This article is cited in 7 papers

Mechanical properties, strength physics and plasticity

Mechanism of hardening of ultrafine-grained aluminum after annealing

M. Yu. Gutkin^abc, T. A. Latynina^c, T. S. Orlova^cd, N. V. Skiba<sup>ab

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

Abstract: A theoretical model is proposed that describes the mechanism of hardening of ultrafine-grained aluminum, obtained by severe plastic torsion deformation, after low-temperature annealing. In the framework of the model, hardening is realized due to the sequential transformation of the grain-boundary dislocation structure. In particular, plastic deformation occurs through the emission of lattice dislocations from triple junctions of grain boundaries containing pile-ups of grain-boundary dislocations, the subsequent sliding of lattice dislocations in the bulk of the grain, and the formation of walls of grain-boundary dislocations climbing along opposite grain boundaries. The energy characteristics and critical stresses for the emission of lattice dislocations are calculated. The theoretical dependences of the flow stress on the plastic deformation are plotted, which show good qualitative and quantitative agreement with experimental data.

Keywords: ultrafine-grained aluminum, hardening by annealing, microplasticity mechanisms.

Received: 16.05.2019
Revised: 16.05.2019
Accepted: 21.05.2019

DOI: 10.21883/FTT.2019.10.48257.481

 English version: Physics of the Solid State, 2019, 61:10, 1790–1799

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