The dissertation deals with the design of strong magnetic field systems, structural features and properties of modern Cu-Nb conductors, production specifics and applications of microcomposite conductors, their connection problems and applicable connection technologies, structure of welded joints of Cu-Nb microcomposite conductor welded by four special methods, strength and electrical properties. The aim of dissertation – to determine the effect of Cu-Nb conductor welding methods and their parameters on the microstructure of welded joints, mechanical and electrical properties. The research aims to solve one of the important problems in strong magnetic field systems by developing conductor joining technology and by creating non-destructive electro-contact joints of microcomposite conductors that meet the requirements of electric contacts.
The proposed solutions will help to solve the problems of production and reliability of existing and developed pulsed magnetic systems, industrial induction systems, next-generation levitation vehicles and modern Cu-Nb conductors of high-voltage power lines, will save production time and economic resources due to reduced number of technological and maintenance operations, compared to traditional methods of producing destructive electrocontact joints. The introductory chapter discusses the research problem, the relevance of the work, describes the object of research, formulates the aim and objectives of the work, describes the research methodology, scientific novelty of the work, the practical significance of the results, defended statements. At the end of the introduction, the author's publications and conference papers on the topic of the dissertation and the structure of the dissertation are presented. The first chapter reviews the existing structures of pulsed magnets and their components, examines the production methods of Cu-Nb microcomposite conductors, the structure and properties of these conductors, their technical possibilities of welding, analyzes the specifics of welding processes. At the end of the chapter, the conclusions of the literature review are formulated and the tasks of the dissertation are specified. The second chapter describes the materials used in the work and technological and research equipment, the methods of structure and properties research used in the work, experimental methodology, welding technology and material selection methodology, the methodology of calculating the main parameters. The third chapter presents the results of microstructure, phase composition studies, mechanical properties, electrical properties studies and calculation of welding parameters and analysis of these data. 7 articles on the topic of the dissertation have been published, and the research results have been presented at 10 scientific conferences in Lithuania and abroad.
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