The dissertation will be defended at the public meeting of the Dissertation Defence Council of the Scientific Field of Materials Engineering in the SRA-I Meeting Hall of Vilnius Gediminas Technical University at 2 p.m. on 10 June 2024.
The dissertation examines 18% Ni maraging steel 1.2709 (DIN) widely used in producing products and parts across various technical fields by additive manufacturing methods, e.g., selective laser melting (SLM). To enhance the surface hardness and improve the wear resistance of this steel, a laser alloy-ing method was proposed, which could become an effective, less energy-consuming, time-saving and environmentally safer alternative to the currently applied thermochemical nitriding method. The work consists of an introduction, three chapters, general conclusions, lists of used literature and the author’s publications on the dissertation topic. The introductory chapter discusses the research problem, the relevance of the work, describes the object of the research, formulates the purpose and tasks of the work, describes the research methods, the scientific novelty of the work, the practical significance of the work results, and presents the defended statements. The first chapter presents a literature review and analysis on the topics of additive manufacturing, maraging steels and metal surface modification methods. The chapter closes with conclusions and specifies dissertation tasks. The second chapter describes the materials used for the research, the laser boronising methodology, the boronised surface characterisation methods and the equipment used. The third chapter presents the research results and their analysis. The process of laser boronising is examined, applying it before and after heat treatment of steel samples, its effect on the structure and properties of modified surfaces and the properties of the base metal in the heat-affected zone. Five articles were published on the dissertation topic, two of them were published in publications of the Clarivate Analytics Web of Science database and research results were presented at 10 national and international scientific conferences.
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