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V. V. Ovchinnikov ¹, Yu. M. Borovin ¹, E. V. Lukianenko ¹, T. Yu. Skakova ¹, N. V. Uchevatkina ¹

Affiliations
1 Federal State Educational Institution of Higher Professional Education, Moscow State Industrial University, Moscow - 115280, RU

Abstract

Background/Objectives: Using electron microscopy, it was revealed that exposure to ion irradiation (Cu + Pb) with an energy of 35 keV of samples sized 25 × 25 × 3 mm of 1565ч industrial aluminum alloy after cold rolling, leads to a significant narrowing of the boundaries of intragranular cellular dislocation structure and increase in the extent of its regularity. Methods/Statistical Analysis: We have studied samples of 1565ч alloy sized 25 × 25 mm² cut from non-clad sheets of a thickness of 3 mm, a change in the structure of cold-worked 1565ч alloy exposed to the beams of accelerated ions (Cu + Pb) with an energy of 30 keV at the densities of ion current of 100, 200 and 300 μA/cm² and irradiation doses of 1016 and 1017 cm^-2. Irradiation with pulsed beams of ions (Cu + Pb) was conducted at the setup for ion beam implantation equipped with ion source based on plasma arc in vacuo. Electron microscopic study by the method of thin foils was conducted at JEM-2100 transmission electron microscope. Findings: It was found that irradiation of cold-worked clad 1565ч alloy with copper and lead ions does not lead to a fundamental change in its structure compared to the structure existing in the deformed condition: cellular dislocation structure remains. With increase in ion current density and irradiation dose, the cellular structure becomes more regular - well-formed cells are observed throughout almost the entire volume of the sample. The average width of dislocation-free regions reaches 2.5 μm at the width of the boundaries not exceeding 0.6 μm. The effect of accelerated ions (Cu + Pb) (E = 30 keV, j = 100 μA/cm²) on the alloy without the cladding layer even at a dose of 1016 cm^-2 leads to formation of the developed subgrain structure in initially deformed alloy. The average size of subgrains with interlacements of dislocations varies in the range of 0.6 - 2.2 μm. In other words, a polygonal structure forms in the alloy similar to the structure forming at the initial stages of recrystallization annealing. Applications/Improvements: This applies to many industries associated with the development of high-tech and energy-saving technologies as well as addressing environmental problems.

Keywords

Aluminum Alloy, Ion Implantation, Ions (Cu + Pb), Microstructure, Phase Composition.

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N. V. Uchevatkina ¹, Yu. M. Borovin ¹, V. V. Ovchinnikov ¹, O. A. Zhdanovich ¹, A. G. Sbitnev ¹

Affiliations
1 Federal State Educational Institution of Higher Professional Education, Moscow State Industrial University, Moscow - 115280, RU

Abstract

Background/Objectives: The article describes the results of the experimental measurement of the level of residual stresses in the surface layer of VT6 titanium alloy after ion implantation using polyion beams. Methods/Statistical Analysis: To study the effect of ion implantation on the residual stresses in the surface layer of VT6 titanium alloy, flat sheet samples of 1 mm thick and 10 mm wide were used. Before implantation the samples were annealed in a vacuum furnace to relieve stresses which arose during sheet rolling. The annealing temperature was 750 °C. Cathodes of copper, Cu-Pb monotectic alloy, and monotectic alloy with additional contact doping with tin were used. Findings: As a result of ion implantation in the studied range of doses of irradiation of VT6 titanium alloy, microstructure of its surface layer substantially hardens due to breakage of the particle size and the increase in the dislocation density. After implantation, it was managed to achieve the thickness of the modified layer comprising the actual implanted layer and the layer with changed dislocation structure of about 60...100 microns with an average size of nanoparticles near the surface of 50...100 nm. The dislocation density as a result of plastic deformation reached the values of ρD ≈ (2,7…9,8)·1012 (cm^-2) at the initial value ρDinit ≈ 5·1011 (cm^-2). The regularity of the increase in the residual compressive stresses at the increase in the implantation dose to 5·1017 ion/cm², and then with a further increase of the implantation dose, the residual stresses decrease. In general, the depth of occurence of the residual stresses slightly exceeds the depth of the implanted layer. Applications/Improvements: It is shown that by using beams with two and more ion kinds, residual stresses in the surface layer of VT6 titanium alloy increase.

Keywords

Ion Implantation, Mechanical Stresses, Multi-Element Ion Beams, Surface Layer, Titanium Alloys.

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