Analysis of Deformation Behavior of Cu Processed by High Pressure Torsion

Vil D. Sitdikov ,  Rosa G. Chembarisova ,  Igor V. Alexandrov 

Institute of Physics of Advaced Materials, Ufa State Aviation Technical University (IPAM USATU), 12 K. Marx st., Ufa 450000, Russian Federation

Abstract

Mechanisms of severe plastic deformation (SPD), realized with the help of high pressure torsion (HPT), have still remained a point for discussion. In the current investigation the 3D version of Estrin-Tóth dislocation model [1] has been applied for analysis of deformation behavior of HPT Cu. Typical experimental curves for modeling have been taken from [2].
It has been shown that the growth of the source activity and dislocation sinks in grain-cell walls is a possible explanation of peculiarities of Cu deformation behavior during SPD with the accumulated resolved shear strain up to 14. This growth leads to an increase in dislocation density and to a possibility of annihilation processes as well as change of the interaction character between dislocations. In particular, a fraction of active dislocation sources is increases by 4.3 times when increasing the imposed pressure from 0.8 GPa to 8 GPa. This is explained by constrains applied to work of dislocation Frank-Reed sources by a low cell size. The fraction of dislocations, which has left the cell body, increases by 2.3 times. This is connected with the limited length of free dislocation path. A growth of probability of annihilation processes by 1.6 times testifies to extremely non-equilibrium state of the material as a result of SPD. At the same time, the coefficient, which characterizes the interaction of dislocations alongside with growing of the imposed pressure, is increased by 2 times.

1. L.S. Tóth, A. Molinari, Estrin Y., J. Eng. Mater. Technol. 2002, 124:71.
2. M. Zehetbauer, H.P. Stüwe, A. Vorhauer, E. Schafler and J. Kohout. Advanced Engeneering Materials, 2003, 5:5.

 

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Presentation: poster at E-MRS Fall Meeting 2005, Symposium I, by Vil D. Sitdikov
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-04-20 07:25
Revised:   2009-06-07 00:44