40 research outputs found

    Complex research on the interaction of glass with space debris

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    This paper discusses the interactions of barriers with a spherical impactor and the character of possible deformation and fragmentation of barriers and impactors. The destruction of glass is considered as a process of destruction of fragile material without a part of plastic deformation characteristic of the deformation metals. To calculate the elastic-plastic flow a technique was used which was implemented on the tetrahedral cells and based on the combined use of the Wilkins method for calculating the interior points of the body and the Johnson method for calculating contact interactions. Methods for accelerating the flow of fine particles and the individual spherical particles have been developed. A series of experiments for usual glass and glass with coatings has been carried out

    Grain size effect on yield strength of titanium alloy implanted with aluminum ions

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    The paper presents a transmission electron microscopy (TEM) study of the microstructure and phase state of commercially pure titanium VT1-0 implanted by aluminum ions. This study has been carried out before and after the ion implantation for different grain size, i.e. 0.3 µm (ultra-fine grain condition), 1.5 µm (fine grain condition), and 17 µm (polycrystalline condition). This paper presents details of calculations and analysis of strength components of the yield stress. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress. So, both before and after the ion implantation, the increase of the grain size leads to the decrease of the alloy hardening. Thus, hardening in ultra-fine and fine grain alloys increased by four times, while in polycrystalline alloy it increased by over six times

    Hardening by ion implantation of VT1-0 alloy having different grain size

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    The paper presents a transmission electron microscopy (TEM) study of the structural and phase state of commercially pure titanium implanted by aluminum ions. TEM study has been carried out for two types of grains, namely coarse (0.4 µm) and small (0.5 µm). This paper presents details of the yield stress calculations and the analysis of strength components for the both grain types in two areas of the modified layer: at a distance of 0-150 nm (surface area I) and ∼300 nm (central area II) from the irradiated surface. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress in areas I and II. Thus, near the ion-alloyed layer, the yield stress decreases with the increase of the grain size, whilst area II demonstrates its increase. Moreover, the contribution to the general hardening of the alloy made by certain hardening mechanisms differs from contributions made by each of these mechanisms in each certain case

    Modification of structural phase state and mechanical properties of poly-grained titanium alloy implanted by aluminum ions

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    The paper presents TEM analysis of microstructure, phase composition, and mechanical properties of commercially pure titanium. These properties of two types of grains are compared before and after modification of titanium by aluminum ions, namely: large grains (1.4 μm) and small (0.5μm) grains. The analysis shows that ion implantation results in a considerable improvement of mechanical properties of both large and small grains throughout their implantation depth. However, with increase of the grain size, the stress in the ion-modified surface layer decreases while in the subsurface layer it increases
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