Impact of the microstructure changes under cyclic groove pressing on the mechanical behavior of Mg-Mn-Ce magnesium alloy

E. N. Moskvichev ; V. A. Skripnyak ; V. V. Karakulov ; D. V. Lychagin

Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mehanika, no. 58 (2019), pp. 109-118

Résumé

In this study, the mechanical behavior of Mg-Mn-Сe magnesium alloy was investigated experimentally. The material tested had two structural states: coarse-crystalline (commercial rolled sheet) and microstructured state. The method of cyclic groove pressing (CGP), which allows processing of flat samples, is used to grind the material grain structure. The paper presents a description of the CGP and the results of investigation of the material microstructure at asreceived state and after three processing cycles. The tensile tests were carried out under quasistatic conditions. Analysis of the grained structure performed using the electron and optical microscopy methods showed that the material treatment up to the deformation degree of 3.5 by CGP method made it possible to obtain the blanks with a fined structure whose grain size distribution was in the range of 0.5–5 $\mu$m with average grain size of 2.2 $\mu$m. The uniaxial tensile tests were carried out at a strain rate of 10s$^{-1}$ at room temperature in order to assess the influence of structural modifications on the mechanical behavior. It was shown that the mechanical characteristics of material improved, and the yield stress and tensile strength increased by 30% and 17%, respectively. The grain structure changes were found to contribute to the activation of additional slip systems in the HCP lattice which enhanced the ultimate deformation to failure.

Détail

Keywords: magnesium alloys, severe plastic deformation, cyclic groove pressing, mechanical properties.
Mots-clés : microstructure