Changes in the Morphology and Strength Properties of the Vanadium Surface under the Influence of Helium Ions and Pulsed Laser Irradiation

Abstract

The effect of high-power pulsed laser irradiation generated in a GOS 1001 installation in the Q-switched mode (power density q = 1.2 × 1012 W/m2, pulse duration τ0 = 50 ns, number of pulses N = 1–4) in vacuum on a porous structure of the vanadium sample surface is studied, as well as on its hardness determined in two ways based on the recovered print method and on the kinetic indentation method. The porous structure is formed during implantation of helium ions (energy 30 keV, dose 2.0 × 1023 m–2, ion flux density 4.8 × 1018 m–2 · s–1, temperature ~500 K). It is shown that irradiation with helium ions causes vanadium hardening by about a factor of two, and the microhardness values determined by the recovered print method are slightly lower than the kinetic hardness values. It is found that in both cases, as a result of the target destruction under the laser radiation, a crater appears, surrounded by a breastwork, behind which there is a zone of thermal influence. Erosion is observed in this zone, caused by the destruction of the domes of bubbles-blisters filled with implanted helium and impurity atoms (C, O, N) present in the liquid metal. It is found that with an increase in the number of laser pulses, the microhardness in the crater decreases, while the narrow area around it hardens, and with further distance from the crater, the microhardness approaches values corresponding to that of vanadium implanted with helium ions.