The microstructure, electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of CNTs/Mg Matrix composites prepared by accumulative roll bonding (ARB) were systematically investigated to understand the effects of CNTs on the electromagnetic interference shielding effectiveness property of magnesium. A model based on the shielding of the electromagnetic plane wave was used to theoretically discuss the EMI shielding mechanisms of ARB-processed composites. The experimental results indicated that the methods were feasible to prepare laminated composites. The SE of the material increased gradually with the increase of electrophoretic deposition time. When the electrophoretic deposition time reached 8 min, the value of SE remained 87–95 dB in the frequency range of 8.2–12.4 GHz. The increase in SE was mainly attributed to the improvement in the reflection and multiple reflection losses of incident electromagnetic wave due to the increased amounts of CNTs and interfaces. The methods provided an efficient strategy to produce laminated metal matrix composites with high electromagnetic shielding properties.

In order to study the metadynamic recrystallization behavior of 34CrNi3MoV steel, a double-pass isothermal compression experiment and a single-pass thermal interval experiment were designed and conducted to obtain the stress–strain curves under different deformation conditions and to explore the action law of deformation parameters during the compression process. The softening rate was calculated by the compensation method, and the grain size in the recrystallization region was measured. Based on the obtained data, the effects of deformation temperature (T), interval time (t), and strain rate ($\dot{\epsilon }$) on the softening rate and grain size of 34CrNi3MoV steel during metadynamic recrystallization were analyzed. The results show that increasing the deformation temperature, extending the interval time, and increasing the strain rate are all beneficial to the improvement of the metadynamic recrystallization softening rate and that fine and uniform new grains can be obtained under a high strain rate. However, in high-temperature conditions, mixed crystallization can easily occur, which is not conducive to grain refinement. Based on the true stress–strain data and experimental data on the grain size, a relevant model for metadynamic recrystallization of 34CrNi3MoV steel was established using mathematical analysis of regression equations. The average relative error AARE between the constructed dynamic model and the grain size model and the experimental results are 6.48% and 1.30%, respectively. This indicates that the model has high predictability.

This study mainly attempts to develop Mg-based alloy materials with excellent corrosion resistance by means of multi-principal alloying. The alloy elements are determined based on the multi-principal alloy elements and the performance requirements of the components of biomaterials. Mg₃₀Zn₃₀Sn₃₀Sr₅Bi₅ alloy was successfully prepared by vacuum magnetic levitation melting. Through the electrochemical corrosion test with m-SBF solution (pH7.4) as the electrolyte, the corrosion rate of alloy Mg₃₀Zn₃₀Sn₃₀Sr₅Bi₅ alloy decreased to 20% of pure Mg. It could also be seen from the polarization curve that when the self-corrosion current density is low, the alloy shows superior corrosion resistance. Nevertheless, with the increase in self-corrosion current density, although the anodic corrosion performance of the alloy is obviously better than that of pure Mg, the cathode shows the opposite situation. The Nyquist diagram shows that the self-corrosion potential of the alloy is much higher than that of pure Mg. In general, under the condition of low self-corrosion current density, the alloy materials display excellent corrosion resistance. It is proved that the multi-principal alloying method is of positive significance for improving the corrosion resistance of Mg alloys.

Laminated composite with multi-layer interfaces has better electromagnetic interference shielding performance, which has attracted great attention. In this work, magnesium matrix laminated structure materials were prepared through Accumulative Roll Bonding (ARB). Microstructure, electrical conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) of ME21/Mg laminated materials were investigated to understand the effect of layered structure and the change of microstructure on the electromagnetic shielding property. The results showed: the precipitated secondary phase and introduced interfaces could provide multiple reflections, attenuate the electromagnetic waves and improve the SE value. The electrical conductivity of 2-cycle increased to 21.04*10⁶ S m⁻¹, which was 17.74% higher than that of ME21 alloy, the intensity of texture of ME21 layer increased with the rolling passes, which contributed to the improvement of the electrical conductivity as well as the attenuation of reflection. The layered composite exhibited better shielding effectiveness compared with the ME21, in the 8.2–12.4 GHz test frequency, the SE was 98–107 dB. The shielding mechanism of layered materials was explained, which provided guiding for the efficient shielding of electromagnetic waves.