Thermal simulation of pulsed direct laser interference patterning of metallic substrates using the smoothed particle hydrodynamics approach

Demuth, Cornelius; Bieda, Matthias; Lasagni, Andrés Fabían; Mahrle, Achim; Wetzig, Andreas; Beyer, Eckhard

doi:10.1016/j.jmatprotec.2011.10.023

Cited by 19 publications

(23 citation statements)

References 21 publications

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“…On the contrary, SPH was rarely employed to address the effects of nanosecond laser pulses. The authors of this manuscript previously suggested a thermal model of DLIP for metallic substrates [35]. Cao and Shin predicted the particle motion due to phase explosion during high fluence laser ablation of metals by SPH [36].…”

Section: Introductionmentioning

confidence: 99%

An Incompressible Smoothed Particle Hydrodynamics (ISPH) Model of Direct Laser Interference Patterning

Demuth

Lasagni

2020

Computation

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Functional surfaces characterised by periodic microstructures are sought in numerous technological applications. Direct laser interference patterning (DLIP) is a technique that allows the fabrication of microscopic periodic features on different materials, e.g., metals. The mechanisms effective during nanosecond pulsed DLIP of metal surfaces are not yet fully understood. In the present investigation, the heat transfer and fluid flow occurring in the metal substrate during the DLIP process are simulated using a smoothed particle hydrodynamics (SPH) methodology. The melt pool convection, driven by surface tension gradients constituting shear stresses according to the Marangoni boundary condition, is solved by an incompressible SPH (ISPH) method. The DLIP simulations reveal a distinct behaviour of the considered substrate materials stainless steel and high-purity aluminium. In particular, the aluminium substrate exhibits a considerably deeper melt pool and remarkable velocity magnitudes of the thermocapillary flow during the patterning process. On the other hand, convection is less pronounced in the processing of stainless steel, whereas the surface temperature is consistently higher. Marangoni convection is therefore a conceivable effective mechanism in the structuring of aluminium at moderate fluences. The different character of the melt pool flow during DLIP of stainless steel and aluminium is confirmed by experimental observations.

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Section: Introductionmentioning

confidence: 99%

An Incompressible Smoothed Particle Hydrodynamics (ISPH) Model of Direct Laser Interference Patterning

Demuth

Lasagni

2020

Computation

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“…The dominant pattern formation mechanism in this laser energy density regime is material transfer from the interference maxima to the minima positions (Marangoni effect). [34,35] This transfer of material is driven by the surface tension gradient caused by the induced temperature gradient in the material's surface. As a result, surface patterns develop due to material flow induced by the gradient.…”

Section: Direct Laser Interference Patterning Of 100cr6 Steelmentioning

confidence: 99%

“…DLIP allows the large area fabrication of periodic line-, cross-, and dot-like structures with feature sizes in the micro-and submicrometer length scale in a single step at high speeds (several square centimetres per second). [31][32][33][34][35][36] By controlling the angle between the interfering laser beams, periodic structures with different sizes and shapes can be fabricated under regular ambient conditions. The goal of the present work is to study the effects of DLIPgenerated surface structures on 100Cr6 bearing steel on the tribological properties, particularly friction, under lubricating conditions.…”

Section: Introductionmentioning

confidence: 99%

Ultra‐Low Friction on 100Cr6‐Steel Surfaces After Direct Laser Interference Patterning

et al. 2014

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This study discusses the effects of surface topographies on the frictional behavior of 100Cr6 bearing steel. A solid state laser with nanosecond pulses is used to produce one-and two-dimensional periodic micropatterns using direct laser interference patterning. Line-, cross-, and dot-like patterns with pitches of 5 mm, and aspect ratios (AR) between 0.02 and 0.17 are fabricated. The friction tests of the surface textured samples are performed under lubricating conditions using a ball-on-disk configuration in rotating mode. The results show that through the surface structure a reduction of the friction coefficient from 25 to 65% can be achieved compared to unstructured surfaces. The smallest coefficients of friction are obtained for ARs between 0.07 and 0.11.

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“…Demuth et al [36] simulated laser interference patterning of metallic surfaces using SPH, following Tong and Browne [37] who modelled laser spot welding of aluminium with a very primitive model and limited resolution. Gross's [24] model on laser cutting of metals was further developed by Muhammed et al [27] who simulated both dry and wet cutting of stainless steel stents used for medical applications, while Yan et al [38] modelled CO2 laser underwater machining of alumina ceramics.…”

Section: Introductionmentioning

confidence: 99%

Smoothed Particle Hydrodynamics (SPH) modelling of transient heat transfer in pulsed laser ablation of Al and associated free-surface problems

Alshaer

Rogers

2017

Computational Materials Science

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A smoothed particle hydrodynamics (SPH) numerical model is developed to simulate pulsed-laser ablation processes for micro-machining. Heat diffusion behaviour of a specimen under the action of nanosecond pulsed lasers can be described analytically by using complementary error function solutions of second-order differential equations. However, their application is limited to cases without loss of material at the surface. Compared to conventional mesh-based techniques, as a novel meshless simulation method, SPH is ideally suited to applications with highly nonlinear and explosive behaviour in laser ablation. However, little is known about the suitability of using SPH for the modelling of laser-material interactions with multiple phases at the micro scale. The present work investigates SPH modelling of pulsed-laser ablation of aluminium where the laser is applied directly to the free-surface boundary of the specimen. Having first assessed the performance of standard SPH surface treatments for functions commonly used to describe laser heating, the heat conduction behaviour of a new SPH methodology is then evaluated through a number of test cases for single-and multiple-pulse laser heating of aluminium showing excellent agreement when compared with an analytical solution. Simulation of real ablation processes, however, requires the model to capture the removal of material from the surface and its subsequent effects on the laser heating process. Hence, the SPH model for describing the transient behaviour of nanosecond laser ablation is validated with a number of experimental and reference results reported in the literature. The SPH model successfully predicts the material ablation depth profiles over a wide range of laser fluences 4-23 J/cm 2 and pulse durations 6-10 ns, and also predicts the transient behaviour of the ejected material during the laser ablation process. Unlike conventional mesh-based methods, the SPH model was not only able to provide the thermo-physical properties of the ejected particles, but also the effect of the interaction between them as well as the direction and the pattern of the ejection.2

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Thermal simulation of pulsed direct laser interference patterning of metallic substrates using the smoothed particle hydrodynamics approach

Cited by 19 publications

References 21 publications

An Incompressible Smoothed Particle Hydrodynamics (ISPH) Model of Direct Laser Interference Patterning

An Incompressible Smoothed Particle Hydrodynamics (ISPH) Model of Direct Laser Interference Patterning

Ultra‐Low Friction on 100Cr6‐Steel Surfaces After Direct Laser Interference Patterning

Smoothed Particle Hydrodynamics (SPH) modelling of transient heat transfer in pulsed laser ablation of Al and associated free-surface problems

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