Laser thermoelastic generation in metals above the melt threshold

A. G. Every, Z. N. Utegulov, I. A. Veres

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    An approach is presented for calculating thermoelastic generation of ultrasound in a metal plate exposed to nanosecond pulsed laser heating, sufficient to cause melting but not ablation. Detailed consideration is given to the spatial and temporal profiles of the laser pulse, penetration of the laser beam into the sample, the appearance and subsequent growth and then contraction of the melt pool, and the time dependent thermal conduction in the melt and surrounding solid throughout. The excitation of the ultrasound takes place during and shortly after the laser pulse and occurs predominantly within the thermal diffusion length of a micron or so beneath the surface. It is shown how, because of this, the output of the thermal simulations can be expressed as axially symmetric transient radial and normal surface force distributions. The epicentral displacement response to these force distributions is obtained by two methods, the one based on the elastodynamic Green's functions for plate geometry determined by the Cagniard generalized ray method and the other using a finite element numerical method. The two approaches are in very close agreement. Numerical simulations are reported on the epicentral displacement response of a 3.12 mm thick tungsten plate irradiated with a 4 ns pulsed laser beam with Gaussian spatial profile, at intensities below and above the melt threshold.

    Original languageEnglish
    Article number203508
    JournalJournal of Applied Physics
    Volume114
    Issue number20
    DOIs
    Publication statusPublished - Nov 28 2013

    Fingerprint

    force distribution
    pulsed lasers
    laser beams
    thermal simulation
    elastodynamics
    metal plates
    thresholds
    laser heating
    thermal diffusion
    profiles
    diffusion length
    pulses
    metals
    ablation
    contraction
    lasers
    rays
    tungsten
    Green's functions
    penetration

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

    Cite this

    Laser thermoelastic generation in metals above the melt threshold. / Every, A. G.; Utegulov, Z. N.; Veres, I. A.

    In: Journal of Applied Physics, Vol. 114, No. 20, 203508, 28.11.2013.

    Research output: Contribution to journalArticle

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