scholarly journals Предпороговые эффекты при воздействии ультрафиолетовых лазерных импульсов на медь и ее сплавы

2022 ◽  
Vol 92 (2) ◽  
pp. 268
Author(s):  
Т.В. Малинский ◽  
В.Е. Рогалин
Keyword(s):  
Plastic Deformation ◽  
High Temperature ◽  
Laser Radiation ◽  
Energy Density ◽  
Grain Boundaries ◽  
Radiation Energy ◽  
Condensed State ◽  
Laser Radiation Energy ◽  
Radiation Energy Density ◽  
Accumulation Of Damage

The prethreshold processes on the surface of copper and its alloys are investigated. In the absence of obvious traces of melting, while preserving the metal in a condensed state, under a nanosecond ultraviolet laser radiation energy density of 0.1–1.0 J/cm2, manifestations of high-temperature plastic deformation were observed. These are sliding and cracking along grain boundaries, within which crystallographic slipping was observed. A microprotrusion was formed on the surface of the irradiated zone, which was outwardly similar the distribution of laser radiation in the spot. The height of the microprotrusion reached 1 µm, and sometimes even more. An increase in the number of impacting impulses led to the accumulation of damage. The data obtained are in many ways similar to the acoustoplastic, electroplastic, and magnetoplastic effects. By analogy, we consider it possible to call the discovered effect optoplastic.

Features of Brass Processing with Powerful Ultraviolet Lasers of Nanosecond Duration

2022 ◽  
Vol 1049 ◽  
pp. 11-17
Author(s):  
Ivan Kaplunov ◽  
Taras Malinskiy ◽  
S.I. Mikolutskiy ◽  
Vladimir Rogalin ◽  
Yuriy Khomich ◽  
...  
Keyword(s):  
Energy Density ◽  
Metal Structure ◽  
Radiation Energy ◽  
Laser Heat Treatment ◽  
Absorbed Energy ◽  
Radiation Energy Density ◽  
Nanosecond Duration ◽  
Third Harmonic ◽  
Accumulation Of Damage ◽  
Ultraviolet Lasers

We investigated the process of laser heat treatment of polished brass samples (36% zinc, containing a small amount of lead, which does not dissolve in the alloy and is in the form of inclusions, having micron and submicron size) by impacting to a series of 25 - 30 ultraviolet (UV) pulses of a Nd:YAG laser (third harmonic, wavelength λ = 355 nm, duration τ = 10 ns, pulse repetition rate f = 10 Hz, pulse energy density ~ 0.15 - 1.0 J/cm2) in the stationary spot mode. Copper and its alloys absorb up to 90% of the energy of this laser. It is found that the relaxation of the absorbed energy of laser radiation in the metal occurs nonuniformly. Defects in the metal structure such as grain boundaries and lead inclusions are visualized. Traces of crystallographic sliding appear inside some grains. With an increase in the number of impacting impulses, accumulation of damage is observed. A further increase in the radiation energy density leads to an aggravation of the observed phenomena.

Ponderomotive pressure effects in laser driven high-temperature plasma flows

1981 ◽  
Vol 25 (2) ◽  
pp. 193-213 ◽  
Author(s):  
J. L. Bobin
Keyword(s):  
High Temperature ◽  
Mach Number ◽  
Energy Density ◽  
Density Ratio ◽  
Radiation Energy ◽  
Pressure Effects ◽  
Initial State ◽  
Temperature Plasma ◽  
Radiation Energy Density ◽  
Plasma Effects

Gasdynamical equations taking radiation energy density and ponderomotive pressure into account are investigated. Conditions for these quantities to be important are stated: low absorption, reflexion at cut-off. The density ratio in a discontinuity is studied as a function of ponderomotive pressure, absorbed intensity and Mach number in the initial state. Chapman–Jouguet conditions are defined. Compressive (R type) flows and rarefaction (D type) appear. The structure of the latter is discussed including plasma effects.

scholarly journals On modeling the problems of high-temperature radiation gas dynamics

1984 ◽  
pp. 1-17
Author(s):  
Vladimir Yakovlevich Gol’din ◽  
Dinamika Alekseevna Gol'dina ◽  
Andrey Vasilievich Kolpakov ◽  
Alexander Victorovich Shilkov
Keyword(s):  
High Temperature ◽  
Energy Density ◽  
Numerical Methods ◽  
Mathematical Models ◽  
Gas Dynamics ◽  
Radiation Energy ◽  
High Radiation ◽  
Radiation Energy Density ◽  
Temperature Radiation ◽  
Radiation Gas Dynamics

Mathematical models of High-Temperature Radiation Gas Dynamics (HTRGD) are considered. The possibility of instability of contact boundaries at a high radiation energy density is shown. Equations of the three-temperature approximation are consistently derived. Numerical methods for solving the problems of HTRGD are discussed.

scholarly journals Electrically conductive CNT networks formed by laser

2021 ◽  
Vol 2086 (1) ◽  
pp. 012011
Author(s):  
A V Kuksin ◽  
U E Kurilova ◽  
O E Glukhova ◽  
E M Eganova ◽  
A A Dudin ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Energy Density ◽  
Porous Materials ◽  
Experimental Studies ◽  
Radiation Energy ◽  
Radiation Energy Density ◽  
Electrically Conductive ◽  
Pore Sizes

Abstract Materials containing conductive CNT networks were investigated in this work. Binding of CNTs to each other was carried out using laser radiation in scanning mode. As a result of experimental studies, radiation energy density at which the effect of SWCNT binding occured was found – 0.061 J/cm2. Mechanism by which formation of porous materials with SWCNTs in composition takes place has been established. Materials from CNTs and biopolymers with controllable pore sizes that make up more than 60% of nanocomposite volume have been made.

scholarly journals The accumulation of femtosecond laser radiation energy in crystals of lithium fluoride

2015 ◽  
Author(s):  
V. P. Dresvyanskiy ◽  
D. S. Glazunov ◽  
S. V. Alekseev ◽  
V. F. Losev ◽  
B. Chadraa ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Femtosecond Laser ◽  
Lithium Fluoride ◽  
Radiation Energy ◽  
Femtosecond Laser Radiation ◽  
Laser Radiation Energy

Measurement facility for the relative radiation energy density distribution for pulse-periodic lasers

1988 ◽  
Vol 31 (10) ◽  
pp. 966-967
Author(s):  
V. I. Andreev ◽  
A. P. Palivoda ◽  
S. P. Fetisov ◽  
N. V. Shalomeeva ◽  
V. A. Yakovlev
Keyword(s):  
Energy Density ◽  
Density Distribution ◽  
Radiation Energy ◽  
Measurement Facility ◽  
Radiation Energy Density ◽  
Energy Density Distribution

SOLAR PUMPED LASER BASED ON COMPOSITE TITANIUMSAPPHIRE ACTIVE MEDIUM

2018 ◽  
Vol 20 (5) ◽  
pp. 321-323
Author(s):  
Sh. Payziyev ◽  
Kh. Makhmudov ◽  
S. Bakhramov ◽  
A. Kasimov
Keyword(s):  
Laser Radiation ◽  
Pump Power ◽  
Solar Radiation ◽  
Solar Energy ◽  
Computer Simulations ◽  
Active Element ◽  
Radiation Energy ◽  
Laser Radiation Energy ◽  
Optimal Geometry ◽  
Concentrated Solar Radiation

On the basis of the active element of Ti3+:Al2O3, the possibility of converting solar energy into laser radiation energy is investigated. By the computer simulations, it was shown the possibility of reducing the threshold pump power by choosing the optimal geometry of the crystal parameters for end-pumping scheme of concentrated solar radiation.

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