Search Results (3)

Currently, additive manufacturing technologies for materials and products are being implemented and improved. This is due to the possibility of creating workpieces with complex geometric shapes and specified functional gradient properties. The materials with the most complex functional properties demanded by the military–energy industry include bimetals of the “low-alloyed carbon steel—stainless chromium-nickel steel” type. One of the promising ways to obtain bimetallic products is the WAAM (Wire Arc Additive Manufacturing) technology. Despite the large scientific groundwork, the composition, structure, and properties of bimetallic composites produced by WAAM have not been sufficiently studied. The aim of the current work is to study the effect of WAAM parameters and the subsequent heat treatment on the composition, structure, and physical and mechanical properties of the bimetallic composite “ER70S-6-R309LSI”. Spectral, metallographic, and X-ray diffraction studies were carried out, as were mechanical tests of the samples obtained under various WAAM modes. In order to improve the composites’ properties, various types of heat treatments were applied. It is shown that the WAAM modes, the building strategy, and heat treatment determine the structure of layers and transition zones, as well as the mechanical characteristics of the composite. The structure of ER70S-6 in the composite is represented by the ferrite and the ferrite–cementite mixture (pearlite), and ER309LSI is represented by different ratios of austenite, δ-ferrite, carbide, and intermetallic phases. From the point of view of the mechanical properties, the most promising mode of surfacing is “Double Pulse”, followed by heat treatment by way of austenitization and normalization annealing. In this case, there is a decrease in the content of the δ-ferrite, a leveling of microhardness values, and a 40% increase in the tensile strength of the composite. Full article

The digital twin has recently become a popular topic in research related to manufacturing, such as Industry 4.0, the industrial internet of things, and cyber-physical systems. In addition, digital twins are the focus of several research areas: construction, urban management, digital transformation of the economy, medicine, virtual reality, software testing, and others. The concept is not yet fully defined, its scope seems unlimited, and the topic is relatively new; all this can present a barrier to research. The main goal of this paper is to develop a proper methodology for visualizing the digital-twin science landscape using modern bibliometric tools, text-mining and topic-modeling, based on machine learning models—Latent Dirichlet Allocation (LDA) and BERTopic (Bidirectional Encoder Representations from Transformers). The scope of the study includes 8693 publications on the topic selected from the Scopus database, published between January 1993 and September 2022. Keyword co-occurrence analysis and topic-modeling indicate that studies on digital twins are still in the early stage of development. At the same time, the core of the topic is growing, and some topic clusters are emerging. More than 100 topics can be identified; the most popular and fastest-growing topic is ‘digital twins of industrial robots, production lines and objects.’ Further efforts are needed to verify the proposed methodology, which can be achieved by analyzing other research fields. Full article

The study of hadronic resonance production is an essential part of the physical programs of many heavy-ion experiments. Detailed measurement of the resonance properties is also foreseen in the future Multi-Purpose Detector (MPD) experiment at the NICA collider. In this report, we focus on the experimental challenges for the reconstruction of resonances in heavy-ion experiments and examine the MPD capabilities for the reconstruction of ρ(770)⁰, K*(892)^0,±, φ(1020), Λ(1520), Σ(1385)^± and Ξ(1530)⁰. Full article