Layered composite materials based on niobium and cermet were produced via self-propagating high-temperature synthesis of pre-structured samples using metal foils (Ti, Nb, Ta, Ni) and reaction tapes (Ti + 1.7B) and (5Ti + 3Si). Reaction tapes for synthesis were produced by rolling process of powder mixtures. The microstructure, elemental and phase compositions of the synthesized multilayer composite materials were studied by scanning electron microscopy and X-ray phase analysis. Particular attention was paid to the formation of intermediate layers and surface modification occurring during combustion. The strength characteristics of synthesized materials were determined according to the three-point loading scheme at temperatures of 1100°C. The analysis of obtained materials showed that joining in the combustion mode of metal foils and reaction tapes is provided due to reaction diffusion, mutual impregnation and chemical reactions occurring in the reaction tapes and on the surface of metal foils. The formation of thin intermediate layers in the form of cermet and eutectic solutions provides the synthesized multilayer materials with good strength properties up to 87 MPa at 1100°C. These results are of interest for the development of structural materials operating under extreme conditions.

This paper describes the compounds of refractory metal foils (Ti, Hf, Ta, and Ni) with ceramic layers formed as a result of combustion of reaction tapes rolled from Ti + 0.65C, Ti + 1.7B, and 5Ti + 3Si powder mixtures. Scanning electron microscopy and X-ray diffraction analysis are applied to study the microstructure, elemental composition, and phase composition of multilayer composites obtained by self-propagating high-temperature synthesis. The effect of synthesis conditions (initial temperature and applied pressure) and the initial structure of the samples on various parameters (combustion wave front propagation velocity, microstructure, phase composition, and strength properties) of the resulting layered materials is revealed. It is shown that compounds of metal foils and reaction tapes rolled from powder mixtures during combustion are ensured due to reaction diffusion, mutual impregnation, and chemical reactions occurring in the reaction tapes and on the surface of metal foils. The strength properties of the resulting materials (up to 275 MPa at 25°C and up to 72 MPa at 1100°C) are determined using a three-point loading scheme. The results of this study can contribute to the development of structural materials operating under extreme conditions.

Layered composite materials based on niobium and cermet are produced via the self-propagating high-temperature synthesis of preliminarily structured samples using metal foils (Ti, Nb, Ta, Ni) and reaction tapes (Ti + 1.7B) and (5Ti + 3Si). The reaction tapes for synthesis are produced by rolling powder mixtures. The microstructure, and elemental and phase compositions of the synthesized multilayer composite materials are studied by scanning electron microscopy and X-ray phase analysis. Particular attention is paid to the formation of intermediate layers and surface modification occurring during combustion. The strength characteristics of the synthesized materials are determined according to the three-point loading scheme at temperatures of 1100°C. Analysis of the obtained materials shows that joining in the combustion mode of metal foils and reaction tapes is provided due to reaction diffusion, mutual impregnation, and chemical reactions occurring in the reaction tapes and on the surface of the metal foils. The formation of thin intermediate layers in the form of cermet and eutectic solutions provides the synthesized multilayer materials with good strength properties up to 87 MPa at 1100°C. These results are of interest for the development of structural materials operating under extreme conditions.

Ti/Ta/Hf/Ni/ceramic layered composite materials are produced via the self-propagating high-temperature synthesis (SHS) of prestructured samples using metal foils (Ti, Hf, Ta, Ni) and reaction tapes (Ti + 0.65C), (Ti + 1.7B) and (5Ti + 3Si). The reaction tapes are prepared by cold rolling from powder mixtures. The microstructure, and elemental and phase compositions of the synthesized multilayer composite materials are characterized by scanning-electron microscopy (SEM) and X-ray phase analysis. The formation of intermediate layers and modification of the surface of the metal foils is given individual attention. Their flexural strength is determined according to the scheme of three-point loading at temperatures of 25 and 1100°С. Microstructure analysis of the produced materials shows that the joining of the metal foils and reaction tapes in the combustion mode is facilitated due to reaction diffusion, mutual impregnation, and chemical reactions occurring in the reaction tapes and on the surface of metal foils. The formation of thin intermediate layers in the form of cermets and eutectic solutions provides the synthesized multilayer materials with good strength properties (up to 275 MPa at 25°С, up to 72 MPa at 1100°С). These results are of interest for the development of construction materials operating under extreme conditions.

Combustion during self-propagating high-temperature synthesis of Ti + 1.7B reaction tapes obtained by rolling from a powder mixture is experimentally investigated. Dependences between the combustion wave propagation velocity in the reaction tapes and the applied pressure are revealed. It is shown that the burning rate of the tapes weakly depends on the compression pressure within 0.001–4 MPa. At a compression pressure above 0.5 MPa, unreacted regions appear during the combustion of the tapes. The limiting pressure at which the combustion stops is determined as 12 MPa.

Слоистые композиционные материалы Ti/Hf/Ta/Ni/керамика получены из предварительно структурированных образцов с использованием металлических фольг (Ti, Hf, Ta, Ni) и реакционных лент (Ti + 0.65C), (Ti + 1.7B) и (5Ti + 3Si), полученных прокаткой из порошковых смесей, которые при горении формировали керамические слои. Микроструктура, элементный и химический состав многослойных композитов изучены методами СЭМ и РСА. Прочностные характеристики синтезированных материалов определяли по схеме трехточечного нагружения при температурах 25°С и 1100°С. В результате высокотемпературных реакций, протекающих в реакционных лентах, удалось соединить фольги титана, гафния и тантала. Анализ микроструктуры синтезированных образцов показал, что соединение в режиме горения между металлическими фольгами и реакционными лентами, прокатанными из порошковых смесей, обеспечивается за счет реакционной диффузии, взаимной пропитки и химических реакций, протекающих в реакционных лентах и на поверхности металлических фольг. Введение в состав структурированных образцов фольг тантала повышает прочность композиционных материалов (до 275 МПа при 25 °С, до 72 МПа при 1100 °С).

Ta/Ti/Ni/ceramic multilayered composites were successfully prepared by combustion synthesis. Laminated composites Ti–Ta–(Ti + 0.65C)–Ni–(Ti + 1.7B)–(Ti + 1.7B)–Ta–Ni-Ti and 3(Ti + 1.7B)–Ta–(5Ti + 3Si)–Ta–(Ti + 1.7B)–Ta–(5Ti + 3Si)–Ta–3(Ti + 1.7B) were combustion synthesized in an Ar atmosphere using (1) metallic foils (Ti, Ta, Ni) and (2) reactive tapes (Ti + 0.65C), (Ti + 1.7B), and (5Ti + 3Si), which, upon combustion, yielded ceramic layers as starting materials. The microstructure, crystal structure, and chemical composition of multilayered composites were characterized by SEM, EDX, and XRD. Their flexural strength was measured at 1100 °C. Upon combustion, Ta foils turned strongly joined with Ti ones due to the development of high temperature in the reactive layers yielding TiCx and TiBy. The formation of a liquid phase between metallic foils and reactive tapes and mutual interdiffusion between melted components during combustion favored strong joining between refractory metallic foils. Good joining between metals and ceramics is reached due to the formation of thin interfacial layers in the form of cermets and eutectic solutions.

Multilayer Ti–Ta–Ni–TiC–TiB composite (cermet) was obtained by combustion-aided joining in multilayer sandwiches formed by Ti–C and Ti–B reactive layers and metal foils (Ti, Ta, Ni) and characterized by thermographic analysis and rapid video filming. Thin plates of resultant composite (32 × 14 × 1.5 mm) were formed within 0.2 s after ignition (burning velocity 195 mm/s). Ta foils were found strongly joined with Ti ones due to development of high combustion temperatures in the reactive layers yielding TiC and TiB ceramics. The presence of ceramics afforded for reducing material density, on retention of its heat/corrosion resistance. Our results open up new horizons for SHS-assisted fabrication of new refractory materials with required structure/properties.

According to recent studies, the use of nanostructured metal surfaces, especially titanium and titanium alloy surfaces, promotes the growth of bone tissue. In view of these results, in this study, we explored the possibility of generating a specified surface roughness for samples of titanium materials (titanium Grade 4 and Ti6Al7Nb titanium alloy) for bone implants by the gas cluster ion beam (GCIB) treatment technique. The results of GCIB treatment under various conditions for surface modification were evaluated by atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The toxicity of the titanium and titanium alloy materials was evaluated in experiments on the viability and the growth rate of substrate-dependent bone tissue progenitor cells on the surface of the materials. Good prospects for the use gas cluster ion beam technique for the generation of a specified surface roughness of materials based on titanium Grade 4 and Ti6Al7Nb titanium alloy for bone implants were demonstrated.

The possibility of joining ceramic materials with a Ta substrate was explored in the conditions of self-propagating high-temperature synthesis (SHS). The sample used in experiments consisted of Ta foils, Ti + 0,65C pellet, 5Ti + 3Si pellet, and a Ti + 2B igniting tape laid between them. The sample was installed onto a BN base and covered by a chamotte brick (SiO2+ Al2O3) plate with a weight of 3,36 kg placed on top in order to reduce heat sink. Experiments were performed in a closed reactor under 1 atm of Ar. Samples were preheated from the bottom, after which SHS reaction was initiated from the butt. Temperature was monitored with three W/Re thermocouples. Depending on heating rate, temperature gradient along the sample depth had a value of 50–150 deg/mm. The samples obtained exhibited strong joining between Ta foil and Ti + 0,65C and also between the two pellets. The upper foil did not stick to the 5Ti + 3Si pellet, which can be explained by low temperature at the interface (1600 °C). At the Ta–TiC interface, the formation of Ti–Ta and (Ti, Ta)C interlayers was observed. The studies conducted demonstrate the possibility of Ta foil joining with ceramic materials under SHS conditions. Main conditions for this joint are the presence of a liquid phase and Ti + 0,65C combustion temperature matching the Ta substrate melting temperature. The results may be useful for deposition of multilayer functional coatings and functionally graded materials.

Dispersion-strengthened TiAl3-based material with uniform structure and high compression strength (σc ≈ 850 MPa) was SHS-produced from Ti–Al–B4C blends in a mode of thermal explosion by using the B4C particles coated with a TiB2/TiC layer as a strengthening agent and preliminary mechanical activation of Ti–Al powder mixtures. The Ti + 3Al mixtures were mechanically activated in a planetary mill for 3 or 6 min and then 10 or 20 wt % of coated B4C particles were added. Pelleted samples were placed into a reaction chamber and heated in an electric furnace under Ar to a self-ignition temperature. The process was optimized and recommended for practical implementation.

The experiments on the fabrication of materials based on the Ti–3Al–0.5Ta and 3Ti–2Al–Ta systems by self-propagating high-temperature synthesis (SHS) are performed. The influence of the composition of the initial mixture, dispersity of powders, and preliminary mechanical activation on the phase composition and structure of the SHS product is investigated. The optimal ratio between the mechanically activated and initial powder in a mixture for the synthesis of materials is determined. The dependence of the structure of final products on the structure of initial powders is established. The use of porous tantalum leads to the formation of the intermetallic matrix based on titanium aluminide with the uniform distribution of Ta particles. It is noteworthy that tantalum powders of both studied series (which differ by dispersity and morphology) partially reacted already at the stage of mechanical activation with the formation of the Al 2 Ta phase. It is shown that aluminum plays the leading role in processes of mechanical activation in Ti–Al–Ta reaction mixtures. Indeed, a considerable rise of unreacted tantalum particles in the microstructure of sintered samples is observed with a decrease in the amount of aluminum in the reaction mixture.

Explored was the deposition of multilayer TiC x –Ti x Si y -based coatings onto Ti substrate by SHS method. Sandwich-type green multilayer structures were assembled from Ti foils and Ti + 0.5C, Ti + Si, 5Ti + 3Si, and Ti + 0.65C pellets and ignited under 1 atm of Ar and a load (400 g). Burned sandwiches were characterized by SEM, EDS, and XRD. In all cases, we observed good metal–ceramic joining. Prerequisites for such a joining are (i) the presence of the liquid phase in combustion products, (ii) good metal–ceramic wettability, and (iii) closeness of reaction temperature to the melting point of substrate.

В данной работе проведены экспериментальные исследования по получению методом самораспространяющегося высокотемпературного синтеза (СВС) пористого материала на основе сплава титан – кобальт с последующей наплавкой (сваркой) полученного материала с титановой подложкой ВТ1-0. Методами растровой электронной микроскопии и рентгено-фазового анализа исследована структура и фазовый состав полученных образцов. Показано, что синтезированный сплав на основе Ti-Co имеет общую пористость 55–70 % c размером пор 200–800 мкм. Пористый материал на основе Ti-Co при характерном размере пор 100–200 мкм демонстрирует высокую открытую пористость (60 %), равномерно распределенную по образцу. Структурные характеристики синтезированных материалов могут регулироваться за счет изменения параметров синтеза и исходных размеров образцов. Также показано, что при сварке материала на основе Ti-Co с титановой подложкой ВТ1-0 зона контакта не имеет пор и других дефектов.

For over past years, interest of leading space agencies (NASA, JAXA, ESA, RSA, etc.) in SHS experiments under microgravity conditions has been increasingly growing. The first SHS experiments during a parabolic flight in Russia and aboard the MIR Space station gave promising results. Similar studies are now being carried out in various countries. The obtained data and assimilated experience have shown that SHS reactions can be used for (a) synthesis of high-porosity materials and regulation of structure formation in combustion products, (b) preparation of skeleton structures by combustion of particles suspended in vacuum, (c) generation of thermal energy, (d) generation of incandescent radiation, and (e) for in-space fabrication and in-situ repair works (welding, joining, cutting, coating, near-net-shape production, etc.). However, the results of the above studies (strongly scattered in the literature) still seem insufficient for elucidating the mechanism of combustion in. Indeed, the experiments were carried out by different researchers for a dozen of systems and for strongly different duration of microgravity (drop towers, parabolic flight of a plane, parabolic flight of a spacecraft, in space stations). No correlation has been made with the available data of SHS studies (oriented largely on practical implementation) in conditions of artificial gravity. In experiments, the combustion wave has enough time to spread over the sample while the structure formation, may not have. This implies that the process of wave propagation should always be identical, irrespective of the type of experimental technique and place of experiment. SHS experiments in space are attractive because (a) of low energy requirements, (b) processing cycle is short, (c) of process simplicity, (d) of versatility (wide range of suitable materials, and (e) the use of in-situ resources possible. To date, SHS experiments has already been performed aboard the International Space Station (ISS). Space technology has been developed for frontier exploration not only around the Earth orbit environment but also to the Moon, Mars, etc.