Effect of La content on mechanical properties and electromagnetic interference shielding effectiveness of Mg-Zn-Y-La-Zr alloy

In recent years, a great demand exists for Mg alloy materials that combine excellent mechanical properties and electromagnetic interference shielding effectiveness (EMI SE). In this study, the effects of La content on the microstructure, mechanical properties, and EMI SE of Mg-6Zn-1Y-xLa-0.5Zr alloys are reported in detail. The microstructures of Mg-6Zn-1Y-xLa-0.5Zr alloys treated by extrusion all exhibit bimodal microstructure characteristics. Mg-6Zn-1Y-1.0La-0.5Zr alloys show a superior balance between mechanical properties and EMI SE. The UTS, YS, and elongation were 332.3 MPa, 267.3 MPa, and 16.2 %, respectively. Meanwhile, the EMI SE in the frequency range of 30–1500 MHz is 79–110 dB, and the excellent mechanical properties are due to the combined effect of fine-grain strengthening, second-phase strengthening, and heterogeneous structure strengthening. The excellent EMI SE is mainly attributed to the dense and diffusely distributed second phase providing more interfaces that can reflect electromagnetic waves. •The Mg-6Zn-1Y-xLa-0.5Zr alloys in the extruded state exhibited similar bimodal microstructural features.•The Mg‐6Zn‐1Y‐1La‐0.5Zr alloy in the extruded state achieved the highest strength without a significant decrease in elongation.•The enhancement of the EMI SE is attributed to the increase in La content, which resulted in the creation of more second phases within the alloy.