Техник ва технологик фанлар со
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аларининг инновацион масалалари. ТДТУ ТФ 2020
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aim of this work is to develop a technology for fabrication ordered micro holes array on
aluminum processed by pulsed laser radiation. In particular, study
of the influence of the
pulse duration and power, from the picosecond regime, on the formation of the holes shape
and depth during percussion drilling in aluminum is presented. The starting material for the
manufacture of picosecond laser drilled metal was used aluminum plates 4 x 4cm size and a
thickness of up to 2 mm. Before exposure
to pulsed laser irradiation, the metal surface was
ground and polished on a TM-1F Power Tool grinder machine. Then a sequential cleaning of
the metal surface was carried out in ultrasonic bath, first in ethanol and then deionized water,
respectively, for 10 minutes at room temperature. Next, the sample was dried in a drying
chamber for 3 hours at a temperature of 50 C. After sample preparation, in order to obtain a
micro-holes, the surface of aluminum samples was micro-drilled by picosecond lasers. The
UV laser source was 28 picosecond diode pumped Nd:YAG laser (PL2231-50, Ekspla,
Litvania) operating at the 4-th harmonic (UV line at λ =266 nm) within the pulse energy range
1,6 mJ at the repetition rate 50 Hz. The installation of laser shown in figure 1 (a). Achromatic
quartz lens with the focal length F = 75 mm was used for focusing. Interval between each
holes were 100 μm, laser treatment time duration per hole was 5 second, i.e. the number of
pulses per hole was around 250 pulses. Then samples after investigations
again fixed and
mechanical polished on a TM-1F Power Tool grinder machine, until obtaining mirrored
surface. In addition, sequential cleaning of the metal surface was carried out in ultrasonic
bath. A series of experiments were performed to examine the morphology, and composition
of laser-drilled surface of aluminum sample. Surface microstructure
of the metallic samples
was studied by optical microscopy using polarizing microscope Axlo Scope (AXIO) with
integrated digital camera AXIOCam ERc5S. The morphology of the sample before and after
anodizing was investigated using a scanning electron microscope SEM EVO MA 10 (Zeiss)
with energy dispersive X-ray spectroscopy EDS Aztec Energy Advanced X-Act (Oxford
Instruments) that used for local elemental analysis of samples. The microstructure of the
surface of the alumnium foil before irradiation with a pulsed laser is shown in Fig. 1 (b).
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