Investigation of microstructure, hardness, electromagnetic shielding effectiveness, and corrosion properties of Nickel/Zinc composites fabricated by severe plastic deformation

The content of composite constituents and their arrangement in multilayered composites affect the composites' properties. Therefore, in this study, the effect of layer arrangement and layer thickness of Ni-Zn composites on microstructure, grain structure, corrosion resistance, shielding feature, and hardness were investigated. To this end, the Ni/Zn/Ni and Zn/Ni/Zn composites with different thicknesses of layers were fabricated by accumulative roll bonding (ARB) process. With an increase in ARB cycles, the reinforcing layers were broken and dispersed in the matrix. Additionally, a finer distribution of reinforcing layers in the matrix was obtained in Ni/Zn/Ni composites compared to Zn/Ni/Zn composites. Furthermore, the Ni and Zn layers revealed ultra-fine grain structure after the seventh ARB cycle. By increasing the thickness of the harder layer, finer grains were obtained in composites. In addition, the shielding efficiency of composites was improved by increasing the number of cycles and thickness of reinforcing layers. Also, the hardness of Zn and Ni layers grew with an increase in cycles and thickness of the harder layer. With an increase in cycles, the Ni/Zn/Ni composites were less corroded while the corroded regions in the Zn/Ni/Zn composite increased. By increasing the thickness of the Ni layer, the composites were less corroded at all cycles.