Effect of the Strain and Strain Rate on Microstructure Evolution and Superplastic Deformation Mechanisms


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Abstract

Parameters of superplasticity of the Al–7.6% Mg–0.6% Mn–0.25% Cr alloy have been studied in the range of 490–520°C, and the optimum temperature of deformation has been determined. The evolution of the grain structure in the bulk and on the surface of samples during the superplastic deformation at a temperature of 510°C has been analyzed. The contribution of grain-boundary sliding has been estimated in the strain-rate regime of superplastic deformation according to the results of the analysis of changes in the structure of the surface with preliminarily applied marker scratches. The contribution of grain-boundary sliding to the total deformation is 20–30%; the contribution of diffusion creep decreases from 40 to 20% with an increase in the deformation rate by an order of magnitude, from 1 × 10–3 to 1 × 10–2 s–1. The intragranular deformation is localized in the peripheral regions of grains and in the region of striated zones.

About the authors

O. A. Yakovtseva

Department of the Metallurgical Science of Nonferrous Metals, National University of Science and Technology MISiS

Author for correspondence.
Email: yakovtsevao@mail.ru
Russian Federation, Moscow, 119049

A. V. Mikhaylovskaya

Department of the Metallurgical Science of Nonferrous Metals, National University of Science and Technology MISiS

Email: yakovtsevao@mail.ru
Russian Federation, Moscow, 119049

A. D. Kotov

Department of the Metallurgical Science of Nonferrous Metals, National University of Science and Technology MISiS

Email: yakovtsevao@mail.ru
Russian Federation, Moscow, 119049

O. I. Mamzurina

Department of the Metallurgical Science of Nonferrous Metals, National University of Science and Technology MISiS

Email: yakovtsevao@mail.ru
Russian Federation, Moscow, 119049

V. K. Portnoy

Department of the Metallurgical Science of Nonferrous Metals, National University of Science and Technology MISiS

Email: yakovtsevao@mail.ru
Russian Federation, Moscow, 119049

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