OUR ACTIVITIES IN THE REGIONAL MATERIALS SCIENCE AND TECHNOLOGY CENTRE

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1 OUR ACTIVITIES IN THE REGIONAL MATERIALS SCIENCE AND TECHNOLOGY CENTRE Jaromír DRÁPALA, Miroslav KURSA, Miroslav GREGER, Ivo SZURMAN, Silvie BROŽOVÁ, Jitka MALCHARCZIKOVÁ, Daniel PETLÁK, Václav NÉTEK, Zdeněk NOGA, Michal MADAJ, Martin POHLUDKA Vysoká škola báňská Technical University of Ostrava, Faculty of Metallurgy and Materials Science, Av. 17. listopadu 15, Ostrava Poruba, Czech Republic, Abstract The objective of the project Regional Materials Science and Technology Centre (RMTVC) is to build laboratories and teams that will develop, prepare, investigate and optimise advanced materials and metallurgical technologies. The centre is focused on the preparation of highly pure materials, special alloys, bio-medical materials, development of materials for high temperature applications, power engineering, etc. The following research program was formulated for Working Group VP1: Development and optimisation of new technologies of highly pure materials, special metallic alloys and intermetallic compounds (IMC) with the defined structure and physical properties for applications in electronics, medicine, mechanical engineering and chemical industry. The Department of preparation of materials consists of the Laboratory of pure metals" and the Laboratory of special materials. The focus of the research and development activities of the Department of preparation of materials is concentrated on the following key issues: Investigation of processes of the metallic materials refining, preparation of single crystals and defined materials, determination of the origin and distribution of admixtures in crystals and investigation of physical-chemical properties of highly pure substances and regularities of changes of their properties in dependence on their chemical composition, concentration of admixtures, crystalline defects and structural parameters. Key words: Pure metals; crystallization; alloys; intermetallic compounds; metallurgy; single crystals. 1. INTRODUCTION The project Regional Materials Science and Technology Centre (RMTVC) concerns predominantly the Faculty of Metallurgy and Materials Engineering (FMME). The research and development orientation of the FMME is in conformity with the University long-term concept focused on the following disciplines: metallurgy of metals (ferrous and non-ferrous), chemical metallurgy, materials engineering, forming and heat treatment. A specific objective of the RMTVC is to build laboratories and teams that will develop, prepare, investigate and optimise advanced materials and technologies of their preparation for the application sphere. The centre is focused on the preparation of highly pure materials, special alloys, bio-medical materials, development of materials for high temperature applications, and power engineering, preparation of materials by advanced powder metallurgy technologies (magnetic materials, friction materials, composite materials, etc.), preparation of nano-crystalline materials based on non-ferrous metals, their alloys and steels prepared by severe plastic deformation, research of processes running in the liquid phase of reactors that affect the utility properties of materials, physical and mathematical modelling of the materials forming processes, including forging, and application of the obtained findings in research and development of technology of forming the components for nuclear power engineering equipment. The complexity of technological solutions of materialtechnological issues is further deepened by investigation of degradation processes of materials caused by corrosion, high temperatures, stress states and embrittlement due to the hydrogen effects, and their impact

2 on the degradation mechanism and safety at operational applications. From the material point of view this concerns new advanced materials, but also traditional structural materials, such as steel. 2. MAIN ACTIVITIES OF THE RMTVC The structure of the RMTVC centre was also subordinated to envisaged outputs into the industrial sphere with a strong application potential. Organisational structure of the centre is divided into five departments: 1. Department of preparation of materials (laboratory of pure metals and laboratory of technology for preparation of special materials). 2. Department of powder technologies (laboratory of magnetic and ceramic materials, laboratory of friction composites). 3. Department of forming processes (laboratory processes of severe plastic deformation, laboratory materials with ultra fine-grained structure prepared by forming, laboratory of modelling and optimisation of the forming technologies). 4. Department of evaluation of materials properties (laboratory of structural analysis, laboratory of mechanical properties, laboratory of chemical analyses, laboratory of surface analysis and corrosion, laboratory of physical properties). 5. Department of experimental verification of technologies and applications (laboratory for experimental verification of technologies for the production of new materials and laboratory of modelling of processes in the liquid and solid phases). On the basis of the existing results of the research and development and in collaboration with potential customers in the application sphere the following research programs were formulated during the preparation of the RMTVC project: 1. Development and optimisation of new technologies of highly pure materials, special metallic alloys and intermetallic compounds with defined structures and physical properties for applications in electronics, medicine, mechanical engineering and chemical industry. 2. Development and optimisation of processes of powder technologies for production of selected types of materials and products 3. Control of specific properties of intensively rolled and thermo-mechanically processed materials using their structural potential. 4. Research of metallic materials with ultra fine-grained structure (nano-structure), and development of processes for their preparation 5. New sources of strength and toughness of materials for demanding technological applications. 6. Experimental verification of new technological procedures for metallic materials with high quality parameters. The RMTVC centre links its activities to the R&D activities of the applicant and its partner the company Material & Metallurgical Research Ltd. and the long-term mutual cooperation, the complexity of which in the field of metallurgy and processing of metallic materials represents a unique working site in the context of the Czech Republic and contributes significantly to the development of its material base. 3. ACTIVITIES AT THE DEPARTMENT OF PREPARATION OF MATERIALS The Department of preparation of materials consists of the Laboratory of pure metals" and the Laboratory of special materials. The focus of research and development activities of the Laboratory of pure metals is concentrated on the following key issues: Investigation of processes of refining metallic materials, preparation of single crystals and defined materials, determination of the origin and distribution of admixtures in the crystal and investigation of the physical-chemical properties of highly pure substances and regularities

3 of changes of their properties in dependence on their chemical composition, concentration of admixtures, crystalline defects and structural parameters. The project aims to build a research infrastructure of the laboratories of the Department of preparation of materials, as well as scientific-research teams that will develop, prepare and optimise properties of advanced materials and technologies of their preparation for the application sphere. The current trend is focused on the preparation of composite materials with metallic matrix, super-alloys, titanium alloys, intermetallic compounds based on aluminides and borides, aluminium alloys, magnesium alloys and magnetic materials. Problems related to the preparation of these materials involve not only the removal of harmful impurities, but also the maximum approach to the stoichiometric composition. In this context, a very important role is played by the knowledge of the phase equilibrium of binary or polycomponent diagrams in the temperature-concentration zone of existence of a chemical compound and the specificity of interactions between individual components at the crystallization as the final stage at the production of volume of crystals. The department work is focused on the achievement of peak parameters in terms of purity of materials and controlled structure. It includes the range of materials from low-meting alloys with the melting point of 300 C (new types of lead-free solders) up to the melting temperature of 2200 C (special alloys and intermetallic compounds). 3.1 Project Start-up Basic guidelines of the project Start-up : - Building of a complex of modern metallurgical equipment for preparation of highly pure metallic crystalline materials, special alloys and advanced materials - Development and optimisation of technology of zone melting (Floating zone method) for preparation of single crystals of high-melting metals and their low-alloyed alloys - Development and optimisation of technology of directional crystallisation of nickel and titanium alloys. - Development, preparation and optimisation of alloys and intermetallic compounds Ni-Al, Ti-Al and Ti-Ni. - Development and preparation of unconventional alloys by the plasma melting process in the vertical mould. - Preparation of metallic materials with the defined physical and structural parameters and investigation of their characteristics from the viewpoint of the application output. Technological processing of these materials by the forming processes (in collaboration with the department 31). - Preparation of materials with new utility properties and increased service life in extreme conditions. - Optimisation of crystallisation processes in order to achieve the structural and chemical homogeneity of crystalline high-temperature and magnetic materials. - Development of new types of lead-free solders (HISOLD) for the electronics, heat exchangers, automotive industry, etc. - Elaboration of new technologies and enhancement of the existing ones for preparation of highly pure crystals in order to obtain numerous metals with the purity of 5N. 3.2 Objectives of the applied research for the period The focus of the R&D activities of the Laboratory of pure metals and special alloys is focused mainly on: 1. Investigation of metal refining processes by metallurgical ways in order to achieve the maximum possible purity and defined chemical structures, including micro- and macro-homogeneity. 2. Preparation of metallic single crystals of pure metals and low-alloyed alloys, selection of melting units, optimisation of technological parameters, preparation of oriented nuclei, investigation of basic characteristics of single crystals. 3. Investigation of physical-chemical properties of highly pure substances and regularities of changes of their properties in dependence on their chemical composition, concentration of admixtures, crystalline defects and structural parameters. 4. Research of new types of bio-compatible materials for medical applications.

4 5. Research of new types of inter-metallic compounds for power engineering, aerospace and mechanical engineering industry. 6. Research of the interaction of elements in functionally gradient materials at high temperatures. 7. Research of the interaction of hydrogen in advanced types of materials. Cooperative workplaces in the framework of the RMTVC are especially: department of metals forming, powder metallurgy, diagnostics of materials properties and others. 4. INSTRUMENTATION OF THE DEPARTMENT OF PREPARATION OF MATERIALS R&D activities of the Laboratory of pure metals" and the Laboratory of special materials are focused on the building of experimental furnaces for plasma metallurgy, vacuum metallurgy, processes of normal freezing of melts, quick solidification of melts. The chosen instruments cover a wide spectrum of technologies of the preparation of progressive materials with directed structure and properties [1]. It includes a large area of materials (metals, alloys and intermetallic compounds with the melting point from 200 C (solders) to 3420 C (tungsten). Laboratory furnaces and other equipments: (Figures 1 to 5) High-temperature vacuum induction furnace with cold crucible Laboratory equipment for preparation of single crystals by the Czochralski method Electron-beam furnace for refining of metals and preparation of single crystals (floating zone method) Equipment for directional solidification of metals and alloys Plasma furnace with a vertical mould Equipment for induction centrifugal casting "SuperVac" High-temperature vacuum furnace for annealing of samples (2200 C] Equipment for division and processing of samples Hydrogen analyzer 5. CONCLUSION The research program was formulated for the Department of preparation of materials : Development and optimisation of new technologies of highly pure materials, special metallic alloys and intermetallic compounds with the defined structure and physical properties for applications in electronics, medicine, mechanical engineering and chemical industry. ACKNOWLEDGEMENTS This work is supported by the Ministry of Education, Youth and Sports, Czech Republic, the project of OP VaVPI Regional Materials Science and Technology Centre (RMTVC) No. CZ.1.05/2.1.00/

5 Anode Metal Ions Moving Path Electron Filament (Cathode) Highvoltage power supply V Vacuum system Focussing Plate Electron Moving Path Sample Molybdenum single crystal Ø 8 mm after deformation at the room temperature Fig. 1 Furnace for the electron beam zone melting in high vacuum, firm Delong Instruments (floating zone method) 1 focusing system, 2 W cathode, 3 electron beam, 4 melt (zone) of metal, 5 crystal, 6, 8 holders, 7 vacuum chamber

6 Fig. 2 Induction centrifugal casting unit firm Linn, Germany (titanium, titanium alloys, superalloys (max. casting weight 2 kg Ti) Plasmatron Gas Cathode Water Smelted Metal Water Plasma Jet Melt Single Crystal Seed Water-Cooled Cu-rod Fig. 3 Equipment for plasma metallurgy with the vertical crystallizer

7 seed holder, 2 - seed, 4 - "Dash neck", 9 - inductive or electron beam heating, 5, 6 - crystal, 7 - crucible, 8 melt 10 auto-crucible Fig. 4 Czochralski method for production of single crystals of refractory metals and intermetallic compounds Fig. 5 Hydrogen analyzer, firm Leco (max wt. ppm H 2 )