: 98%

Experimental and Theoretical Determination of the Effective Penetration Depth of Ultrafast Laser Radiation in Stainless Steel

Metzner

Olbrich

Lickschat

et al. 2020

Lasers Manuf. Mater. Process.

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“…Thereby, the damage threshold at ΔL = 40 and 70 μm was almost equal, whereas the damage threshold was significant lower for ΔL = 20 μm (Figure 5), probably due to the accumulation of small modifications also known as incubation. 41 The measured surface topologies after irradiation below and above the damage threshold are presented in the SI III. An explanation of the changing damage threshold is beyond the scope of this study.…”

Section: ■ Experimental Resultsmentioning

confidence: 99%

Spatial Conductivity Distribution in Thin PEDOT:PSS Films after Laser Microannealing

Pflug

Anand

Busse

et al. 2021

ACS Appl. Electron. Mater.

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In contrast to conventional methods for increasing the conductivity of transparent polymer electrodes based on additives, solvent treatment, or hot plate thermal processing, laser heating enables the selective annealing of defined areas of a material on the micrometer scale. This study investigates the spatial conductivity distribution of thin PEDOT:PSS films after selective heating by continuous wave (cw) laser radiation without damaging the material. The sheet resistances of the samples decreased abruptly above a certain threshold intensity and a changed relative permittivity of the irradiated material was detected by imaging ellipsometry. A theoretical model has been derived to estimate the resulting spatial conductivity distribution induced by the inhomogeneous heating with the Gaussian spatial intensity distribution of the applied laser radiation. In combination with the experimental measurements, the model revealed that the conductivity increased proportionally to the intensity above the threshold intensity, but remained unchanged below, resulting also in a Gaussian spatial conductivity distribution. Thus, in contrast to conventional oven annealing where only large-area averaged annealing is possible, laser annealing allows to tailor the spatial distribution of the conductivity on a micrometer scale opening applications for future micro systems.

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“…Shorter pulse durations decrease the fluence threshold. Lickschat et al [ 87 ], when investigating ultrashort pulse durations, found the ablation threshold of WC decreased from 0.4 J/cm 2 to 0.26 J/cm 2 as the pulse duration decreased from 10 ps to 0.2 ps, respectively. Fang et al [ 88 ] using green laser light (532 nm) also demonstrated a decrease in ablation threshold on WC-CoNi from 2.5 J/cm 2 to 0.5 J/cm 2 when the pulse duration regime was changed from nanosecond to picosecond.…”

Section: Fabrication Of Surface Texturesmentioning

confidence: 99%

Laser Processing of Hard and Ultra-Hard Materials for Micro-Machining and Surface Engineering Applications

2021

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Polycrystalline diamonds, polycrystalline cubic boron nitrides and tungsten carbides are considered difficult to process due to their superior mechanical (hardness, toughness) and wear properties. This paper aims to review the recent progress in the use of lasers to texture hard and ultra-hard materials to a high and reproducible quality. The effect of wavelength, beam type, pulse duration, fluence, and scanning speed is extensively reviewed, and the resulting laser mechanisms, induced damage, surface integrity, and existing challenges discussed. The cutting performance of different textures in real applications is examined, and the key influence of texture size, texture geometry, area ratio, area density, orientation, and solid lubricants is highlighted. Pulsed laser ablation (PLA) is an established method for surface texturing. Defects include melt debris, unwanted allotropic phase transitions, recast layer, porosity, and cracking, leading to non-uniform mechanical properties and surface roughness in fabricated textures. An evaluation of the main laser parameters indicates that shorter pulse durations (ns—fs), fluences greater than the ablation threshold, and optimised multi-pass scanning speeds can deliver sufficient energy to create textures to the required depth and profile with minimal defects. Surface texturing improves the tribological performance of cutting tools in dry conditions, reducing coefficient of friction (COF), cutting forces, wear, machining temperature, and adhesion. It is evident that cutting conditions (feed speed, workpiece material) have a primary role in the performance of textured tools. The identified gaps in laser surface texturing and texture performance are detailed to provide future trends and research directions in the field.

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Fundamental investigations of ultrashort pulsed laser ablation on stainless steel and cemented tungsten carbide

Cited by 42 publications

References 29 publications

Experimental and Theoretical Determination of the Effective Penetration Depth of Ultrafast Laser Radiation in Stainless Steel

Experimental and Theoretical Determination of the Effective Penetration Depth of Ultrafast Laser Radiation in Stainless Steel

Spatial Conductivity Distribution in Thin PEDOT:PSS Films after Laser Microannealing

Laser Processing of Hard and Ultra-Hard Materials for Micro-Machining and Surface Engineering Applications

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