Beygelzimer Ya.Y.1, Orlov D.V.2
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1 Donetsk Phys.&Tech. Inst. of the NAS of Ukraine, Donetsk, UKRAINE; 2 DonSTU, Donetsk, UKRAINE
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Severe plastic deformations at last time attract intent attention of researchers that work in field of physical materials science. It's a powerful tool for transformation of materials structures. Basic structure forming regularities during the plastic deformation are determined by the parameters of initial structural material state, temperature-velocity deformation conditions, and mechanics of deformation process. The last is specified by scheme of external kinematics and force action on deformed volume (by the deformation scheme, tools geometry, conditions of contact friction etc.) and determine the series of basic process parameters: value of accumulated deformations intensity and deformations velocities in any spots, orientation of macroshear spatial evolution, configuration of deformed volume changes, homogeneity of stress and strain distribution etc. Each of these parameters influence in the corresponding way on formation of structure and properties of work materials.
There are two ways are used now for deriving severe plastic deformations without forming. The first way is torsion of disc-shaped blanks in Bridgmen anvils and the second one is equal channels corner extrusion of cylindrical and prismatic blanks.
A new method for deriving severe plastic deformations by hydromechanical extrusion of prismatic specimens throw a twist channel die is offered in this paper. All the cross-sections of the channel that is orthogonal to the extrusion axis are invariable along this axis. An inclination of twist line changes along the matrix height and on initials and final section it's equal to zero. The peculiarities of channel geometry bring that the form of specimen doesn't change. It allows multiple extrusion of one for the purpose severe deformations accumulation.
A change of dislocation arrangement and physicomechanical properties attached to twist extrusion is explored. The energy-power parameters and a value of accumulated deformation after one skip are calculated. The upper estimate for the toughness resource spending quantity is carried out. That allows estimate a maximum value of the skips without specimen failure. The suggestion on industrial use of the scheme for deriving unique physics and mechanical characteristics of bars from metals and alloys is advanced.
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