Surface modification processes of aluminum alloys with readily fusible microadditions subjected to the treatment by high-power double laser pulses

The formation of the erosion plasma due to the effect of high-power double laser pulses (λ=1064 nm) on the surface of aluminum alloys containing readily fusible microadditions is studied experimentally by the atomic-emission multichannel spectrometry method using a LSS-1 laser atomic-emission multichannel spectrometer. It is demonstrated that the plasma chemical formation and erosion of the alloy surface may be controlled by varying both the energy of incident laser radiation and delay time of the second laser pulse. It is found that the processes of interaction between the radiation and alloy surface are considerably dependent on the method of varying the incident single-pulse power density. By way of example, when the incident radiation power density (λ=1064 nm, single-pulse width 15 ns) is changed due to variations in the pump energy (pump energy 10-15 J, radiation energy 10-50 mJ), evaporation rate of sodium is gradually increased. When using the mode of double laser pulses with the interpulse time interval from 1 to 10 μs, sodium is practically completely evaporated from the surface by several pulses. The results obtained are thoroughly discussed. (authors)