Simultaneous achievement of high electromagnetic shielding effectiveness (X-band) and strength in Mg-Li-Zn-Gd/MWCNTs composite

•Mg-9Li-3Zn-0.5Gd/MWCNTs composite was prepared by the method of heat treatment+EPD+ARB.•The high density dislocations introduced by ARB process promoted the dynamic precipitation of the nano-scale MgZn2 phases.•The added MWCNTs could induce the precipitation of fine and dense ultrafine nanoparticle W-phases.•Simultaneous achievement of high EMI SE (X-band) and strength in Mg-9Li-3Zn-0.5Gd/MWCNTs composite. A ultra-light Mg-9Li-3Zn-0.5Gd/MWCNTs composite was designed and fabricated through accumulative roll bonding (ARB) process, which realized high electrical conductivity and multiple reflections of EM waves inside the material and improved the EMI SE of the composite. [Display omitted] In this study, the Mg-9Li-3Zn-0.5Gd/MWCNTs composite was prepared by the method of heat treatment+electrophoretic deposition (EPD)+accumulative roll bonding (ARB), and the microstructure, electrical conductivity, electromagnetic (EM) shielding properties in the X-band (8.2–12.4 GHz) and strength were evaluated. The microstructure characterization shows that, after five ARB cycles, MWCNTs are uniformly distributed in the Mg-Li matrix, and severe plastic deformation promotes the dynamic precipitation of the nano-scale secondary phase particles, which greatly weakens the lattice distortion of the Mg-Li matrix. Besides, MWCNTs induces a large amount of ultrafine nano-scale W-phase precipitation. The property evaluation indicates that the electrical conductivity, ultimate tensile strength and yield strength of C-ARB5 sheet are 7.60 MS/m, 280 MPa and 264 MPa, respectively, which are increased by 1.9%, 4.2% and 4.9% compared with ARB5 sheet. In the X-band frequency range, the electromagnetic interference (EMI) shielding effectiveness (SE) of ARB5 sheet is 77–96 dB, and that of C-ARB5 sheet is increased to 89–100 dB. The improvement of C-ARB sheets property is mainly attributed to the uniformly distributed MWCNTs inducing precipitation of ultrafine nano-scale W-phase.