7 September 1994 Nonstationary plasma-thermo-fluid dynamics and transition in processes of deep penetration laser beam-matter interaction
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Proceedings Volume 2207, Laser Materials Processing: Industrial and Microelectronics Applications; (1994) https://doi.org/10.1117/12.184732
Event: Europto High Power Lasers and Laser Applications V, 1994, Vienna, Austria
Abstract
A qualitative analysis of the role of some hydrodynamic flows and instabilities by the process of laser beam-metal sample deep penetration interaction is presented. The forces of vapor pressure, melt surface tension and thermocapillary forces can determined a number of oscillatory and nonstationary phenomena in keyhole and weld pool. Dynamics of keyhole formation in metal plates has been studied under laser beam pulse effect ((lambda) equals 1.06 micrometers ). Velocities of the keyhole bottom motion have been determined at 0.5 X 105 - 106 W/cm2 laser power densities. Oscillatory regime of plate break- down has been found out. Small-dimensional structures with d-(lambda) period was found on the frozen cavity walls, which, in our opinion, can contribute significantly to laser beam absorption. A new form of periodic structure on the frozen pattern being a helix-shaped modulation of the keyhole walls and bottom relief has been revealed. Temperature oscillations related to capillary oscillations in the melt layer were discovered in the cavity. Interaction of the CW CO2 laser beam and the matter by beam penetration into a moving metal sample has been studied. The pulsed and thermodynamic parameters of the surface plasma were investigated by optical and spectroscopic methods. The frequencies of plasma jets pulsations (in 10 - 105 Hz range) are related to possible melt surface instabilities of the keyhole.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Vladimir S. Golubev, Vladimir S. Golubev, Alexander F. Banishev, Alexander F. Banishev, V. V. Azharonok, V. V. Azharonok, Alexandre M. Zabelin, Alexandre M. Zabelin, } "Nonstationary plasma-thermo-fluid dynamics and transition in processes of deep penetration laser beam-matter interaction", Proc. SPIE 2207, Laser Materials Processing: Industrial and Microelectronics Applications, (7 September 1994); doi: 10.1117/12.184732; https://doi.org/10.1117/12.184732
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