Title: Elastic and plastic properties of ultrafine-grained magnesium

Authors: Zuzanka Trojanova, Pavel Lukac

Addresses: Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, Prague, Ke Karlovu 5, Praha 2, CZ-12116, Czech Republic. ' Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, Prague, Ke Karlovu 5, Praha 2, CZ-12116, Czech Republic

Abstract: Ultrafine-grained magnesium (UFG-Mg) samples were prepared by milling of powder in an inert atmosphere and subsequent compacted and hot extruded. The linear grain size estimated by X-ray line profile analysis was between 100 and 150 nm. Two developed peaks in the internal friction spectrum were obtained at temperatures about 375 K and about 631 K (1 Hz). The low temperature peak has dislocation origin, while the high temperature peak is conditioned by the grain boundary sliding. Compression tests were performed between room temperature and 300°C. The yield stress as well as the maximum stress decreases with increasing temperature. The dislocation substructure of deformed samples was investigated by the high resolution X-ray diffraction peak profile analysis. The influence of cyclic bending on the damping behaviour of UFG-Mg was determined at room temperature. Nucleation and growth of cracks were manifested by a rapid increase of damping with increasing number of cycles.

Keywords: ultrafine-grained magnesium; UFG-Mg; elastic properties; plastic properties; X-ray analysis; compression tests; stress; cyclic bending; damping behaviour; crack growth; crack nucleation.

DOI: 10.1504/IJMPT.2011.037209

International Journal of Materials and Product Technology, 2011 Vol.40 No.1/2, pp.120 - 139

Published online: 28 Feb 2015 *

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