Features of Damageability and Modification of Surface Layers of Al and Its Alloys by Powerful Energy Fluxes in a Plasma Focus Facility

• Published in: Inorganic materials : applied research 2022-04, Vol.13 (2), p.365-377
• Main Authors: Pimenov, V. N., Maslyaev, S. A.
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum base alloys; Aluminum oxide; Ceramic coatings; Chemistry; Chemistry and Materials Science; Composition; Crystal lattices; Crystallization; Deuterium; Deuterium plasma; Duralumin; Fluxes; High temperature plasmas; Inclusions; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Irradiation; Lithium; Magnesium oxide; Materials for Energetics and Radiation-Hardened Materials; Materials Science; Plasma; Plasma focus; Pulse duration; Pulsed lasers; Radiation; Solid solutions; Structural stability; Substrates; Superconductors (materials); Surface layers
• ISSN: 2075-1133; 2075-115X
• DOI: 10.1134/S2075113322020332

The results of the analysis of damageability and modification of the structural-phase state of the surface layers of aluminum and its alloys by powerful fluxes of fast high-energy ions and high-temperature plasma in plasma focus facilities as well as using pulsed laser radiation are presented. Pure Al, an alloy of the Al–Mg–Li system, a duralumin alloy, and a composition of a ceramic coating Al 2 O 3 on an Al substrate are considered. It is shown that, in the regime of Al irradiation with a power density of q ≈ 10 6 –10 7 W/cm 2 in the nano- and microsecond range of pulse durations, ultrafast crystallization of melted surface layer occurs with the formation of a wavy surface relief and structural fragments of submicrocrystalline and nanoscale size. After the action of deuterium plasma fluxes on a duralumin alloy tube located along the axis of the plasma focus facility, a modification of the structural-phase state of the alloy is observed: the initial two-phase state of an α Al -solid solution of copper in aluminum and inclusions of the second phase of CuAl 2 became fine-grained and single-phase owing to the dissolution of CuAl 2 particles in the melt. Irradiation of an alloy of the Al–Mg–Li system containing 2 wt % Li and 5 wt % Mg at q = 5 × 10 6 W/cm 2 and τ = 50–100 ns after four pulsed impacts of fast ions and deuterium plasma led to the modification the structural-phase state of the surface layer of the alloy associated with an increase in the content of magnesium oxide and a decrease in the crystal lattice parameter of the Al-based solid solution. The formation of spherical cavities due to the evaporation of lithium into the internal micropores of the surface layer is also found. The low damageability and structural stability of Al 2 O 3 ceramic on an Al substrate under beam-plasma impacts in the plasma focus facility with a radiation power density q ≤ 10 8 –10 9 W/cm 2 in the nano- and microsecond range of pulse duration is noted. At the same time, the Al 2 O 3 /Al composition was unstable to pulsed laser radiation in the free-running mode ( q = 10 5 –10 6 W/cm 2 , τ = 0.7 ms) and Q-switch mode ( q = 10 7 –10 8 W/cm 2 , τ = 80 ns). In both cases, the coating peeled off from the substrate.