| Influence of Cold Severe Plastic Deformation on Structure and Texture of Pure Magnesium Daria Komkova1; Olga Antonova1; Vlada Petrova1; Alexey Volkov1; 1M.N. MIKHEEV INSTITUTE OF METAL PHYSICS OF THE URAL BRANCH OF THE RUSSIAN ACADEMY OF SCIENCES, Yekaterinburg, Russian Federation; PAPER: 309/Magnesium/Regular (Oral) SCHEDULED: 12:35/Thu. 24 Oct. 2019/Adonis ABSTRACT: Magnesium and its alloys are one of the lightest metals. The plasticity and formability of magnesium at room and lower temperatures, however, are poor because of its closely packed hexagonal crystal structure. Therefore, the deformation of magnesium by SPD methods is carried out at temperatures above 150 °C [1-3]. On the other hand, cold severe plastic deformation (SPD) of magnesium could lead to significant grain refinement and improvement of mechanical properties. At room and lower temperatures, however, the deformation of magnesium takes place mainly due to basal slip that causes formation of a sharp basal texture (0001) and prevents successful processing of magnesium at a high deformation strain. In this work, an attempt was made to deform magnesium at room and lower (cryogenic) temperatures. Our SPD method included lateral extrusion (LE) and cold rolling (CR). At first, cylindrical Mg-workpieces without basal texture (0001) were subjected by LE at room temperature (deformation strain is ε~3.9). As a result, 1-mm plates were obtained. It was found that the initial grain size was significantly reduced from 7 mm to 1-3 μm and weak basal texture was formed after LE [4]. Plates demonstrated high plasticity and were rolled to foils of 150-µm (ε~6) and 50 µm (ε~7) at room and cryogenic temperatures. CR did lead to nanostructure formation and the average grain size of thin foils deformed at low temperatures was about 5 – 7 µm. The main feature of the foils after CR was that their microstructure had a large number of new recrystallized grains and had areas of fine-grained and cellular substructures. New grains had non-equilibrium grain boundaries. After cryogenic deformation, a higher dislocation density in grains was seen in foils in comparison with room-temperature rolled foils. As for texture, basal texture (0001) became stronger after CR. The results of the work are of particular interest and they can be useful for practical application to create magnesium membranes for biotechnology and improve the mechanical properties of magnesium alloys. This work was carried out with support of the Russian Foundation for Basic Research (the RFBR project no. 18-33-00474) and within the framework of the State task (theme: Pressure No. АААА-А18-118020190104-3). References: 1. S. Biswas, S.S. Dhinwal, S. Suwas, Acta Materialia. 58 (2010) 3247-3261. 2. J. Swiostek, J. Goken, D. Letzig, K.U. Kainer, Materials Science and Engineering: A. 424 (2006) 223–229. 3. N.B. Tork, N. Pardis, R. Ebrahimi, Materials Science and Engineering: A. 560 (2013) 34–39. 4. O.V. Antonova, A.Yu. Volkov, D.A. Komkova, B.D. Antonov, Materials Science and Engineering: A. 706 (2017) 319-329. |
