Mechanical properties, strength physics and plasticity

Influence of strain rate on the effect of plasticization of high-strength ultrafine-grained Al–Cu–Zr alloy

D. I. Sadykov^a, T. S. Orlova^b, M. Yu. Murashkin<sup>c

a</sup> St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia
^b Ioffe Institute, St. Petersburg, Russia
^c Ufa University of Science and Technology, Ufa, Russia

Abstract: The influence of the strain rate on the plasticization effect (PE) of ultrafine-grained (UFG) Al–1.47Cu–0.34Zr (wt%) alloy structured by high pressure torsion. A significant increase in plasticity (more than 2 times) while maintaining a high level of strength (ultimate tensile strength $\sim$ 465 MPa) in the UFG alloy was achieved as a result of additional deformation-heat treatment (DHT), consisting of low-temperature annealing and a small additional deformation. It is shown that the PE after DHT is retained when the strain rate changes from 10$^{-4}$ to 10$^{-3}$ s$^{-1}$ and decreases by half with its further increase to 10$^{-2}$ s$^{-1}$. The values of the strain-rate sensitivity coefficient for the UFG Al–1.47Cu–0.34Zr (wt%) alloy were determined in both states before and after DHT. Possible reasons of the PE suppression at high strain rates ($\ge$ 10$^{-2}$ s$^{-1}$) are discussed.

Keywords: aluminum alloys, severe plastic deformation, ultrafine-grained structure, strength, plasticity, strain-rate sensitivity.

Received: 22.02.2022
Revised: 22.02.2022
Accepted: 24.02.2022

DOI: 10.21883/FTT.2022.06.52410.297

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