Materials Science Forum Vol. 1037

Abstract: The paper investigates the features of deformation and fracture of steels obtained using the technology of 3D printing by electric arc surfacing based on the registration of the acoustic emission signal. With a decrease in the test temperature of 07Cr25Ni13 steel, a decrease in the work expended in stretching the specimen is observed, both at the stage of elastic deformation and at the stage of strain hardening. It was found that the most informative characteristic parameters of the AE signal include: the pulse count rate N, the total count NΣ, and the AE signal entropy. With a decrease in the test temperature, there is a significant increase in the intensity of the AE signal, the total number of pulses at all stages of deformation and destruction of steel. The obtained regularities of changes in the characteristic parameters of the AE signal can be used as diagnostic features, both in assessing the stage of deformation and destruction of the material, and the structural state of the material. Fractographic studies have shown a significant decrease in the tough component of 08Mn2Si steel with a decrease in the test temperature. The fracture mechanisms of 07Cr25Ni13 steel change insignificantly with decreasing temperature, however, a significant decrease in the ductility of the metal is observed, as evidenced by a decrease in the size of ductile fracture cups.

Abstract: The development of additive manufacturing requires the improvement of 3D printers to increase accuracy and productivity. Delta kinematics 3D printers have advantages over traditional sequential kinematics 3D printers. The main advantage is the high travel speed due to the parallel movement of the platform from three pairs of arms. Another advantage is the relatively low cost due to the small number of structural components. However, delta 3D printers have received limited use. The main reason is the low positioning accuracy of the end effector. Errors in the manufacture and assembly of components of a parallel drive mechanism add up geometrically and cause an error in the position of the end effector. These formulas can be applied to a 3D printer as well. However, well-known studies consider deterministic models. Therefore, the analysis is performed for limiting size errors. The purpose of this article is to simulate the effect of statistical errors in displacements and arm lengths on the positioning errors of a platform with the end effector. The article effectively complements the field of error analysis research and provides theoretical advice on error compensation for delta 3D printer.

Abstract: This paper considers a novel approach for integration between molecular engineering of XNA-based structures and additive manufacturing of XNA-based devices based on multiparametric characterization of XNAs by different functional descriptors (such as physical properties of XNA-based materials and precursors of XNA-based molecular devices) and the possibility of thermal or electron-beam processing as a prerequisite of the industrial technical process development for such device implementation. This can be performed in the framework of additive manufacturing by connecting the output of the XNA synthesizer or nucleic acid synthesizer with 3D-printer nozzles in such a way that oligos / AGCTX products are supported into the nozzles separately.

Abstract: This work presents the results of work on a 3D printing device with a non-standard arrangement of the table and nozzle, which is necessary for the additive production of plastic cases for electronic devices. The non-standard arrangement of the table is caused by the need to use special accessories to hold third-party embedded elements of the case. A metal part - a contactor - is used as an embedded element. Due to the specific mortgage they made, as well as the experimental equipment, the authors came to the conclusion that it is economically more expedient to design and manufacture a prototype 3D printer than to modify the existing device. A sample of the FDM printing device was designed, manufactured and tested.

Abstract: The article shows the advantage of electric arc synthesis and subsequent centrifugal spraying of tungsten carbide to obtain a high-quality highly dispersed powder. A tungsten electrode (anode) is fed to the surface of a rotating graphite electrode (cathode) until an electric arc occurs between the electrodes, and the cathode is made in the form of a ring. The angular speed of rotation of the annular graphite electrode is set in accordance with the calculated ratio, which provides fine-dispersed centrifugal atomization of the molten product particles. To prevent intense evaporation of tungsten and the formation of an excessive amount of fine particles, the power of the electric arc for melting the anode is limited to a set value.As a result, the uniformity of the powder increases and the dispersion of the particles of the main fraction decreases.

Abstract: The article proposes a method for obtaining a digital twin of the process of 3D printing by electric arc surfacing using an ensemble of machine learning methods. On the basis of the structural-parametric approach, a set of diagnostic parameters for the signals of current strength, voltage and acoustic emission was determined. Using exploratory analysis, the significance of each diagnostic parameter was assessed. A complex of statistical models has been developed to assess the stability of 3D printing processes using decision trees. Their optimal parameters and efficiency have been determined.

Abstract: The use of friction welding with mixing allows to obtain non-defectal compounds of both alloy AL25 and dispersed particles composite aluminum materials. It was found that in addition to changes in the grain structure of the α-Al solid solution, there are changes in the process of the release of particles of intermetallide phases, which can be traced in the morphology, medium size and chemical composition of particles of intermetallide phases of different natures. The change in the morphology of secondary phase particles is due to the difference in thermo mechanical influence in different areas of the formation of the compound when welding friction with mixing.

Abstract: The production of a precursor of magnesium aluminate spinel (AMS) by thermic synthesis to obtain a material with high-performance properties is reviewed in the work. The temperature synthesis of AMS is determined, the introduction of the additive is described in the range of concentrations of 3, 5, and 7 mol.%. The current processes during the firing of products have been investigated with a view to the further selection of the firing mode of the ceramic samples, which can be obtained.

Abstract: Experimental studies magnetorheological elastomer specimens dynamic properties under the magnetic fields action on the vibrostend are carried out. Amplitude-frequency characteristics have been obtained. The magnetic field effect on the silicone magnetoreactive elastomers deformation properties and damping coefficients experimentally is established.

Abstract: Magnetic properties of the R₂Fe₁₇ compounds are sensitive to the atomic substitutions and interstitial absorption of nitrogen. In our work, both were combined and their effect on the magnetization behavior of Er₂Fe₁₇ compound in magnetic fields up to 58 T was studied. Er₂Fe₁₇N₂, Sm_1.2Er_0.8Fe₁₇N₂ and Sm_1.8Er_0.2Fe₁₇N_2.1 nitrides were prepared. Magnetization measurements were carried out, mainly on powder samples (excluding Er₂Fe₁₇ single crystal). Nanopowders of Sm_1.2Er_0.8Fe₁₇N₂ were obtained by mechanical grinding. The grinding time was varied from 0 to 60 minutes. The strength of the inter-sublattice coupling in samples is estimated by analyzing high-field magnetization data.