Preparation of Mg–6Zn–1La-0.5Zr alloy sheet with excellent mechanical properties and electromagnetic interference shielding effectiveness by extrusion plus rolling

In the field of specialty electronics and communications, there is a critical demand for magnesium (Mg) alloy sheets that possess exceptional mechanical properties and electromagnetic interference shielding effectiveness (EMI SE). This paper aims to develop a cost-effective and straightforward process for preparing a research proposal that combines excellent mechanical properties and EMI SE. After undergoing extrusion treatment, the Mg-6Zn-1La-0.5Zr alloy demonstrates an apparent bimodal microstructure, with an average grain size of approximately 2.55 μm. Subsequently, following a 37% rolling treatment, the grain size increases to about 5.29 μm. This increase in grain size is attributed to grain growth resulting from holding prior to the multi-pass rolling treatment. Notably, the Mg-6Zn-1La-0.5Zr alloy, subjected to extrusion and 75% rolling treatment, exhibits remarkable mechanical properties and EMI SE, with ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) values of 337.5 MPa, 227.3 MPa, and 12.5%, respectively. Furthermore, the EMI SE ranges from 79 dB to 110 dB within the frequency range of 30-1500 MHz. The exceptional mechanical properties are attributed to the synergistic effects of various strengthening mechanisms, including grain boundary strengthening, second phase strengthening, dislocation strengthening, heterogeneous deformation-induced strengthening, and texture. Similarly, the superior EMI SE is attributed to the alloy's higher electrical conductivity, strong basal texture, and uniformly diffused second phase.