Roles of temperature and hydrostatic stress forces in severe plastic deformation of metal objects are considered. Methods and devices are described that allow the structural states of metal with high mechanical characteristics to be obtained upon plastic deformation at low temperatures under conditions of hydrostatic stress.Nowadays an increased degree of dispersion of a monolithic metal structure as a prerequisite for its improved physical-mechanical characteristics is obtained upon severe plastic deformation [1,2]. The common feature of the wellknown methods is that all of them are realized at high deformation degrees taken to mean an increased degree of mutual shear of the neighboring material layers irrespective of the calculation method; moreover, these methods are realized at increased or room temperatures. This is primarily determined by the processes of dynamic recovery proceeding in the deformable material. The higher the deformation temperature, the stronger the suppression of material dispersion upon plastic deformation.If we treat severe plastic deformation as a simple method of obtaining highly dispersed metal structure disregarding the deformation degree of the material, we should address ourselves to works on rolling and drawing of metals and alloys at cryogenic temperatures [3,4]. Two important conclusions were drawn in these works: first, by virtue of suppression of dynamic metal structure recovery, such a highly dispersed metal structure was formed which could not be formed upon deformation at room or increased temperatures. Second, though metal hardening was higher than that achieved upon deformation at room or increased temperature, by virtue of the geometry of forces applied in the deformation region, it was accompanied by an almost complete loss of plasticity thereby limiting the applicability field of these methods.These methods were further developed at Khar'kov Physical-Technical Institute 20 years ago. A method of metal deformation similar to hydroextrusion but at cryogenic temperatures (low-temperature quasihydroextrusion) was suggested in [5]. It was realized by using a solid body plastic at the deformation temperature for a pressure-transmitting medium. Objects were deformed in specially designed devices -attachments to conventional presses [6,7].To produce the material with preset properties, the influence of the deformation temperature on the character of the structure being formed should be understood. If an object is deformed at increased temperatures and after deformation termination the deformable object is cooled down to normal (room) temperature, it is possible to state that the thermally activated relaxation processes observed in this or that form under deformation practically vanish when returning to normal conditions. As a result, the material has the structure formed in it by the moment of termination of deformation influence and the start of temperature decrease. The situation is radically different when the material is deformed under conditions of deep cooling. It is wel...
