Search

The effect of 20-40 keV Ar+ ion irradiation on the mechanical properties and structural and phase state of hot-pressed profiles 6 mm thick made of an V95 alloy (Al-Zn-Mg-Cu system) after artificial aging has been studied. Irradiation (without causing heating) at fluences of 2∙1015 cm-2 and 1∙1016 cm-2 has been revealed to increase the relative elongation by 5%, without changing the strength characteristics. Electron microscopy examination has showed that irradiation has an effect on the state of the subgrain structure of the alloy. Irradiation at these fluences results in partial enlargement of the subgrain structure, and at higher fluence of 9.4∙1016 cm-2 it completely transforms the structure into coarse-grained one. At a distance of 150 µm from the irradiated surface, there is a slight increase in the subgrain size. The irradiation changes the morphology of Al6(Fe,Mn) intermetallic compounds in both the surface layer and the sample volume; namely, it sharply decreases the bulk density of lath-shaped intermetallic compounds and increases the density of the equiaxed ones. The degree of influence depend on the irradiation mode. © 2020 Institute of Physics Publishing. All rights reserved.

The effect of accelerated Ar+ ion beams with an energy of 10 keV on the microstructure and phase composition in 1469 alloy (Al-Cu-Li-Ag-Mg-Zr-Sc) initially subjected to severe plastic deformation (SPD) has been investigated by transmission electron microscopy. Irradiation has been found to result in the formation of a predominantly recrystallized nanocrystalline or fully recrystallized submicrocrystalline structure in the alloy, depending on the ion fluence. The irradiation liquidates the banded structure found in the alloy after SPD. Therefore, the structural elements (nanofragments, nanograins, submicrocrystals) are distributed uniformly in the volume of the irradiated sample. In addition, irradiation increases the volume fraction and the size bimodality of heterogeneously-generated Т2-phase particles. The mechanism of nucleation and growth of excess phases has been proposed. The structure changes at a higher rate than it does during a long low-temperature annealing process, and structural changes are observed at a distance of ~200 μm from the surface, which considerably exceeds the projected ion range (~ 10 nm). © 2020 Institute of Physics Publishing. All rights reserved.

The effect of Ar+ ion irradiation on structural and phase transformations in a 1461 alloy (Al-Li-Cu-Mg) subjected to megaplastic deformationhas has been studied by transmission electron microscopy. Short-term irradiation (E = 10 keV, F = 2 × 1016 cm-2) has been established to form a low-energy recrystallized submicrocrystalline structure at a depth (∼200 μm), significantly exceeding the projective ion ranges (∼10 nm). The study confirms the important role of the radiation-dynamic effect during the ion irradiation of metastable media. The structural and phase transformations take place in the alloy at a depth of much higher than the projective ion ranges and at a higher rate compared with traditional thermal annealing. © Published under licence by IOP Publishing Ltd.

The effect of 20-40-keV Ar+ ion irradiation on the fatigue resistance of hot-pressed V95 alloy (Al-Zn-Mg-Cu system) profiles 6 mm thick after quenching and artificial aging (140°, 16 h) has been investigated. The use of the irradiation conditions (E = 40 keV, j = 500 μA/cm2), under which the profiles were briefly heated to a temperature of 200°C, is found to reduce the strength properties of the alloy significantly, which does not meet the specified requirements. Irradiation conditions, which enable one to avoid significant heating of a target at E = 20 keV and j = 400 μA/cm2, do not affect the fatigue resistance significantly at all fluences of F = 1•1015, 1•1016, 1•1017 cm-2. © 2019 IOP Publishing Ltd. All rights reserved.

The effect of Ar+ ion irradiation and subsequent prolonged aging on the microstructure and phase transformations in a B-1461 alloy (Al-Cu-Li-Zn-Mg-Zr-Sc) subjected to megaplastic deformation (MPD) has been studied by transmission electron microscopy. A mixed structure, consisting of nanocrystalline and nanofragmented regions has been found to form in the alloy upon MPD. Subsequent short-term Ar+ ion irradiation (E = 20 keV, j = 300 μA•cm-2, F = 1.9?1015 cm-2) forms dislocation tangles, increases the nonuniform distribution and the size of structural elements, as well as volume fraction of a T2-phase (Al3CuLi5) nano and submicrocrystals heterogeneously nucleated at boundaries. Structural changes are observed at a distance of ∼ 200 μm from the surface, which considerably exceeds the projective ion range (∼ 20 nm). The structure of the B-1461 alloy after MPD and subsequent irradiation under the above conditions is unstable. © 2019 IOP Publishing Ltd. All rights reserved.

The effect of 10-keV Ar+ ion irradiation on the mechanical properties and structural and phase state of hot-pressed thin profiles 1.5 mm thick and made of an V95 alloy (Al-Zn-Mg-Cu system) after artificial aging (T = 140?C, 16 h) has been studied. Ion beam treatment of the alloy (j = 300 μA•cm-2, F = 1.9•1015 and 1.1•1016 cm-2) without heating the samples to significant temperatures (T < 35-50?C) has not been established to change the ultimate strength and yield strength; however, it increases the relative elongation by 1-2 %. Transmission electron microscopy has shown that irradiation changes the grain structure and the morphology of particles of the crystallization origin in the entire volume of quenched and artificially aged V95 alloy samples (1.5 mm thick). The irradiation does not affect the size and the volume fraction of fine strengthening η′- and η-phase particles. © 2019 IOP Publishing Ltd. All rights reserved.