engleski

High-Power Laser-Metal Interactions in Pressurized Gaseous Atmospheres

Metal surfaces (Ti, Ta, Mo) were irradiated in pressurized gaseous atmospheres by a CO2 laser beam. The gaseous pressures ranged from 2 atm to 6 atm, the energy density of the light beam was about 20-50 J/cm2 with a power density about 10(9) W/cm2 and a pulse duration about 150 ns.In the above conditions some effects were observed. The laser-metal interaction occurred in a highly absorptive plasma regime, meaning that the metal surface was effectively screened from the beam. The interaction ended either with plasma adiabatic expansion, in the case of Mo (in O2), Ta (inN2) and Ti (in N2), or with plasma explosion, in the case of Ti (in O2). The metal surface properties were studied by means of optical analysis, microhardness tests, X-ray diffraction and Raman scattering

Laser-metal interactions; Pressurized gaseous (N2; O2) atmospheres; Metal surfaces (Mo; Ta; Ti); Light microscopic observations; Microhardness tests; X-ray diffraction; Raman backscattering.

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