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In this work, the characteristics of surface morphology and structure of experimental samples of nickel-based alloy and copper nozzles manufactured by the electron beam additive method have been studied. It is found that the grain boundaries on the outer sample surface are oriented at different angles relative to the substrate due to uneven heat dissipation during printing. It is found that 3D printing in a non-optimal temperature regime produces a highly heterogeneous structure within the material layer. A curvilinear boundary zone is observed in which different structural phase components are formed, including solid solutions and mechanical mixtures. [ABSTRACT FROM AUTHOR]

The influence of tensile stress on the interface structure of functionally gradient materials is studied in a stainless steel-copper composite fabricated using a wire-feed electron beam technology. A distinct boundary is observed between the two materials, with the two-phase transition regions formed on both sides of the interface. The mechanical tests demonstrate an important role of the interface orientation during the plastic deformation development under uniaxial tensile loading. In the case of the longitudinal and diagonal interfaces, copper and steel simultaneously undergo plastic deformation. The fracture surface also reveals the presence of heterogeneous regions. In the orthogonal interface, necking and subsequent rupture occur in milder copper. However, its mechanical properties are found to be better compared to those of the additively grown copper. [ABSTRACT FROM AUTHOR]

The features of structure formation and properties of bronze-steel composite samples formed by wire-feed electron beam additive manufacturing are studied. The studies show that at the bronze-to-steel ratio of 1:1 quite homogeneous structure is formed in them, with dendritic steel fragments and bronze filling the interdendritic space. When fabricated at the optimum process parameters, the samples do not contain any pores, inclusions, discontinuities or delamination. The strength characteristics of the resulting composites significantly exceed those of the base pure bronze. The mechanical properties of the samples are very similar in the compression and build direction. The yield strength values, calculated based on the contributions from different phases, differ from the measured values by up to 20%. [ABSTRACT FROM AUTHOR]

The defect formation and the structure inhomogeneities of composite material samples made from aluminummanganese bronze with various strengthening components added during electron beam printing are studied. The results show a complex and diverse nature of interactions between the components during the electron beam printing of polymetallic systems differing in their structure and composition. The main defects are the pores formed in some cases during optimization of the printing modes. The other defects are the areas of mutually mixed material components formed at the substrate–sample interface, which affect the structure and properties of the resulting products. The components are stirred down to a depth of 10–15 mm from the substrate inwards the sample. The structure and composition inhomogeneities, caused by differing melting temperatures and densities of the components, are most numerous. The formation of these inhomogeneities generally correlates with the material layers deposited on the substrate and does not cause appreciable changes in the mechanical properties of the resulting materials. [ABSTRACT FROM AUTHOR]

The regularities of formation of composite materials from CuAl9Mn2 bronze and 9MnSi5 steel by wire-feed electron beam additive manufacturing are reported. It is shown that an introduction of the strengthening phases of a material with a higher melting point (9MnSi5) into the material with a lower melting point (CuAl9Mn2) results in the formation of strengthening phases with dendritic structure uniformly distributed in the material volume. In the cases where a material with a higher melting point (9MnSi5) is fed into the material with a lower melting point (CuAl9Mn2), an inhomogeneous structure is formed, containing a number of defects of various shapes and sizes. The mechanical properties of the samples of the first type are characterized by an increased strength and plasticity compared to the base metal. The structure of the samples of the second type contains numerous defects, which in some cases sharply deteriorates their mechanical properties. The chemical composition of the sample components and their distributions in the samples vary from layer to layer. [ABSTRACT FROM AUTHOR]

In the present work, mechanical and tribological investigations of samples based on Cu–Fe system with different amounts of austenitic steel in the copper matrix have been carried out. By the method of electron-beam wire additive technology, samples of metal matrix composites have been obtained from heterogeneous materials with introduction at printing of 10, 25, 36 and 50% of steel 321 in the matrix of copper C11000. In the work, essential orientation dependence of mechanical and tribological behavior of samples is established. For samples the friction plane of which was located longitudinal to layers, fast growth of wear intensity at increase in the content of copper has been revealed. It occurs due to the lesser role of friction adhesion and plastic displacement of the sample material from the friction contact zone. It is revealed that at increase of the volume fraction of steel introduced into the copper matrix, there is a limit in hardening of composite material. At introduction of more than 25% of steel, the mechanical properties of the material change sufficiently weakly. Changes of the mechanical properties of materials at increase of the steel content up to 50% consist in essential growth of plasticity. At tribological tests, the essential decrease in average coefficient of friction and wear is revealed at samples with steel content of 50%, the friction plane of which has been located transvese to the applied layers. For all samples, the wear resistance was higher than that of additive samples of pure copper. [ABSTRACT FROM AUTHOR]

The regularities of structure formation and operational properties of bimetallic functionally graded samples made of nickel-based Udimet500 and bronze CuCr1 have been investigated. The results of obtaining samples with different order of deposited layers on the substrate were obtained. It was found that deposition of nickelbased superalloy on copper alloy forms a gradient zone of less thickness than deposition of copper alloy on nickel-based superalloy. The structure of the transition zone is characterized by a division into a region of mechanical mixing of the components and a region with a smoothly changing composition, extending to the pure alloy. The extended smooth gradient zone is characteristic of the component deposited in the top part of the sample, and the boundary with the component located in the bottom part is sharp. The mechanical properties of the gradient zone of the samples are at the level of the least strong component, bronze CuCr1. Tensile rupture of the samples occurs along the bronze area. [ABSTRACT FROM AUTHOR]

The paper studies Ti-6Al-4V alloy specimens obtained by wire-based electron-beam additive manufacturing (EBAM) and characterized by the structure with a defective region produced by uncontrolled wire fluctuations during 3D printing. Metallographic analysis and tensile strength tests and microhardness measurements are conducted to determine the defect influence on the structure and properties of the alloy. It is shown that the defective region represents the primary β-phase grains that are finer than those of the EBAM specimens commonly exhibiting a columnar structure. The specimen microhardness both in the defective and defect-free regions, is identical. The deformation behavior of the alloy is mostly subject to the influence of such defects, since the plasticity and ultimate tensile strength of the defective region are respectively higher and lower than that of the defect-free region. [ABSTRACT FROM AUTHOR]

The paper is devoted to studying two different ways of obtaining the complex-shaped bell-type samples from the titanium alloy Ti-6Al-4V. It is shown that the process of obtaining the samples on a three-axis table is sensitive to the wire feed geometry as depended on four such geometry zones. These zones are characterized by the angles between the wire feed direction and the tangent to the printing path. On the contrary, samples obtained on a rotary four-axis table are not sensitive to the wire feed geometry. Each of the two ways provides formation of its own specific types of the structure and different mechanical characteristics. In this paper, the structure of geometry affected zones is determined and the most optimal way for obtaining the samples is selected. [ABSTRACT FROM AUTHOR]