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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design and manufacture of engineered titanium-based materials for biomedical applications

Almushref, Fares R. January 2017 (has links)
Metallic materials have gained much attention recently from the areas of medical devices and orthopaedics. Artificial organs, dental implants, prostheses and implants that replace damaged or malfunctioning parts in the body are, or contain, metal components. Our ageing society poses an increased demand to provide devices and implants that can demonstrate better performance than those presented by traditional solutions. Matching the mechanical properties (i.e. stiffness and strength) of the device to those of the host tissue is a major challenge for the design and manufacture of engineered metal materials for biomedical applications. Failure in doing so provokes implant loosening, patient discomfort and repeated surgeries. Therefore, tailoring physical properties and biocompatibility of those materials is the main final aim of this research programme. This PhD study has focused on the tailoring of the mechanical properties of titanium-based materials and titanium-based alloys. Titanium inertness and the selection of biocompatible alloying elements were set as the baseline. Two approaches were employed to decrease stiffness (i.e. Young s modulus): one, by introducing porosity in a titanium matrix and therefore, reduce its Young s modulus, and two, by designing and manufacturing beta-titanium-based alloys with a reduced Young s modulus. Titanium scaffolds were manufactured using powder metallurgy with space holder technique and a sintering process. Different space holder sizes were used in four different categories to study the effect of pore size and porosity on the mechanical properties of the porosity engineered Ti scaffolds. Ti-based alloys were manufactured using manufacturing techniques such as sintering and arc-melting. The effect of different fabrication processes and the addition of beta-stabilising elements were studied and investigated. The obtained results of mechanical properties for pore size and porosity were within the values that match bone properties. This means these materials are suitable for biomedical application and the beta-Ti alloys results show that the mechanical properties can be decreased via tailoring the crystal structures. The characterisation of the Ti-based alloys helps to develop this material for its use in biomedical application.
2

Разработка рекомендаций по внедрению аддитивных технологий в российское металлургическое производство : магистерская диссертация / Development of recommendations on the introduction of additive technologies in the Russian metallurgical industry

Соколов, И. А., Sokolov, I. A. January 2018 (has links)
This qualification work consist of 123 pages, 30 pictures, 13 tables, 61 references and 2 appendixes. Object – Additive manufacturing in metallurgy. Subject – Organizational, technical and economic relations arising in the manufacturing processes of products based on additive technologies. The main purpose is developing of recommendations for involving the additive technologies taken into account business processes’ changes and production activities’ reflections of economic models. Research objectives: 1 Studying the influence of additive technologies on economic development in Russia and abroad. Identifying the main application branches of manufacturing. 2 Determination the current trends in additive technologies’ progress. Characterization the main processes and specifications. 3 Creating strategic elements for implementing the additive technologies, making aspects of business processes and functional economic models. Scientific novelty lies in the forming the upgraded supply chain at the areas of internal and external environment, and working-out universal business model of companies’ activities in the case of involving the additive technologies. Investment projects were calculating for comparison between the SLM and EBM technologies. Indicators of investment attractiveness of these technologies are presented. A method has been developed that allows to assess the ability of companies to introduce additive technologies, which has an advisory nature. / Выпускная квалификационная работа магистранта содержит 123 с, 30 рис., 13 табл., 61 библиографический источник, 2 приложения. Объект исследования – аддитивные технологии в металлургии. Предмет исследования – организационно-технические и экономические отношения, возникающие в процессе изготовления изделий на основе аддитивных технологий. Целью диссертационной работы является разработка рекомендаций по внедрению аддитивных технологий в металлургическое производство с учетом изменений в бизнес-процессах и экономических моделях, отражающих производственную деятельность предприятий. Цель обусловила ряд следующих задач: 1 Изучить влияние аддитивных технологий на экономическое развитие в России и за рубежом, обозначить основные перспективы их применения в различных отраслях экономики. 2 Определить современные тенденции развития аддитивных технологий в металлургии, охарактеризовать основные технологические процессы и их параметры. 3 Разработать элементы стратегии внедрения аддитивных технологий с учетом изменения в бизнес-процессах и экономических моделях функционирования организаций. Дано описание процессов аддитивного производства. За основу были взяты наиболее изученные технологии – процессы SLM и EBM, применительно к производству изделий из сплава Ti-6Al-4V и его отечественного аналога, сплава ВТ6. Приведены аспекты влияния аддитивных технологий на изменения в цепочках поставок и бизнес-моделях функционирования организации. Произведены расчеты инвестиционных проектов представленных технологий аддитивного производства. Представлен механизм оценки возможности организации к внедрению аддитивных технологий, имеющий рекомендательный характер.

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