Structural, mechanical and corrosion evaluations of Cu/Zn/Al multilayered composites subjected to CARB process

Abstract In this research, the structure, tensile, wear, fracture toughness, and corrosion characteristics of Cu/Zn/Al multilayered composites fabricated by cross accumulative roll bonding (CARB) were determined. X-ray diffraction and scanning electron microscopy were used for structural analyses. Results showed that the crystallite size of the Cu matrix is reduced to about 50 nm at the ninth cycle of CARB, while the plastic instability and shear bands appeared in the layers after the third cycle. The tensile strength of the composites increased up to the third CARB cycle and then decreased to the ninth CARB cycle gradually. Typically, the maximum strength of about 330 MPa and elongation of almost 31.5% were obtained at the third and first cycles, respectively. A similar trend was found for the fracture toughness of the samples, so that the maximum fracture toughness of about 31 MPa.m1/2 was obtained at the third cycle. It was also shown that the wear mechanism of the composite samples changes by increasing the cycles, a compromise of abrasion and delamination wear. The accommodation of Al and Zn layers toward the surface of the composites by increasing the CARB cycles was also recognized to be responsible for the decrease of the corrosion resistance determined by polarization experiments.