An analytical modeling of time dependent pulsed laser melting

Tokarev, V. N.; Kaplan, Alexander

doi:10.1063/1.371132

Cited by 55 publications

(30 citation statements)

References 26 publications

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“…Various descriptions of melting, resolidification, surface vaporization, and ablation can be incorporated into such models, albeit at a rather simplified level. In particular, laser melting and resolidification are often described with a phase-change model based on an assumption of local equilibrium at the solid-liquid interface (heat-flow limited, interface kinetics formulated within the framework of the Stephan problem), e.g., [37][38][39], or using a kinetic equation relating the interface velocity to the interface temperature, e.g., [40][41][42][43][44]. The latter nonequilibrium kinetic description has been shown to be necessary for subnanosecond pulses, when a fast thermal energy flow to/from the liquid-solid interface creates conditions for significant overheating/undercooling of the interface [43,44].…”

Section: Introductionmentioning

confidence: 99%

Atomic/Molecular-Level Simulations of Laser–Materials Interactions

Zhigilei

Lin

Ivanov

et al. 2009

Laser-Surface Interactions for New Materials Production

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Summary. Molecular/atomic-level computer modeling of laser-materials interactions is playing an increasingly important role in the investigation of complex and highly nonequilibrium processes involved in short-pulse laser processing and surface modification. This chapter provides an overview of recent progress in the development of computational methods for simulation of laser interactions with organic materials and metals. The capabilities, advantages, and limitations of the molecular dynamics simulation technique are discussed and illustrated by representative examples. The results obtained in the investigations of the laser-induced generation and accumulation of crystal defects, mechanisms of laser melting, photomechanical effects and spallation, as well as phase explosion and massive material removal from the target (ablation) are outlined and related to the irradiation conditions and properties of the target material. The implications of the computational predictions for practical applications, as well as for the theoretical description of the laser-induced processes are discussed. IntroductionShort-pulse lasers are used in a diverse range of applications, from advanced materials processing, cutting, drilling, and surface micro-and nanostructuring [1,2] to pulsed-laser deposition of thin films and coatings [3], laser surgery [4,5], and artwork restoration [6,7], and to the exploration of the conditions for inertial confinement fusion, with the world's most energetic laser system being built at the National Ignition Facility at Lawrence Livermore National Laboratory [8]. At the fundamental science level, short-pulse laser irradiation has the ability to bring material into a highly nonequilibrium state and provides a unique opportunity to probe the material behavior under extreme conditions. In particular, optical pump-probe experiments have been used to investigate transient changes in the electronic structure of the irradiated surface with high (often subpicosecond) temporal resolution [9][10][11][12][13], whereas recent advances in time-resolved X-ray and electron diffraction

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Section: Introductionmentioning

confidence: 99%

Atomic/Molecular-Level Simulations of Laser–Materials Interactions

Zhigilei

Lin

Ivanov

et al. 2009

Laser-Surface Interactions for New Materials Production

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“…To explore the mechanisms responsible a simple laser heating model 18 was used to explain the behavior of the plasma shutter. The model assumes heating of a semi-infinite, homogeneous, and isotropic metallic sample by a laser pulse with a rectangular (i.e., top-hat) temporal profile.…”

Section: Resultsmentioning

confidence: 99%

“…The model assumes heating of a semi-infinite, homogeneous, and isotropic metallic sample by a laser pulse with a rectangular (i.e., top-hat) temporal profile. Solving the heat conduction equation 18,19 gives an analytic expression for the temperature distribution during the laser pulse, inside the metal target, T(z,t) as…”

Section: Resultsmentioning

confidence: 99%

CO2 laser pulse shortening by laser ablation of a metal target

Donnelly

Mazoyer²,

Lynch³

et al. 2012

Review of Scientific Instruments

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A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO2 laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to ∼2 ns and to remove the low power, long duration tails that are present in TEA CO2 pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is ∼10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.

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“…Perry et al [1][2][3] used a one-dimensional finite element model to simulate melting due to a single laser pulse in which it was assumed that [20] χ t pulse << r 2 (9) where χ is the thermal diffusivity, t pulse is the laser pulse duration, and r is the laser spot radius. The ability of this one-dimensional model to accurately estimate t m-max diminishes at higher pulse durations.…”

Section: B Heat Transfer Modelmentioning

confidence: 99%

Pulsed laser micro polishing: Surface prediction model

Vadali

Duffie

et al. 2012

Journal of Manufacturing Processes

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This project is focused on developing physics-based models to predict the outcome of pulsed laser micro polishing (PLµP). Perry et al. [1][2][3] have modeled PLµP as oscillations of capillary waves with damping resulting from the forces of surface tension and viscosity and a one-dimensional spatial frequency domain analysis was proposed. They have also proposed a critical spatial frequency, f cr , above which a significant reduction in the amplitude of the spatial Fourier components is expected. The current work extends the concept of critical frequency to two dimensional spatial frequency analysis of PLµP. We propose a physics-based prediction methodology to predict the spatial frequency content and surface roughness after polishing, given the features of the original surface, the material properties, and laser parameters used for PLµP.The proposed prediction methodology was tested using PLµP line polishing data for stainless steel 316L and area polishing results for pure Nickel, Ti6Al4V, and Al-6061-T6. The predicted average surface roughnesses were within 10% to 12% of the values measured on the polished surfaces. The results show that the critical frequency continues to be a useful predictor of polishing results in the 2-D spatial frequency domain. The laser processing parameters, as represented by the critical frequency, and the initial surface texture can be used to predict the final surface roughness before actually implementing PLµP.

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An analytical modeling of time dependent pulsed laser melting

Cited by 55 publications

References 26 publications

Atomic/Molecular-Level Simulations of Laser–Materials Interactions

Atomic/Molecular-Level Simulations of Laser–Materials Interactions

CO2 laser pulse shortening by laser ablation of a metal target

Pulsed laser micro polishing: Surface prediction model

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