Scientific urgency of the project
In the most widespread traditional methods of processing of organic and inorganic materials in products, various catalysts and solvents and long technological operations of heating are used for transferring of material into plastic or hyperelastic conditions and with its subsequent cooling. Thus the basic difficulties connected to non-uniform existential distribution of temperature emerge, and the duration of these operations limits the general productivity of the processing equipment. Therefore the creation of new alternative technologies on manufacture of polymeric and ceramic products with traditional applications is important as well as the creation of new technologies of products which cannot be made in the traditional ways of material processing.
In this connection the developments of non-polluting and resource-saving technological processes of solid-phase technologies which are deprived the set forth above lacks are rather important. In essence, the topic under discussion is the development of new solid-phase chemical technologies aimed at the reception of various metal and nonmetallic alloys, at the reception of copolymers of incompatible monomers, of polymeric and ceramic products. The practical supplements of these technological processes are connected also with the reception of functionally gradient materials, alloys, ceramic and composite materials, especially clean chemical compounds, nanomaterials, etc. These technologies are very perspective and they are named as the technologies of XXI century. The big contribution to the creation and development of these technologies was made by the scientists working at the Institute of Structural Macrokinetics and Problems of Materiology (ISMPM) of the Science Centre of the Russian Academy of Science (RAS) in Tchernogolovka and by the scientists working at Tambov State Technical University (TSTU). For example, the first-ever automated (with the robot in shop of synthesis) manufacture of ceramic powders has been started which is based on the technology of the high-temperature self-spreading synthesis (HTSS) developed in ISMPM. In TSTU together with the joint-stock company "Tambov Chemical Scientific-Research Institute" and the joint-stock company – the factory “Progress” in Michurinsk the technology of firm pyrochemical sources of oxygen with the adjustable speed of target gas allocation with reference to the creation of independent devices for lungs artificial ventilation has been developed.
Examples of solid-phase technologies are method HTSS-extrusion (ISMPM) combining the processes of burning and high-temperature deformation of burning products and solid-phase extrusion of polymeric and composite materials (TSTU). The general feature of these methods is the use of processes of plastic deformation of firm materials. Now it is still difficult to predict the scales of practical application and prospects of solid-phase methods for products reception of organic and inorganic materials. Taking into account the advantage of these methods and results of the researches carried out before, it is possible to say, that these methods have all the preconditions for an effective utilization in the industry. This conclusion is also confirmed with the practical application experience of some products received by the methods of solid-phase technology: HTSS-ELECTRODES for welding deposition and electrospark alloying out of wolframfree firm alloys, high-temperature heating elements, products from firm alloys with the use of grinding waste products, stamped products of radio engineering purpose out of polytetrafluoroethylene having the elements of a snowmobile drive and other products.
The information received at research of solid-phase technology laws of organic and inorganic materials has fundamental character. It promotes the development of physics representations about plastic deformation mechanisms of firm materials that is now the subject of our detailed studying and abroad by virtue of its theoretical and applied value. However, despite of the great volume of the researches executed in the given direction, the full clearness in the treatment of these processes has not been achieved still. The practical value of the received knowledge about solid-phase deformation and the directed regulation of material properties by the creation of new special composite alloys is caused by the development of technological processes of new product reception and by the equipment introduced into industrial production.
The scientific purpose of the project:
Performance of the project will allow:
- Development of physics and science of materials and rheological management principles of microstructure formation of ceramic and composite polymeric materials at their deformation in conditions of solid-phase extrusion.
- Research of an opportunity of nanocrystal material reception by the method of solid-phase extrusion.
Influence on development of adjacent areas of a science
- to create the new scientific theory of structurization and high-temperature deformations of the organic and inorganic materials, including rheodynamics, non-stationary transportation and phase transformations;
- to create scientific bases of solid-phase extrusion methods for reception of products out of refractory connections, ceramic composite materials, firm alloys, polymers and other materials.
Studying of various fundamental aspects of structurization and deformation of the ceramic and composite materials received by the methods of solid-phase extrusion demands interdisciplinary synthesis of knowledge in various areas of science: rheology, structural mechanics, modern materiology, chemical kinetics, etc. Basic distinctions in mechanisms and dynamics of structurization at solid-phase extrusion puts new tasks in the field of physics materiology. In this connection it is required to study formation laws of deformation structure and anisotropic structures in various conditions of deformation in a combination to high static or dynamic pressure.
The fundamental importance of the project
The scientific interest to the problem of self-spreading high-temperature synthesis (HTSS) in conditions of power influences is caused by the aspiration to consider fundamental aspects of the interconnected course of burning processes and high-temperature deformation. In these conditions the thermal theory of burning is already unacceptable and there is an imperative need for the creation of a new phenomenological theory. It takes into account the influence of high thermal tension and structural defects on burning processes.
In the project the post-processes mechanisms and laws will be investigated at HTSS-extrusion: processes of crystallization, phase and structural transformations, diffusion transportation in biphase solid-liquid areas. On this basis the new scientific theory of structurization and high-temperature deformation of the hot HTSS-products, including rheodynamics, non-stationary transpotation and phase transformations will be created.
As it is known, powders of refractory connections are fragile and hardly-deformed. The absence of plasticity both at room, and at the raised temperatures sharply limits also the technological receptions of manufacturing from them products. The increase of plasticity of these materials is possible probably due to their transition into the superplastic condition. A necessary condition of the transition in the superplastic condition is the presence of a stable microstructure with the submicronic sizes of grains. Traditional ceramic materials usually have the sizes of grains equal to 1-10 microns. The important fundamental problem is the development of physics and chemical principles of structurization management in ceramics during its synthesis with the purpose of submicronic structure reception.
The practical importance of the project
The methods of solid-phase extrusion enable the direct reception of products from fragile hardly-deformed materials. In these processes their insufficiently studied property - ability to plastic deformation is shown. The advantages of HTSS process in conditions of plastic and superplastic deformation of product formation are obvious in comparison with other technologies. The process occurs for tens seconds (instead of hours). Thus the technology essentially becomes simpler and the necessity for the complex and expensive equipment disappears. The suggested process relates to non-polluting energy-and resource-saving methods of manufacture as it is not accompanied by pollution of environment, there are no waste products of manufacture, external heating is not used. All this makes the use of the suggested process a tempting one for reception of products of many refractory connections, such as ceramic and composite materials, firm alloys, polymeric composites, etc. It is possible to hope, that this technological process will find the big application in the future.
In the project the technological bases of new methods of solid-phase extrusion for reception of composite organic and inorganic materials and finished articles will be developed. An important point in development and improvement of these methods is the understanding of conditions of material compactibility and formation at various mechanical influences. Thus it is supposed to reveal the conditions of occurrence of the raised material plasticity and superplasticity at presence of the certain temperature-speed conditions.
Statement of scientific problems
We assume to carry out the theoretical and experimental research of the deformation phenomena and effects, macrokinetics and structurizations in systems based on TiB, TiC, TiSi, MoSi2 by various methods of HTSS-extrusion. The characteristic temperature range of material formation at these passing processes is rather wide: from temperature of burning up to temperature of recrystallization, therefore they are referred to hot methods of processing. However the conditions of carrying out the technological processes are unusual: short time (1-10 сек.), high temperatures and extremely big speeds of heating of initial components (up to 2:104 deg./sec.). All this causes basic distinctions in mechanisms and dynamics of structurization and puts new tasks in the field of physics materiology.
It is supposed to carry out mathematical modeling of high-temperature deformation processes and burning composite powder materials in view of their real rheological behaviour. On the basis of mathematical modeling the reasons and conditions of approach of the known experimental phenomena and the effects observable in the technology of HTSS-compacting will be explained: defect formation on the surfaces of samples, "swelling" of the squeezed out part of material and corking of a forming matrix at HTSS-extrusion, undercompacting and overpress at HTSS-pressing, crushing of grain at mechanical influences on a material and others. The new thermal and rheodynamic models of high-temperature deformation of burning products will be developed, in view of their real rheological behaviour in conditions of a combination of HTSS processes and plastic current. As a result of the performance of this part of the project it is supposed to study the influence of thermal, rheodynamic and structural factors on an opportunity of plastic and superplastic deformation of ceramic and composite materials (not only nanocrystalized), received by the methods of solid-phase extrusion.
The certain attention will be given to the creation of methods and devices for measurement of rheological properties of burning products in the field of high temperatures. The basic idea of methods of rheological measurements consists in the registration of dynamic and kinematic characteristics of burning product condensation in various modes of deformation. The novelty of methods is that it allows studying various rheological properties, such as viscosity, plasticity, elasticity depending on duration and depths of processes of structural transformations, and also from temperature and intensity of deformation.