Abstract
Ultrafine - grained materials represent a new generation of advanced materials exhibiting unique and technologically attractive properties. Today there are more than 30 different processes for manufacture of nanostructured materials, some of them include methods, which are based on severe plastic deformation (SPD). The ECAP, which is one of them, is nowadays one of most used and promising technologies for processing ultrafine - grained metals. The paper deals with influence of channels angle ECAP die on the state of stress, the state of strain and evolution of temperature, realized by mathematical simulation. Simulations were realized for IF steel in software product DEFORM based on FEM. It results from mathematical simulation, that the highest values of deformation forces and temperature have been achieved when the angle of channels was 90°. When the value of the angle of channel is increased, the value of effective strain and temperature is decreased. Based on the mathematical simulation, the concentration of the stress to transitional area of punch has been defined. This fact was later supported by the experiment, when during ECAP processing a superficial damage at the tension strain σ_{3, skut} = 2750 MPa has occurred.

Key words
SPD, ECAP, FEM, ultrafine, nanostructured materials, stress, strain

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