Structure and Deformation Behavior of Ti-SiC Composites Made by Mechanical Alloying and Spark Plasma Sintering

Combining high energy ball milling and spark plasma sintering is one of the most promising technologies in materials science. The mechanical alloying process enables the production of nanostructured composite powders that can be successfully spark plasma sintered in a very short time, while preserving the nanostructure and enhancing the mechanical properties of the composite. Composites with MAX phases are among the most promising materials. In this study, Ti/SiC composite powder was produced by high energy ball milling and then consolidated by spark plasma sintering. During both processes, Ti3SiC2, TiC and Ti5Si3 phases were formed. Scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction study showed that the phase composition of the spark plasma sintered composites consists mainly of Ti3SiC2 and a mixture of TiC and Ti5Si3 phases which have a different indentation size effect. The influence of the sintering temperature on the Ti-SiC composite structure and properties is defined. The effect of the Ti3SiC2 MAX phase grain growth was found at a sintering temperature of 1400–1450 °C. The indentation size effect at the nanoscale for Ti3SiC2, TiC+Ti5Si3 and SiC-Ti phases is analyzed on the basis of the strain gradient plasticity theory and the equation constants were defined

Powder metallurgy in Łukasiewicz Research Network – Metal Forming Institute

W artykule przedstawiono metody metalurgii proszków wykorzystywane do wykonywania wyrobów z proszków metalicznych i ceramicznych w Sieci Badawczej Łukasiewicz – Instytucie Obróbki Plastycznej. Do wytwarzania zaawansowanych materiałów metalicznych, ceramicznych oraz kompozytowych zastosowano nowoczesną metodę spiekania iskrowo-plazmowego z wykorzystaniem urządzenia SPS HP D 25-3. Urządzenie to pozwala na realizację procesów spiekania w temperaturze do 2200°C z jednoczesnym prasowaniem z siłą do 250 kN w próżni, atmosferze azotu, argonu lub wodoru. Z kolei do wykonywania wyrobów z proszków na bazie żelaza stosowana jest konwencjonalna metoda prasowania jednoosiowego na zimno i następującego po nim spiekania swobodnego w atmosferze azotowo-wodorowej zdysocjowanego amoniaku z wykorzystaniem gniazda badawczo-doświadczalnego GSMP-75 wyposażonego w piec wgłębny retortowy PSF-12/75. Maksymalna temperatura spiekania wynosi 1200°C. Ponadto omówiono przykładowe prace naukowo-badawcze zrealizowane w ramach zarówno projektów międzynarodowych finansowanych z 7 PR UE oraz Horyzontu 2020, jak i projektów krajowych realizowanych we współpracy z przemysłem. Zaprezentowano wybrane wyniki badań dotyczące kompozytowych sektorów tnących stosowanych w piłach do cięcia kamieni, kompozytowych elektrod nasadkowych stosowanych w zrobotyzowanych stanowiskach zgrzewania punktowego oraz płytek skrawających wykonanych z węglików spiekanych stosowanych w obróbce mechanicznej metali. Poza tym wskazano gałęzie przemysłu, na potrzeby których ŁUKASIEWICZ – INOP wykonuje prace naukowo-badawcze oraz realizuje wdrożenia. Zaprezentowano także ofertę współpracy dla przemysłu.The article presents the powder metallurgy methods used to make products from metallic and ceramic powders in the Łukasiewicz Research Network – Metal Forming Institute. To produce advanced metallic, ceramic and composite materials, the method of spark plasma sintering employing an SPS HP D 25-3 was used. This device allows sintering processes to be performed at temperatures up to 2200°C with simultaneous compaction with a force of up to 250 kN in vacuum, and in a nitrogen, argon or hydrogen atmosphere. On the other hand, to make products from iron-based powders, the conventional method of cold uniaxial pressing and subsequent free sintering in a nitrogen-hydrogen atmosphere of dissociated ammonia employing a GSMP-75 research and testing socket equipped with a PSF-12/75 retort furnace is used. The maximum sintering temperature is 1200°C. In addition, examples of scientific and research work carried out as part of international projects financed from EU FP7 and Horizon 2020, as well as national projects executed in cooperation with industry are discussed. Selected research results concerning composite cutting sectors used in saws for cutting stones, composite cap electrodes used in robotic spot welding stations and cutting inserts made of cemented carbides used in metal machining were presented. In addition, the branches of industry were identified for which the Łukasiewicz Research Network – Metal Forming Institute performs scientific and research works and executes implementations. A cooperation offer for industry was also presented

Tribological and biotribological research in the Laboratory of Surface Engineering and Tribology of Łukasiewicz Research Network – Metal Forming Institute

W niniejszej pracy przedstawiono wyniki badań, które są efektem realizowanych w Sieci Badawczej Łukasiewicz – Instytucie Obróbki Plastycznej zarówno projektów krajowych, jak i międzynarodowych, dotyczących tematyki tribologicznej oraz biotribologicznej. Przedstawiono wyniki badań, których efektem jest opracowanie nowej generacji narzędzi kuźniczych (zaprojektowanie narzędzi do kucia na zimno z odpowiednio przygotowaną powierzchnią roboczą i opracowanie nowych wielowarstwowych, nanostrukturalnych powłok gradientowych) oraz rozwiązanie problemu wczesnego zużywania się części pracujących w trudnych warunkach eksploatacyjnych. Dla elementów trących pracujących w wysokiej temperaturze opracowano rozwiązanie, które znalazło praktyczne zastosowanie w przemyśle w zakresie poprawy technologii smarowania. Opracowanie technologii wprowadzenia cząstek smarów stałych na powierzchnie współpracujących tribologicznie części pracujących w podwyższonych temperaturach stało się niezwykle istotne dla wielu gałęzi przemysłu, które spotykają się na co dzień z problemami wczesnego zużywania elementów współpracujących. W drugiej części pracy skupiono się na problemach biotribologicznych, gdzie głównym wyzwaniem jest wydłużenie trwałości endoprotez stawu biodrowego. W związku z tym prowadzono prace związane z dokładnym poznaniem procesu zużywania się endoprotez. Bardzo ważną kwestię stanowi również badanie właściwości tribologicznych nowych materiałów przeznaczonych na elementy endoprotez. Badania prowadzono na specjalnie do tego celu zaprojektowanym i zbudowanym symulatorze stawu biodrowego, który spełnia wymogi normy ISO.This paper presents the results of research, which are the effect of national and international projects carried out at the Łukasiewicz Research Network – Metal Forming Institute, concerning both tribological and biotribological topics. The research results, the effect of which is the development of a new generation of forging tools (the design of cold forging tools with a properly prepared work surface and the development of new multilayered, nanostructured gradient coatings) and the solution to the problem of early wear of the parts working in difficult conditions are presented. For friction elements operating at high temperature, a solution has been developed that has found practical applications in the industry in the field of improving lubrication technology. The development of the technology of introducing solid lubricant particles onto the surfaces of tribologically cooperating parts operating at elevated temperatures has become extremely important for many industries that daily face problems with the early wear of cooperating elements. The second part of the work focuses on biotribological problems and the main challenge is to extend the durability of hip joint endoprostheses. In connection with this, work was carried out to thoroughly understand the process of endoprosthesis wear. Examination of the tribological properties of new materials intended for elements of endoprostheses is also a very important issue. The research was conducted on a specially designed and built hip joint simulator, which meets the requirements of the ISO standard

Cold Spray Powders and Equipment

Chapter 3A particle shock consolidation encountered in the coldspray (CS) process is defined by a highvelocity impact of powder particles onto the substrate. The particle impact results in the generation of high stresses and strains both in the particles and the substrate. As shown in the basic monographs (Champagne, 2007; Papyrin et al., 2007), the powder material to be sprayed must feature sufficient ductility to ensure particle strains and cold welding without its failure. In some cases (at very high particle velocities) Ti alloy particle melting occurs (Vlcek et al., 2002). However, impact of other metallic powder materials is characterized by high stresses and particle shear strains. Because a lot of information is available on various powders and powder mixtures developed and applied for cold spraying (Jeandin et al., 2014; Moridi et al., 2014, and others), the goal of this chapter is to describe and discuss the concept of CS material selection, basic criteria for evaluation of its suitability for cold spraying, and particle behavior during the deposition process (acceleration and formation of interfaces)Book chapterPaolo Matteazzi , Alberto Colella , Volf Leshchynsky , Kazuhiko Sakaki et al. "Chapter 3. Cold Spray Powders and Equipment". Cold Gas Dynamic Spray. Roman Gr. Maev, Volf Leshchynsky, eds. CRC Press, 2016, p.95-118.boo

Microstructure and Mechanical Properties of Spark Plasma Sintered and Severely Deformed AA7075 Alloy

In this paper, the microstructure and mechanical properties of AA7075 with a coarse-fine-grained laminated microstructure produced by spark plasma sintering (SPS) and the cyclic extrusion severe deformation (KOBO) technique were investigated. It was found that an inhomogeneous grain microstructure was formed from coarse and fine grains by the SPS process and then was transformed into a coarse-fine-grained laminated microstructure by means of KOBO extrusion at room temperature. The grain refinement during KOBO extrusion resulted in a fine grained laminated microstructure created due to the formation of low-angle grain boundaries (LAGBs), followed by dynamic recrystallization, leading to high-angle grain boundaries (HAGBs). The EBSD analysis results reveal the formation of a deformed and partially recrystallized ultrafine grain microstructure owing to the generation and development of shear bands during KOBO extrusion. The ultimate tensile strength (UTS) of the AA7075 alloy rose after SPS-KOBO severe deformation up to 422 MPa, with high strains of about 33%. The obtained results clearly show that the SPS-KOBO extrusion technique allows a bimodal laminated fine gradient grain microstructure to be obtained due to deformation and dynamic recrystallization, which result in both high strength and good ductility. The new heterogeneous AA7075 alloys obtained by the SPS-KOBO combined techniques demonstrate that microstructural heterogeneities can assist in overcoming the strength–ductility trade-off

Microstructure and Properties of Hydroxyapatite Coatings Made by Aerosol Cold Spraying–Sintering Technology

Hydroxyapatite is a widely used material used for the bioactivation of an implant’s surface. A promising hydroxyapatite coating approach is the kinetic deposition of powder particles. The possibility of solid-state deposition improvement through the merging of Aerosol Deposition and Low Pressure Cold Spraying techniques is a promising prospect for improving the deposition efficiency and the quality of coatings. The objective of the paper is to study the possibilities of hydroxyapatite coating structure modification through changes in the coating process and post-heat treatment. The novel Aerosol Cold Spraying system joining Low Pressure Cold Spraying and Aerosol Deposition was used for the deposition of coatings. The coating’s post-processing was conducted using two techniques: Spark Plasma Sintering and Pressureless Sintering. The coating’s structure was examined using scanning, transmission, and light microscopy, and X-ray diffraction. Substrate–coating bond strength was assessed using a tensile test. Homogenous buildup using Aerosol Cold Spraying of hydroxyapatite was achieved. Various pores and microcracks were visible in the sprayed coatings. The deposition process and the thermal post-processing did not lead to significant degradation of the hydroxyapatite phase. As a result of the Spark Plasma Sintering and Pressureless Sintering at 800 °C, an increase in tensile adhesion bond strength and crystal size was obtained