Polymers

Micromechanism of plastic deformation enhancement in ultrafine-grained Al–Cu–Zr alloy after annealing and additional deformation

M. Yu. Gutkin^abc, T. S. Orlova^d, N. V. Skiba<sup>d

a</sup> Institute of Problems of Mechanical Engineering, Russian Academy of Sciences, St. Petersburg, Russia
^b St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia
^c Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
^d Ioffe Institute, St. Petersburg, Russia

Abstract: A theoretical model which describes a micromechanism of plasticity enhancement in an ultrafine-grained Al–Cu–Zr alloy after annealing and additional deformation is suggested. Within the framework of the model, it was shown that nanoprecipitates of the secondary phase Al$_2$Cu in the grain boundaries become the effective sources of the lattice dislocations in the presence of a large number of the grain boundary dislocations near the nanoprecipitates. The theoretical dependences of the flow stress on the degree of the plastic deformation demonstrate good qualitative and quantitative agreement with the experimental data. The emission of the lattice dislocations from nanoprecipitates provides higher plasticity compared to the emission of the lattice dislocations from the triple junctions of the grain boundaries.

Keywords: ultrafine-grained materials, aluminum alloys, nanoprecipitates, annealing, severe plastic deformation by high-pressure torsion, dislocations, grain boundaries.

Received: 24.03.2023
Revised: 24.03.2023
Accepted: 31.03.2023

DOI: 10.21883/FTT.2023.05.55508.42

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